S-1/A

Large accelerated filer

Accelerated filer

Non-accelerated filer

Smaller reporting company

Emerging growth company

S-1/A 1 d574486ds1a.htm S-1/A S-1/A

As filed with the Securities and Exchange Commission on July 17, 2023.

Registration No. 333-272600

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

AMENDMENT NO. 2

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Turnstone Biologics Corp.

(Exact name of registrant as specified in its charter)

Delaware

2836

83-2909368

(State or other jurisdiction of

incorporation or organization)

(Primary Standard Industrial

Classification Code Number)

(I.R.S. Employer
Identification No.)

9310 Athena Circle, Suite 300

La Jolla, California 92037

(347) 897-5988

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Sammy Farah, M.B.A., Ph.D.

President and Chief Executive Officer

Turnstone Biologics Corp.

9310 Athena Circle, Suite 300

La Jolla, California 92037

(347) 897-5988

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Divakar Gupta

Ryan Sansom

Cooley LLP

55 Hudson Yards

New York, New York 10001

(212) 479-6000

P. Joseph Campisi, Jr.

Chief Legal Officer

Turnstone Biologics Corp.

9310 Athena Circle, Suite 300
La Jolla, California 92037

(347) 897-5988

Nathan Ajiashvili

Salvatore Vanchieri

Latham & Watkins LLP

1271 Avenue of the Americas

New York, New York 10020

(212) 906-1200

Approximate date of commencement of proposed sale to the public: As soon as practicable after this Registration Statement is declared effective.

If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box. ☐

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

Subject to Completion

Preliminary Prospectus dated July 17, 2023

P R O S P E C T U S

5,800,000 Shares

LOGO

Common Stock

This is Turnstone Biologics Corp.’s initial public offering. We are selling 5,800,000 shares of our common stock.

We expect the initial public offering price to be between $12.00 and $14.00 per share. Currently, no public market exists for the shares of our common stock. We have applied to list our common stock on the Nasdaq Global Market, or Nasdaq, under the symbol “TSBX.” However, no assurance can be given that our listing application will be approved. If our listing application is not approved by Nasdaq, we will not be able to consummate this offering.

We are an “emerging growth company” and a “smaller reporting company” as defined under the federal securities laws and, as such, have elected to comply with certain reduced public company disclosure standards. See the section titled “Prospectus Summary—Implications of Being an Emerging Growth Company and a Smaller Reporting Company.”

Investing in our common stock involves risks that are described in the “Risk Factors” section beginning on page 16 of this prospectus.


	Per Share	Total
Public offering price	$	$
Underwriting discount⁽¹⁾	$	$
Proceeds before expenses, to us	$	$

(1)	We refer you to the section titled “Underwriting” beginning on page 232 of this prospectus for additional information regarding underwriting compensation.

The underwriters may also exercise their option to purchase up to an additional 870,000 shares of common stock from us, at the public offering price, less the underwriting discount, for 30 days after the date of this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The shares will be ready for delivery on or about , 2023.

Joint Book-Running Managers


BofA Securities		Leerink Partners		Piper Sandler

The date of this prospectus is , 2023.

TABLE OF CONTENTS


	Page
PROSPECTUS SUMMARY		1
RISK FACTORS		16
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS		91
MARKET, INDUSTRY AND OTHER DATA		92
USE OF PROCEEDS		93
DIVIDEND POLICY		95
CAPITALIZATION		96
DILUTION		98
MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS		101
BUSINESS		123
MANAGEMENT		183
EXECUTIVE COMPENSATION		194
CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS		209
PRINCIPAL STOCKHOLDERS		213
DESCRIPTION OF CAPITAL STOCK		217
SHARES ELIGIBLE FOR FUTURE SALE		224
MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS		227
UNDERWRITING		232
LEGAL MATTERS		241
EXPERTS		242
WHERE YOU CAN FIND MORE INFORMATION		243
INDEX TO CONSOLIDATED FINANCIAL STATEMENTS		F-1

We and the underwriters have not authorized anyone to provide you with any information or to make any representations other than those contained in this prospectus or in any free writing prospectuses we have prepared. We and the underwriters take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where offers and sales are permitted. The information contained in this prospectus or in any applicable free writing prospectus is accurate only as of the date of this prospectus or any such free writing prospectus, as applicable, regardless of its time of delivery or of any sale of our common stock. Our business, financial condition, results of operations and future growth prospects may have changed since that date.

For investors outside the United States: Neither we nor any of the underwriters have done anything that would permit this offering or possession or distribution of this prospectus in any jurisdiction where action for that purpose is required, other than in the United States. Persons outside of the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of the shares of our common stock and the distribution of this prospectus outside of the United States.

PROSPECTUS SUMMARY

This summary highlights information contained elsewhere in this prospectus. This summary does not contain all of the information you should consider before investing in our common stock. You should read this entire prospectus carefully, including the sections titled “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” “Special Note Regarding Forward-Looking Statements,” and our consolidated financial statements and the related notes included elsewhere in this prospectus, before making an investment decision. Unless the context otherwise requires, references to “we,” “us,” “our,” “the company” and “Turnstone USA” refer to Turnstone Biologics Corp., a Delaware corporation, and our wholly owned subsidiaries, Turnstone Biologics Inc., a corporation under the Canada Business Corporations Act, which we refer to in this prospectus as Turnstone Canada, and Myst Therapeutics, LLC, a Delaware limited liability company.

Overview

We are a clinical stage biotechnology company focused on developing new medicines to treat and cure patients with solid tumors. Approved immunotherapies represent a significant advancement in the treatment of solid tumors, but many patients either do not respond or experience relapsed disease following an initial response. We believe the most significant challenge to creating curative immunotherapies in these patients is the low numbers of T cells that can recognize and attack the tumor, which we refer to as tumor-reactive T cells. To address this problem, we are pioneering a differentiated approach to tumor infiltrating lymphocytes, or TILs. We are developing next generation TIL therapies by selecting the most potent (meaning able to mediate an anti-tumor response) and tumor-reactive T cells, which we refer to as Selected TILs. Unlike other approaches that rely on standard “bulk TILs” that have demonstrated objective responses in clinical trials only in limited tumor types, we are developing our Selected TILs for potential treatment across the majority of solid tumors. We have initiated two Phase 1 clinical trials for TIDAL-01, including a multi-site trial for the treatment of breast cancer, colorectal cancer, and uveal melanoma, and an investigator sponsored trial with H. Lee Moffitt Cancer Center and Research Institute, Inc., or Moffitt, in both cutaneous and non-cutaneous melanomas. We discuss the nature of this investigator-sponsored trial, including how this trial differs from a clinical trial sponsored by our company, as well as our roles and responsibilities in the trial, in more detail below. We intend to provide an initial clinical update across these two trials in mid-2024. We are also actively advancing our preclinical pipeline programs including TIDAL-02, our next Selected TIL program, and our TIDAL-01 viral immunotherapy combination program. We define objective response as a patient experiencing a partial response or complete response to any given therapy.

Solid tumors present a major burden to society, with high mortality and poor outcomes associated with more advanced disease. Several key factors, such as tumor heterogeneity (meaning differences in the characteristics, including variable tumor antigen expression, between cancer cells within a patient’s tumor, between tumors within the same patient and/or between different patients’ tumor(s)) and challenging tumor microenvironments, or TMEs, have made treatment of solid tumors more difficult than treatment of hematologic cancers. Immunotherapies that activate the immune system to enhance and/or create anti-tumor immune responses, such as immune checkpoint inhibitors, or ICIs, have improved outcomes for some patients. However, more than 85% of cancer patients fail to respond to ICI therapy. The effectiveness of ICIs is heavily dependent on the presence of tumor-reactive T cells that ICIs can reinvigorate, and many patients lack a sufficient number of T cells that recognize the target tumor. Therefore, we believe new treatments that can expand and enhance the patient’s tumor-reactive T cells are needed.

TILs are a type of cell therapy that harness the patient’s own immune cells to target their own tumors. TIL therapy involves the isolation of lymphocytes from the patient’s tumor, expansion of the isolated cells outside the body, and then infusion of the cells back into the patient. TILs have the ability to penetrate, recognize, and kill cancer cells and offer potential to treat or cure solid tumors. Because TILs include an expansive breadth of lymphocytes that are specific to the patient’s tumor antigens, we believe they have the potential to overcome tumor heterogeneity which often presents a significant challenge for other therapies. Clinical trials with standard “bulk

TILs,” the first generation of TIL therapy that involves isolation and expansion of all of the TILs in the tumor sample, have shown objective responses in clinical trials in limited solid tumor types.

To date, several hundred patients in the United States have received bulk TIL therapies, with the greatest success observed in metastatic melanoma. In metastatic melanoma patients refractory to ICI therapy, specifically PD-(L)1 treatments (meaning monoclonal antibodies targeting the immune checkpoint PD-1), bulk TIL monotherapy has yielded objective response rates (meaning the percentage of patients experiencing a partial response or complete response in any given study) of approximately 30% to 50%, with complete response rates (meaning the percentage of patients with complete eradication of measurable disease in the patient and no new lesions) ranging from approximately 5% up to 20%. If a complete response lasts the lifespan of a patient it would be considered as a cure – in general clinical practice patients are referred to as “cured” if they remain in complete response for greater than five years as the probability of their disease recurrence is low. Beyond metastatic melanoma, bulk TIL therapy has demonstrated therapeutic potential in a limited number of solid tumors, including squamous cell carcinoma of the head and neck, cervical cancer, and non-small cell lung cancer. We believe that the activity of TILs is driven by the subset of tumor-reactive T cells, and that the key limitation for bulk TILs is the small number and proportion of tumor-reactive T cells that make up the bulk TIL product (reported median less than 3%, Lowery et al., 2022). We believe increasing the proportion and diversity of tumor-reactive T cells in a TIL product can expand the utility of TILs to a greater breadth of tumor types, where bulk TILs have not shown objective responses in clinical trials to date.

Our Solution: Selected TILs

We are developing next generation TIL therapies for the potential treatment of multiple solid tumors. There are no TIL therapies that have received FDA approval to date. To our knowledge, at present there are no therapies in clinical development that provide curative outcomes for the majority of patients in our chosen solid tumor indications. Our innovative Selected TIL approach focuses on selecting and expanding the most potent tumor-reactive T cells to overcome the limitations of bulk TILs. This approach expands upon work conducted in academia that demonstrated improved clinical responses for certain selected TILs in solid-tumor types where bulk TILs have not shown objective responses in clinical trials. We are leveraging this work to establish a standardized manufacturing process for large scale production of our Selected TILs.

Our Selected TIL approach employs the following foundational principles with the goal of yielding the greatest number and proportion of tumor-reactive T cells in our TIL product candidates:

(1)

Unbiased identification of patient-specific tumor antigens: We seek to identify the most comprehensive set of patient-specific tumor antigens. We use an unbiased identification process that aims to find and capture the greatest diversity of antigens with the potential to drive the most robust T cell response. Our proprietary approach is unlike other TIL products that are biased toward a specific subset or class of antigen(s), which may miss relevant tumor antigens or focus on the wrong targets.

(2)

Selection of greatest breadth of tumor-reactive T cells from patient extracted TILs: Our goal is to capture and isolate the greatest number and proportion of a patient’s tumor-reactive T cells that have the potential to attack and destroy heterogeneous solid tumors. We aim to select the greatest diversity of T cells by using a function-based screening process that confirms reactivity to the identified patient-specific tumor antigens rather than relying on a bioinformatics-based prediction algorithm that may not be truly predictive.

(3)

Expansion of tumor-reactive T cells and removal of non-tumor-reactive bystander cells: We expand our selected tumor-reactive TIL population to magnitudes consistent with bulk TIL products and

actively remove unnecessary bystander cells. This selective expansion resulted in a substantially higher proportion of tumor-reactive T cells in the final product in comparison to the relatively infrequent tumor-reactive T cells that are routinely found in bulk TIL. Based on our non-clinical studies across multiple tumor samples to date, we have been able to achieve tumor-reactive T cell frequencies in our Selected TIL drug product of up to 62%, with a median frequency of 23%. With ongoing continuous process improvements as part of our manufacturing strategy we are targeting >70% tumor-reactive T cells in our drug product as we advance clinical development.

The potential advantages of Selected TILs over bulk TILs are depicted in the figure below.

LOGO

The Selected TILs approach described above is inherently designed to select for and characterize the active TIL product—the tumor-reactive T cells. Bulk TIL approaches do not select for the active TIL product and have consequently faced challenges in product characterization and potency assay development. We define potency as the specific ability or capacity of the product, as indicated by appropriate laboratory tests or by adequately controlled clinical data obtained through the administration of the product in the manner intended, to effect a given result. We believe that our Selected TIL approach has the potential to facilitate the development of potency release assays to support regulatory requirements and avoid the characterization challenges of bulk TILs.

Supporting Clinical Evidence

We believe the growing body of prospective and translational clinical data in the TIL field supports the potential of our Selected TIL approach. Third-party studies have demonstrated that the anti-tumor activity of bulk TILs is driven by a small subset of tumor-reactive T cells in the bulk TIL product. Furthermore, clinical studies in academic centers utilizing rudimentary selection strategies for tumor-reactive T cells have reported responses including tumor regressions in a single patient bile duct study (Tran et. al., 2014) and a single patient colorectal cancer study (Tran et. al., 2016), one complete response and two partial responses out of six patients in a breast cancer study (Zacharachis, et.al 2022), and two complete responses and one partial response out of seven patients who received a TIL product with confirmed tumor reactivity, in a non-small cell lung cancer study (Creelan et. al., 2021). We define partial response as a patient experiencing a reduction in tumor size or volume as defined by the applicable standard, e.g. response evaluation criteria in solid tumors or RECIST, and no new lesions. A partial response does not indicate that a patient is cured of their disease.

Building a Product Pipeline to Further Enhance the Quality and Function of Selected TILs

Our Selected TIL approach sets us apart from others in the industry that are utilizing bulk TILs, including newer bulk TIL approaches that introduce genetic modifications and culture media additives to enhance TIL quality and function (meaning the viability of the TILs and their ability to produce cytotoxic and immune activating cytokines). We believe that without the optimal starting population of tumor-reactive T cells, further enhancements or modifications to bulk TILs are unlikely to succeed in extending their potential utility beyond the limited tumor types where bulk TILs have already shown objective responses in clinical trials. We are also expanding our product pipeline by making additional modifications to our proprietary Selected TILs and deploying them in differentiated combination strategies to further enhance TIL quality and function.

Modifications to Enhance TIL Quality

We are developing pipeline programs where we are evaluating enhanced culture conditions during the TIL production process to maintain and further improve TIL quality ex vivo. These enhanced culture conditions are designed to incorporate a mix of cytokines with the potential to rejuvenate dysfunctional and/or exhausted T cells.

Additionally, we plan to introduce functional genetic modifications into our pipeline programs that may drive potential for more sustained TIL quality and persistence, or ability of the TILs to survive and proliferate, in vivo. These gene edits will be designed to modify the tumor-reactive T cells to proliferate while resisting exhaustion post infusion, minimize their dependence on exogenous IL-2 for in vivo proliferation, and maintain their potential to kill tumors in suppressive tumor microenvironments. We are currently evaluating and prioritizing clinically informed targets for these genetic modifications.

Virus Combinations

Viral immunotherapy is a therapeutic modality with widespread potential to drive and modulate immune responses to solid tumors. Many viruses have inherent oncolytic activity that can be modulated through genetic engineering. These viruses preferentially infect, replicate within, and kill malignant tumor cells, and can induce broad immune responses. Viral immunotherapies are designed to convert immunologically unresponsive “cold” tumor microenvironments to more reactive “hot” tumor microenvironments and thereby enhance the activity of other immunotherapies.

We are strongly positioned to combine our Selected TIL products with our proprietary viral immunotherapies utilizing two distinct approaches:

•

viral immunotherapy pre-treatment (prior to TIL extraction): optimize TIL harvest and broaden access to indications that are currently less amenable to generating effective TIL products; and

•

viral immunotherapy post-treatment (following delivery of the TIL product): optimize TIL trafficking and function and further increase the activity of our TIL therapies, if approved.

Our Pipeline

We are applying our Selected TIL approach for potential treatment of a wide range of solid tumors. We are developing a broad pipeline aimed at improving outcomes for patients, as illustrated in the chart below.

LOGO

*	Investigator sponsored trial at Moffitt Cancer Center

Investigator sponsored trials are clinical trials where the investigator of the trial is also the “sponsor” of the trial for regulatory purposes. An “investigator” conducts clinical investigations and is the person under whose immediate direction the study drug is administered or dispensed to patients. A “sponsor” initiates and takes responsibility for a clinical investigation. A person who both initiates and conducts a clinical trial, and is responsible for all regulatory requirements, is designated as a “sponsor-investigator” by the FDA. Clinical investigators at academic medical centers who initiate clinical trials with a lawfully marketed drug to be used in a patient population or indication not within the official labeling often fit within this designation. In addition, as is the case with our investigator-sponsored trials, a company may provide a sponsor-investigator with supply of its unapproved product candidate and funding for the trial. Investigators who initiate and conduct such trials are responsible for obtaining an IND from the FDA and for ensuring compliance with the IND and associated regulatory requirements. As provided by the FDA’s regulations, the sponsor of a clinical trial is responsible for, among other things, selecting qualified investigators, providing them with the information they need to conduct the trial properly, ensuring proper monitoring of the trial, ensuring that the trial is conducted in accordance with the protocols contained in the IND, maintaining an effective IND with respect to the trial, and ensuring that the FDA and all participating investigators are promptly informed of significant new adverse effects or risks with respect to the drug. In contrast, in a company-sponsored trial, the pharmaceutical company whose drug will be studied is the sponsor of the trial and, as such, is responsible for ensuring compliance with all regulatory requirements, including obtaining the IND.

sponsored trial, which is fully funded by us, Moffitt is solely responsible for regulatory interactions, trial conduct and manufacture of TIDAL-01 at the Moffitt Cancer Cell Therapy Facility, with input and support from us at Moffitt’s discretion. Investigators at Moffitt are also solely responsible for the design of the trial and patient selection and enrollment, where we remain in close contact with the investigators to provide our input if appropriate. Any data disclosures will be made in collaboration with us and any improvements to the TIDAL-01 manufacturing process are solely at our discretion. We intend to provide an initial clinical update across these two trials in mid-2024.

Our next Selected TIL program, TIDAL-02, is being designed to encompass a next generation streamlined manufacturing process for tumor-reactive T cells and additional modifications to enhance TIL quality and function. We believe that TIDAL-02 has the potential to address the medical need in solid tumor indications that are distinct from and complementary to TIDAL-01. TIDAL-02 is currently in preclinical development.

We intend to evaluate the combination of TIDAL-01 with viral immunotherapy through two approaches: (1) treatment of the patient with viral immunotherapy prior to TIL extraction to optimize TIL harvest and broaden applicability to additional tumor types with low immune cell infiltration and (2) treatment of the patient with viral immunotherapy following treatment with TIDAL-01 to optimize TIL trafficking and infiltration into solid tumors and to support the anti-tumor functions of infiltrating immune cells. We are currently evaluating the optimal viral immunotherapy for combination with TIDAL-01 to advance into clinical development.

Our History and Team

We were founded in 2015 with the goal of developing medicines to treat and cure patients with solid tumors. Our initial scientific and technological focus was built around developing novel oncolytic viral immunotherapies. In late 2020, we acquired an innovative TIL platform and capabilities to expand our portfolio of cancer immunotherapies. Our TIL-based technology now represents the foundational therapeutic modality driving our current pipeline, though we continue to explore the synergistic potential of combining these two technologies in the pursuit of our mission.

We have assembled a team with extensive experience in complex biologics, drug discovery and development, manufacturing, and business and commercial product development. We are led by our Chief Executive Officer, Sammy Farah, M.B.A, Ph.D., who has 20 years of scientific, business, and executive management experience in the biotechnology industry at Synthetic Genomics, Immune Design, Versant Ventures, and Merck. Our research organization is led by our Chief Scientific Officer, Stewart Abbot, Ph.D., who brings over 20 years of research and development experience in cell-based and immune-oncology products from Adicet, Fate, Celgene and GE Healthcare. Our clinical development and regulatory organization is led by our interim Chief Medical Officer, Michael Burgess, MBChB, Ph.D., who has more than 20 years of experience building research and development teams and leading strategy and execution of clinical development at SpringWorks Therapeutics, Bristol-Myers Squibb, Roche, and Eli Lilly. Vijay Chiruvolu, Ph.D., our interim Chief Technology Officer who leads our technical operations organization, holds over 27 years of relevant industry experience in process development, manufacturing, supply chain, and quality at Instil Bio, Kite Pharma/Gilead Sciences, Scios, Avigen, Hoffmann-La Roche, Johnson & Johnson, and Amgen, and was responsible for the manufacturing and process teams that worked towards regulatory approval of two cell therapy products, Yescarta and Tecartus. Our Chief Business Officer, Saryah Azmat, brings over 10 years of experience in biopharmaceutical business development, corporate strategy and capital formation at Bristol Myers Squibb and Putnam Associates. Our Chief Legal Officer, P. Joseph Campisi, Jr., Esq., holds over 30 years of experience in mergers and acquisitions, collaborations, and securities offerings and corporate governance at Scorpion, Bristol Myers Squibb, and Pillsbury Winthrop; and Venkat Ramanan, Ph.D., our Chief Financial Officer, holds over 20 years of experience in biopharmaceutical finance and operations at Seagen, Gilead, and Amgen.

Since our inception, we have raised $362.0 million in capital, including approximately $172.0 million from preferred stock financings and $190.0 million in non-dilutive payments from strategic partnerships. We are supported by a syndicate that includes entities affiliated with Versant Ventures, OrbiMed Private Investments VI, LP, entities affiliated with F-Prime Capital, and entities affiliated with FACIT Inc. Prospective investors should not rely on the investment decisions of our existing investors, as these investors may have different risk tolerances and have received their shares in prior offerings at prices lower than the price offered to the public in this offering. See the section titled “Certain Relationships and Related Party Transactions” for more information.

Our Strategy

Our mission is to develop new medicines to treat and cure patients with solid tumors using our next generation TIL therapy approach. We intend to achieve our mission by implementing the following strategies.

•

Advance our lead Selected TIL product candidate, TIDAL-01, for the treatment of solid tumors. We are developing TIDAL-01 for the potential treatment of a broad range of solid tumor types, and we are pursuing a clinical development strategy designed to demonstrate benefit in multiple indications. We have initiated a Phase 1b clinical trial that will evaluate TIDAL-01 in solid tumors where bulk TILs have demonstrated limited to no objective responses in clinical trials to date, including breast cancer, colorectal cancer, and uveal melanoma. Additionally, we have also initiated our investigator sponsored Phase 1 clinical trial in collaboration with Moffitt that will evaluate TIDAL-01 in multiple types of melanoma including cutaneous melanomas, an indication where bulk TILs have shown objective responses in clinical trials. We are very early in our development efforts, and as we make progress, if we obtain positive results of sufficient magnitude from one or both trials, we intend to discuss, receive guidance and the appropriate acceptance from the relevant regulatory agency(ies) to determine if we will be advancing TIDAL-01 into pivotal trials, which are trials that are intended to secure regulatory approval for a product candidate.

•

Develop TIDAL-02 and continue to build our pipeline of additional Selected TIL programs. We are expanding our portfolio by making modifications to our Selected TILs to streamline manufacturing and further enhance the quality and function of Selected TILs. This strategy is exemplified by our second Selected TIL program, TIDAL-02. This program is intended to employ a next generation rapid selection process, culture enhancements to improve and maintain TIL quality ex vivo, and/or functional gene edits to ensure durable enhancements to TIL quality and persistence in vivo, while minimizing dependance on exogenous IL-2 for in vivo proliferation. We intend to advance TIDAL-02 towards the clinic for the treatment of solid tumor indications that are distinct from and complementary to TIDAL-01, with the goal of moving into earlier lines of therapy. In addition to TIDAL-02, we have ongoing research efforts to further expand our pipeline of Selected TIL programs.

•

Leverage viral immunotherapies to further increase the activity of Selected TILs across multiple solid tumors. Given our oncolytic virus expertise and our proprietary viral immunotherapies, we believe we are strongly positioned to be a leading company in using viral immunotherapy to further increase the activity of our TIL therapies, if approved. We plan to advance our TIDAL-01 and viral immunotherapy combination strategy to further expand the breadth and depth of response of our Selected TILs across multiple solid tumors. We also plan to explore additional Selected TIL and viral immunotherapy combinations.

•

Commercialize and improve patient access to Selected TIL therapy through our CMC development expertise and manufacturing capabilities. We are expanding our in-house cell therapy process and analytical development capacity and capability, and in parallel assembling a network of external manufacturing and supply chain partners. We have designed a robust analytical characterization program to complement clinical development, support regulatory requirements and enable access to our Selected TILs for a broad range of patients with solid tumors. Our intent is that all early-clinical

stage Selected TIL product candidates are built upon a CMC foundation with clear line-of-sight to commercial viability, sequenced and staged appropriately with clinical progress.

•

Support existing and opportunistically explore future strategic partnerships and collaborations to maximize the potential of our programs. We are leveraging relationships with three academic collaborators, including a strategic partnership with Moffitt, and collaborations with the National Cancer Institute, or NCI, and Centre hospitalier de l’Université de Montreal, or CHUM, to help support development of our Selected TIL approach and pipeline. Our academic relationships are designed to enable us to tap into the deep expertise within these leading institutes that have decades of research and clinical experience in developing TIL therapies. We plan to continue to explore opportunistic collaborations with both academic and industry partners to extend our reach and maximize the potential of our programs.

Risks Affecting Our Business

Our business is subject to a number of risks, including risks that may prevent us from achieving our business objectives or may adversely affect our business, results of operations and financial condition that you should consider before making a decision to invest in our common stock. These risks are discussed more fully in the section titled “Risk Factors” beginning on page 16 of this prospectus, and include the following:

•

We have limited operating history, have incurred substantial net losses and anticipate that we will continue to incur net losses for the foreseeable future. We have no products approved for commercial sale, have never generated any revenue from product sales and may never be profitable.

•

We will require additional capital in addition to the proceeds from this offering to fund our operations, and if we fail to obtain necessary capital on acceptable terms, or at all, we will not be able to complete the development and future commercialization of our current and any future product candidates.

•

Our management, and our independent registered public accounting firm have concluded that there is substantial doubt as to our ability to continue as a going concern. As reflected in the audited consolidated financial statements and unaudited interim consolidated financial statements, each included elsewhere in this prospectus, we have incurred significant operating losses in the past, and we expect to continue to incur significant operating losses and negative cash flows for the foreseeable future. For the years ended December 31, 2022 and 2021, we reported a net loss of $30.8 million and a net income of $33.3 million, respectively. For the three months ended March 31, 2023 and 2022, we reported a net income of $0.1 million and a net loss of $12.6 million, respectively. Additionally, we will not receive any additional collaboration revenue under the research, option, and license agreement, or the AbbVie Agreement, with AbbVie Biotechnology Ltd., or AbbVie, or the discovery, collaboration and license agreement, or the Takeda Agreement, with Millennium Pharmaceuticals, Inc. (also known as Takeda Oncology), a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited, or Takeda, in the future because these agreements have been terminated. Our ability to continue as a going concern is subject to our ability to obtain sufficient financing. If we cannot continue as a going concern, we may have to liquidate our assets and may receive less than the value at which those assets are carried on our combined financial statements, and it is likely that our stockholders may lose some or all of their investment in us. After this offering, we may not raise the funding we require such that substantial doubt about our ability to continue as a going concern continues. If we seek additional financing to fund our business activities in the future and there remains substantial doubt about our ability to continue as a going concern, investors or other financing sources may be unwilling to provide additional

funding on commercially reasonable terms or at all. If we cannot continue as a going concern, our stockholders may lose some or all of their investment in us.

•

Our business is highly dependent on the success of our lead Selected TIL product candidate TIDAL-01, as well as our other current and any future product candidates. All of our product candidates will require significant additional preclinical or clinical development before we are able to seek regulatory approval for and launch a product commercially.

•

If we fail to develop and receive approval for our existing or any additional future product candidates, our commercial opportunity could be limited which could adversely affect our business, results of operations and financial condition.

•

Unfavorable global economic conditions, including any adverse macroeconomic conditions or geopolitical events, including the COVID-19 pandemic, the conflict between Ukraine and Russia, and recent bank failures affecting the financial services industry, could adversely affect our business, financial condition, results of operations or liquidity, either directly or through adverse impacts on certain of the third parties on which we rely to conduct certain aspects of our preclinical studies or clinical trials.

•

Clinical development involves a lengthy and expensive process, with uncertain outcomes. We may incur significant costs and/or experience delays in completing, or ultimately be unable to complete, the development of our current and future product candidates, including our lead product candidates.

•

Preclinical development is uncertain. Our preclinical programs may experience delays or generate unfavorable data, and may never advance to clinical trials, which would adversely affect our ability to obtain regulatory approvals or commercialize these programs on a timely basis or at all, and any of these events would adversely affect our business, results of operations and financial condition.

•

Our product candidates are based on a novel approach to the treatment of cancer, which makes it difficult to predict the time and cost of product candidate development.

•

The manufacture of our product candidates is complex, and we may encounter difficulties in production, particularly with respect to process development, quality control, or scaling-up of any future manufacturing capabilities. If we, or any of our third-party manufacturers encounter such difficulties, our ability to provide supply of our product candidates for clinical trials or our products for patients, if approved, could be delayed or stopped, or we may be unable to maintain a commercially viable cost structure.

•

We face significant competition and if we fail to compete effectively, our business, results of operations and financial condition could be adversely affected.

•

Negative developments in the fields of immuno-oncology and TIL-based immunotherapy could damage public perception of our product candidates and adversely affect our business, results of operations and financial condition.

•

We have relied and expect to continue to rely on third parties to conduct certain aspects of our preclinical studies, to conduct our clinical trials and to conduct investigator sponsored clinical trials of our product candidates. If these third parties do not successfully carry out their contractual duties or meet expected deadlines, comply with regulatory requirements or terminate the relationship, we may not be able to obtain regulatory approval of or commercialize any potential product candidates.

•

The regulatory approval process for our product candidates in the United States, and other jurisdictions is currently uncertain and will be lengthy, time-consuming and inherently unpredictable, and we may experience significant delays in the clinical development and regulatory approval, if any, of our product candidates.

•

Our success depends in part on our ability to protect our intellectual property. It is difficult and costly to protect our proprietary rights and technology, and we may not be able to ensure their protection.

•

Intellectual property rights do not necessarily address all potential threats to our business.

•

No public market for our common stock currently exists, and we do not know whether an active, liquid and orderly trading market will develop for our common stock, or what the market price of our common stock will be, and as a result it may be difficult for you to sell your shares of our common stock.

•

Sales of a substantial number of shares of our common stock in the public market could cause our stock price to fall.

•

Pursuant to a letter agreement, or the Takeda Letter Agreement, dated June 29, 2023, Takeda has agreed to submit a non-binding indication of interest to participate in this offering by purchasing at the public offering price per share the number of shares of our common stock with an aggregate value of $8.0 million or such lesser amount as determined by us in our sole discretion, or the Takeda IPO Shares. The Takeda IPO Shares will not be subject to a lock-up agreement. Any transfers or sales of the Takeda IPO Shares may cause the price of our common stock to decline. See the section titled “Certain Relationships and Related Party Transactions—Public Offering Participation Rights.”

Our Corporate Information

Turnstone Biologics Inc. was incorporated as a Canadian corporation on March 27, 2014. On December 13, 2018, we incorporated Turnstone Biologics Corp., a corporation under the laws of the State of Delaware. On December 14, 2018, we completed a reorganization from Canada to the United States, which we refer to as the Reorganization. In connection with the Reorganization, all of the shareholders of Turnstone Canada exchanged their shares in Turnstone Canada for shares of our new incorporated Delaware entity, as a result of which Turnstone Canada became our wholly owned subsidiary. Our principal executive offices are located at 9310 Athena Circle, Suite 300, La Jolla, California 92037, and our telephone number is (347) 897-5988. Our website address is www.turnstonebio.com. The information contained on, or accessible through, our website is not incorporated by reference into this prospectus, and you should not consider any information contained on, or that can be accessed through, our website as part of this prospectus or in deciding whether to purchase our common stock.

We own various U.S. federal trademark applications and unregistered trademarks, including our company name. All other trademarks or trade names referred to in this prospectus are the property of their respective owners. Solely for convenience, the trademarks and trade names in this prospectus are referred to without the symbols ^® and ^™, but such references should not be construed as any indicator that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto.

Implications of Being an Emerging Growth Company and a Smaller Reporting Company

We qualify as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. An emerging growth company may take advantage of relief from certain reporting requirements and other burdens that are otherwise applicable generally to public companies. These provisions include:

•

reduced obligations with respect to financial data, including presenting only two years of audited financial statements and only two years of selected financial data in this prospectus;

•

an exception from compliance with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended, or the Sarbanes-Oxley Act;

•

reduced disclosure about our executive compensation arrangements in our periodic reports, proxy statements and registration statements, including the registration statement of which this prospectus forms a part;

•

exemptions from the requirements of holding non-binding advisory votes on executive compensation or golden parachute arrangements; and

•

an exemption from compliance with the requirements of the Public Company Accounting Oversight Board regarding the communication of critical audit matters in the auditor’s report on the financial statements.

We may take advantage of these provisions for up to five years or such earlier time that we no longer qualify as an emerging growth company. We would cease to qualify as an emerging growth company on the date that is the earliest of (i) the last day of the fiscal year in which we have total annual gross revenue of $1.235 billion or more; (ii) the last day of our fiscal year following the fifth anniversary of the date of the completion of this offering; (iii) the date on which we have issued more than $1.0 billion in nonconvertible debt during the previous three years; or (iv) the date on which we are deemed to be a “large accelerated filer” under the rules of the U.S. Securities and Exchange Commission, or SEC, which means the market value of our common stock that is held by non-affiliates exceeds $700.0 million as of the prior June 30th. We may choose to take advantage of some but not all of these reduced reporting burdens. For example, we may take advantage of the exemption from auditor attestation on the effectiveness of our internal control over financial reporting. To the extent that we take advantage of these reduced reporting burdens, the information that we provide stockholders may be different than you might obtain from other public companies in which you hold equity interests.

In addition, under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards until such time as those standards apply to private companies. We have elected to avail ourselves of this exemption, and, as a result, our operating results and financial statements may not be comparable to the operating results and financial statements of companies who have adopted the new or revised accounting standards.

We are also a “smaller reporting company” as defined in the Securities Exchange Act of 1934, as amended, or the Exchange Act. We may continue to be a smaller reporting company even after we are no longer an emerging growth company. We may take advantage of certain of the scaled disclosures available to smaller reporting companies and will be able to take advantage of these scaled disclosures for so long as our common stock held by non-affiliates is less than $250.0 million measured on the last business day of our second fiscal quarter, or our annual revenue is less than $100.0 million during the most recently completed fiscal year and our common stock held by non-affiliates is less than $700.0 million measured on the last business day of our second fiscal quarter.

The Offering

Common stock offered by us

5,800,000 shares.

Option to purchase additional shares

We have granted the underwriters an option, exercisable for 30 days after the date of this prospectus, to purchase up to 870,000 additional shares from us.

Common stock to be outstanding immediately after this offering

21,322,015 shares (or 22,192,015 shares if the underwriters exercise their option to purchase additional shares of common stock in full).

Reserved share program

At our request, an affiliate of BofA Securities, Inc., a participating underwriter, has reserved for sale, at the initial public offering price, up to 5.0% of the shares offered by this prospectus for sale to some of our directors, officers, employees, and certain other related parties to us. If these persons purchase reserved shares it will reduce the number of shares available for sale to the general public. Any reserved shares that are not so purchased will be offered by the underwriters to the general public on the same terms as the other shares offered by this prospectus. For more information, see “Underwriting.”

Use of proceeds

We estimate that the net proceeds from this offering will be approximately $65.8 million (or approximately $76.3 million if the underwriters exercise their option to purchase additional shares in full), assuming an initial public offering price of $13.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. We intend to use the net proceeds from this offering, together with our existing cash, cash equivalents and short-term investments, as follows: (i) approximately $70 million to $75 million to fund the continued development of TIDAL-01 in our two Phase 1 clinical trials for the treatment of breast cancer, colorectal cancer, uveal melanoma and other non-cutaneous and cutaneous melanomas, including through initial clinical data update in mid-2024 and continued development into the second quarter of 2025, (ii) approximately $15 million to $20 million to advance our TIDAL-02 program through candidate declaration and TIDAL-01 and viral immunotherapy combination program through an investigational new drug application, or IND, and (iii) the remaining proceeds, if any, for working capital and general corporate purposes. We may also use a portion of the remaining net proceeds and our existing cash, cash equivalents and short-term investments, to in-license, acquire, or invest in complementary businesses, technologies, products, or assets. However, we have no current commitments or obligations to do so. See the section titled “Use of Proceeds.”

Risk factors

See the section titled “Risk Factors” beginning on page 16 and the other information included in this prospectus for a discussion of factors you should consider carefully before deciding to invest in our common stock.

Proposed Nasdaq Global Market symbol

“TSBX”

The number of shares of our common stock to be outstanding after this offering is based on 15,522,015 shares of our common stock outstanding as of March 31, 2023, after giving effect to the conversion of all outstanding shares of our convertible preferred stock into 12,493,879 shares of our common stock in connection with the closing of this offering, and excludes:

•

2,495,301 shares of our common stock issuable upon the exercise of outstanding stock options as of March 31, 2023, with a weighted-average exercise price of $8.86 per share;

•

186,043 shares of our common stock issuable upon the exercise of outstanding stock options granted subsequent to March 31, 2023, with a weighted-average exercise price of $16.53 per share;

•

275,163 shares of our common stock reserved for future issuance to Moffitt contingent on the achievement of certain clinical and regulatory milestones pursuant to our Alliance Agreement (as defined below) with Moffitt;

•

2,722,887 shares of our common stock reserved for future issuance under our 2023 Equity Incentive Plan, or 2023 Plan, which will become effective upon the execution of the underwriting agreement for this offering, as well as any automatic increases in the number of shares of common stock reserved for future issuance under this plan; and

•

222,287 shares of our common stock reserved for future issuance under our 2023 Employee Stock Purchase Plan, or ESPP, which will become effective upon the execution of the underwriting agreement for this offering, as well as any automatic increases in the number of shares of common stock reserved for future issuance under this plan.

Unless otherwise indicated, this prospectus reflects and assumes the following:

•

the conversion of all outstanding shares of our convertible preferred stock into an aggregate of 12,493,879 shares of our common stock immediately prior to the closing of this offering;

•

a 1-for-7.9872 reverse stock split of our common stock effected on July 14, 2023;

•

no exercise of the outstanding options described above;

•

no exercise by the underwriters of their option to purchase up to 870,000 additional shares of our common stock; and

•

the filing and effectiveness of our amended and restated certificate of incorporation immediately following the closing of this offering and the adoption of our amended and restated bylaws immediately prior to the closing of this offering.

Summary Consolidated Financial Data

The following tables set forth our summary financial data for the periods and as of the dates indicated. We have derived the summary consolidated statements of operations and comprehensive income (loss) data for the years ended December 31, 2022 and 2021 from our audited consolidated financial statements included elsewhere in this prospectus. We have derived the summary consolidated statements of operations and comprehensive income (loss) data for the three months ended March 31, 2023 and 2022 and the summary consolidated balance sheet data as of March 31, 2023 from our unaudited interim consolidated financial statements to be included elsewhere in this prospectus. Our historical results are not necessarily indicative of the results that should be expected in the future, and the consolidated statements of operations and comprehensive income (loss) data for the three months ended March 31, 2023 are not necessarily indicative of the results to be expected for the full year ending December 31, 2023 or any other period. You should read the following summary consolidated financial data together with our consolidated financial statements and the related notes included elsewhere in this prospectus and the information in the section titled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” contained elsewhere in this prospectus.


	Year Ended December 31,					Three Months Ended March 31,
	2022			2021		2023			2022
						(unaudited)
Consolidated Statements of Operations and Comprehensive Income (Loss) Data (in thousands):
Collaboration revenue	$	73,300		$	101,293	$	19,306		$	10,718
Operating expenses:
Research and development	$	86,703		$	54,754	$	15,668		$	18,701
General and administrative		18,223			13,546		4,032			4,698

Total operating expenses		104,926			68,300		19,700			23,399

Income (loss) from operations		(31,626	)		32,993		(394	)		(12,681	)
Other income (expense), including provision for income taxes, net		792			276		462			65

Net income (loss)	$	(30,834	)	$	33,269	$	68		$	(12,616	)

Net income (loss) per share of common stock attributable to common stockholders, basic⁽¹⁾	$	(12.49	)	$	1.62	$	—		$	(5.56	)

Net income (loss) per share of common stock attributable to common stockholders, diluted⁽¹⁾	$	(12.49	)	$	1.29	$	—		$	(5.56	)

Weighted-average number of shares used in computing net earnings, basic		2,484,569			2,149,550		2,786,017			2,279,287

Weighted-average number of shares used in computing net earnings, diluted		2,484,569			2,702,347		2,786,017			2,279,287

Pro forma net income (loss) per share of common stock attributable to common stockholders, basic and diluted⁽²⁾	$	(2.06)				$	0.00

Pro forma weighted-average shares of common stock outstanding, basic⁽²⁾		14,978,444					15,279,895
Pro forma weighted-average shares of common stock outstanding, diluted⁽²⁾		14,978,444					15,718,491

(1)

See Note 12 to our audited consolidated financial statements and Note 12 to our unaudited interim consolidated financial statements, each included elsewhere in this prospectus, for an explanation of the method used to calculate basic and diluted net loss per share and the weighted-average number of shares used in the computation of the per share amounts.

(2)

Pro forma basic and diluted net income (loss) per share of common stock attributable to common stockholders has been prepared to give effect to adjustments to our capital structure arising in connection with the completion of this offering and is calculated by dividing pro forma net income (loss) per share of common stock attributable to common stockholders by the pro forma weighted-average shares of common stock outstanding for the period. The unaudited pro forma net income (loss) attributable to common stockholders used in the calculation of unaudited pro forma basic and diluted net income (loss) per share of common stock attributable to common stockholders is equal to net income (loss) attributable to common stockholders. The unaudited pro forma basic and diluted weighted-average common shares outstanding used in the calculation of unaudited pro forma basic and diluted net income (loss) per share for the three months ended March 31, 2023 and for the year ended December 31, 2022 have been prepared to reflect the conversion of all of the outstanding

shares of our convertible preferred stock into an aggregate of 12,493,879 shares of our common stock as if the offering had occurred on January 1, 2022.


	As of March 31, 2023
	Actual			Pro Forma⁽¹⁾			Pro Forma As Adjusted⁽²⁾⁽³⁾
	(unaudited)
Balance Sheet Data (in thousands):
Cash, cash equivalents and short-term investments	$	63,969		$	63,969		$	129,782
Working capital⁽⁴⁾		60,031			60,031			125,844
Total assets		92,263			92,263			158,076
Redeemable convertible preferred stock		171,964			—			—
Accumulated deficit		(121,490	)		(121,490	)		(121,490	)
Total stockholders’ (deficit) equity		(100,223	)		71,741			137,554

(1)

Pro forma balance sheet data reflects (i) the conversion of all outstanding shares of our convertible preferred stock into an aggregate of 12,493,879 shares of common stock and the related reclassification of the carrying value of our convertible preferred stock to permanent equity in connection with the closing of this offering and (ii) the filing and effectiveness of our amended and restated certificate of incorporation that will be in effect immediately following the closing of this offering.

(2)

Pro forma as adjusted balance sheet data reflects the pro forma items described immediately above and our issuance and sale of shares of common stock in this offering at an assumed initial public offering price of $13.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

(3)

Pro forma as adjusted balance sheet data is illustrative only and will change based on the actual initial public offering price and other terms of this offering determined at pricing. Each $1.00 increase or decrease in the assumed initial public offering price of $13.00 per share, the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease, as applicable, each of our pro forma as adjusted cash, cash equivalents and short-term investments, working capital, total assets and total stockholders’ (deficit) equity by approximately $5.4 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. We may also increase or decrease the number of shares we are offering. Each 1,000,000 share increase or decrease in the number of shares offered by us would increase or decrease, as applicable, each of our pro forma as adjusted cash, cash equivalents and short-term investments, working capital, total assets and total stockholders’ (deficit) equity by approximately $12.1 million, assuming that the assumed initial offering price to the public remains the same, and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

(4)	We define working capital as current assets less current liabilities. See our consolidated financial statements and the related notes included elsewhere in this prospectus for further details regarding our current assets and current liabilities.

RISK FACTORS

Investing in our common stock involves a high degree of risk. You should carefully consider the risks described below, as well as the other information in this prospectus, including our consolidated financial statements and the related notes, and the section titled “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” before deciding whether to invest in our common stock. The occurrence of any of the events or developments described below could adversely affect our business, results of operations and financial condition. In any such event, the market price of our common stock could decline, and you may lose all or part of your investment. Additional risks and uncertainties not presently known to us or that we currently believe to be immaterial also may impair our business, results of operations and financial condition.

Risks Related to Our Business

We are a clinical stage biotechnology company with a limited operating history. We were formed in 2014 and we have devoted substantially all of our efforts and financial resources to organizing and staffing our company, business planning, raising capital, discovering product candidates and securing related intellectual property rights, and conducting research and development activities for our Selected TIL programs and product candidates. Consequently, we have no meaningful operations upon which to evaluate our business and predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history or a history of successfully developing and commercializing program candidates. Investment in biotechnology product development is highly speculative because it entails substantial upfront capital expenditures and significant risk that any potential product candidate will fail to demonstrate adequate effect or an acceptable safety profile, gain regulatory approval and become commercially viable. We have not yet demonstrated the ability to progress any product candidate through clinical trials, we have no products approved for commercial sale and we have not generated any revenue from product sales to date. We continue to incur significant research and development and other expenses related to our ongoing operations. As a result, we are not profitable and we have incurred overall net losses since our inception through March 31, 2023. For the years ended December 31, 2022 and 2021, we reported a net loss of $30.8 million and a net income of $33.3 million, respectively. For the three months ended March 31, 2023 and 2022, we reported a net income of $0.1 million and a net loss of $12.6 million, respectively. As of December 31, 2022 and March 31, 2023, we had an accumulated deficit of $121.6 million and $121.5 million, respectively. Additionally, we will not receive any additional collaboration revenue under the AbbVie Agreement or the Takeda Agreement in the future because these agreements have been terminated. We expect to continue to incur significant losses for the foreseeable future, and we expect these losses to increase as we continue our research and development of our Selected TIL programs, and seek regulatory approvals for our product candidates.

We anticipate that our expenses will increase substantially if, and as, we:

•

advance the development of our lead Selected TIL product candidate TIDAL-01 through two Phase 1 clinical trials and, if the results are favorable, into further clinical development;

•

actively advance our other preclinical pipeline programs, including TIDAL-02, our next Selected TIL program and our TIDAL-01 and viral immunotherapy combination program;

•

seek regulatory approvals for any product candidates that successfully complete clinical trials, if any;

•

increase the amount of research and development activities to identify and develop Selected TIL product candidates;

•

hire additional clinical, quality control and scientific personnel;

•

expand our operational, financial and management systems and increase personnel, including personnel to support our clinical development, manufacturing and commercialization efforts and our operations as a public company;

•

maintain, expand and protect our intellectual property portfolio;

•

expand our external manufacturing relationships;

•

oversee and maintain our manufacturing infrastructure;

•

establish a sales, marketing, medical affairs and distribution infrastructure to commercialize any products for which we may obtain marketing approval and intend to commercialize on our own or jointly with third parties; and

•

invest in or in-license enabling technologies.

To become and remain profitable, we and any current or potential future collaborators must develop and eventually commercialize products with significant market potential. This will require us to be successful in a range of challenging activities, including completing preclinical studies and clinical trials, obtaining marketing approval for product candidates, manufacturing, marketing and selling products if we obtain marketing approval, obtaining market acceptance for such products and satisfying any post-marketing requirements. We may never succeed in any or all of these activities and, even if we do, we may never generate revenue that is significant or large enough to achieve profitability. If we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would decrease the value of our company and the price or of common stock, and could impair our ability to raise capital, maintain our research and development efforts, expand our business or continue our operations. A decline in the value of our company also could cause you to lose all or part of your investment.

Even if we succeed in commercializing one or more of our product candidates, we will continue to incur substantial research and development and other expenditures to develop and market additional product candidates. We also may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. The size of our future net losses will depend, in part, on the rate of future growth of our expenses and our ability to generate revenue. Our prior losses and expected future losses have had and will continue to have an adverse effect on our stockholders’ (deficit) equity and working capital.

Our operations have consumed substantial amounts of cash since our inception. We expect to continue to spend substantial amounts of cash to conduct further research and development, preclinical studies and clinical trials of our current and future product candidates, to seek regulatory approvals for our product candidates and to launch and commercialize any products if we receive regulatory approval.

We have initiated two Phase 1 clinical trials for our lead Selected TIL product candidate, TIDAL-01, including a multi-site trial for the treatment of breast cancer, colorectal cancer, and uveal melanoma, and an investigator sponsored trial with Moffitt in both cutaneous and non-cutaneous melanomas. We intend to provide an initial clinical update across these two trials in mid-2024. We are also developing TIDAL-02, our next Selected TIL program, which is currently in preclinical development and we intend to evaluate the combination of TIDAL-01 with viral immunotherapy. We are currently evaluating the optimal viral immunotherapy for combination with TIDAL-01 to advance into clinical development.

As of March 31, 2023, we had approximately $64.0 million in cash, cash equivalents and short-term investments. Based on our current operating plan, we expect that the net proceeds from this offering, together with our cash, cash equivalents and short-term investments, will enable us to fund our operations into the second quarter of 2025. However, our future capital requirements and the period for which our existing resources will support our operations may vary significantly from what we expect, and we will in any event require additional capital in order to complete clinical development of any of our current programs. Our monthly spending levels will vary based on new and ongoing development and corporate activities. Because the length of time and activities associated with development of our programs and product candidates is highly uncertain, we are unable to estimate the actual funds we will require for development and any approved marketing and future commercialization activities, if any. Our future capital requirements will depend on many factors, including:

•

the costs of conducting clinical trials;

•

the progress of preclinical development for our programs and clinical trials of our current earlier-stage product candidates;

•

the costs of manufacturing;

•

the scope, progress, results and costs of discovery, preclinical development, laboratory testing and clinical trials for other potential product candidates we may develop, if any;

•

the costs, timing and outcome of regulatory review of our product candidates;

•

our ability to establish and maintain collaborations and partnerships on favorable terms, if at all;

•

the achievement of milestones or occurrence of other developments that trigger payments to us or by us under any collaboration agreements we might have at such time;

•

the costs of preparing, filing and prosecuting patent applications, obtaining, maintaining and enforcing our intellectual property rights and defending intellectual property-related claims;

•

our headcount growth and associated costs as we expand our business operations and research and development activities;

•

the cost of operating as a public company;

•

our ability to mitigate the impact of adverse macroeconomic conditions or geopolitical events, including the COVID-19 pandemic, the ongoing conflict between Ukraine and Russia, recent bank failures or other factors on our preclinical and clinical development or operations;

•

the costs and timing of future commercialization activities, if any, including product sales, marketing, manufacturing and distribution, if we receive marketing approval for any of our product candidates;

•

our ability to achieve sufficient market acceptance, adequate coverage and reimbursement from third-party payors and adequate market share; and

•

the amount of revenue, if any, received from commercial sales of our product candidates, if any of our product candidates receive marketing approval.

We do not have any committed external source of funds or other support for our development efforts and additional funding may not be available on acceptable terms, or at all. Market volatility resulting from

adverse macroeconomic conditions or geopolitical events, including the COVID-19 pandemic, the ongoing conflict between Ukraine and Russia, recent bank failures or other factors may further adversely impact our ability to access capital as and when needed. Until we can generate sufficient product or royalty revenue to finance our cash requirements, which we may never do, we expect to finance our future cash needs through a combination of public or private equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other arrangements. If we raise additional funds through public or private equity offerings, the terms of these securities may include liquidation or other preferences that adversely affect our stockholders’ rights. Further, to the extent that we raise additional capital through the sale of common stock or securities convertible or exchangeable into common stock, your ownership interest will be diluted. In addition, any debt financing may subject us to fixed payment obligations and covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional capital through marketing and distribution arrangements or other collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish certain valuable rights to our product candidates, technologies, future revenue streams or research programs or grant licenses on terms that may not be favorable to us. We also could be required to seek collaborators for our current or future product candidates at an earlier stage than otherwise would be desirable or relinquish our rights to product candidates or technologies that we otherwise would seek to develop or commercialize ourselves. If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we may need to significantly delay, scale back or discontinue the development or future commercialization of one or more of our product candidates, if approved, or one or more of our other research and development initiatives and we may need to undertake additional workforce reductions or restructuring activities in the future. Any of the above events could adversely affect our business, results of operations and financial condition and cause the price of our common stock to decline.

Our management and our independent registered public accounting firm have concluded that there is substantial doubt as to our ability to continue as a going concern. If we cannot continue as a going concern, our stockholders may lose some or all of their investment in our company.

Our audited consolidated financial statements and unaudited interim consolidated financial statements, each included elsewhere in this prospectus, were prepared assuming that we will continue as a going concern. The going concern basis of presentation assumes that we will continue in operation for the foreseeable future and will be able to realize our assets and satisfy our liabilities in the normal course of business and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from our inability to continue as a going concern. As reflected in the audited consolidated financial statements and unaudited interim consolidated financial statements, each included elsewhere in this prospectus, we have incurred significant operating losses in the past, and we expect to continue to incur significant operating losses and negative cash flows for the foreseeable future. For the years ended December 31, 2022 and 2021, we reported a net loss of $30.8 million and a net income of $33.3 million, respectively. For the three months ended March 31, 2023 and 2022, we reported a net income of $0.1 million and a net loss of $12.6 million, respectively. As of December 31, 2022 and March 31, 2023, we had an accumulated deficit of $121.6 million and $121.5 million, respectively. Additionally, we will not receive any additional collaboration revenue under the AbbVie Agreement or the Takeda Agreement in the future because these agreements have been terminated. As of March 31, 2023, our management concluded that, based on our expected operating losses and negative cash flows, there is substantial doubt about our ability to continue as a going concern for the 12 months after the date the unaudited interim consolidated financial statements were issued. Our ability to continue as a going concern is subject to our ability to obtain sufficient financing. If we cannot continue as a going concern, we may have to liquidate our assets and may receive less than the value at which those assets are carried on our combined financial statements, and it is likely that our stockholders may lose some or all of their investment in us. After this offering, we may not raise the funding we require such that substantial doubt about our ability to continue as a going concern continues. If we seek additional financing to fund our business activities in the future and there remains substantial doubt about our ability to continue as a going concern, investors or other financing sources may be unwilling to provide additional funding on commercially reasonable

terms or at all. If we cannot continue as a going concern, our stockholders may lose some or all of their investment in us.

We are very early in our development efforts. If TIDAL-01 or any future product candidates encounter safety or efficacy problems, manufacturing failures, development delays or regulatory issues or other problems, our development plans and business may be significantly harmed.

Our current and any future product candidates will require additional preclinical or clinical development, regulatory review and approval in one or more jurisdictions, substantial investment, and access to sufficient commercial manufacturing capacity and significant marketing efforts before we can generate any revenue from product sales. We may not have the financial resources to continue development of, or to modify existing or enter into new collaborations for, any product candidate if we experience any issues that delay or prevent regulatory approval of, or our ability to commercialize, our product candidates, including:

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negative or inconclusive results from our preclinical studies or clinical trials or the clinical trials of others for product candidates similar to ours, leading to a decision or requirement to conduct additional preclinical testing or clinical trials or abandon a program;

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product-related side effects experienced by subjects in our clinical trials or by individuals using products or immunotherapies similar to our product candidates;

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delays in submitting INDs or comparable foreign applications or delays or failure in obtaining the necessary authorizations or approvals from regulators to commence a clinical trial, or a suspension or termination of a clinical trial once commenced;

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conditions imposed by the FDA or comparable foreign regulatory authorities regarding the scope or design of our clinical trials;

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delays in enrolling subjects in clinical trials;

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high drop-out rates of subjects from clinical trials;

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inadequate supply or quality of product candidates or other materials necessary for the conduct of our clinical trials;

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greater than anticipated clinical trial costs;

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poor effectiveness of or safety issues associated with our product candidates during clinical trials;

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unfavorable FDA or comparable foreign regulatory authorities’ inspection and review of a clinical trial site;

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failure of our third-party contractors or investigators to comply with regulatory requirements or otherwise meet their contractual obligations in a timely manner, or at all;

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potential disruptions caused by the COVID-19 pandemic or other health pandemics or epidemics, including difficulties in initiating clinical sites, enrolling and retaining participants, diversion of healthcare resources away from clinical trials, travel or quarantine policies that may be implemented, and other factors;

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delays and changes in regulatory requirements, policy and guidelines, including the imposition of additional regulatory oversight around clinical testing generally or with respect to our technology in particular;

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varying interpretations of data by the FDA or comparable foreign regulatory authorities;

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manufacturing failures, including our TIL selection process, resulting in a less effective product candidate in the tumor indications we are pursuing; or

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unsuccessful improvements to our internal manufacturing processes.

The occurrence of any of the above events could adversely affect our business, results of operations and financial condition.

Developing, obtaining marketing approval for, and commercializing any product candidates will require substantial additional funding beyond the net proceeds of this offering and will be subject to the risks of failure inherent in medical product development. We may not be able to successfully advance any of our existing product candidates or any additional product candidates through the development process.

Even if we obtain approval from the FDA or comparable foreign regulatory authorities to market our existing or any additional product candidates for the treatment of solid tumors or any other indication, any such product candidates may not be successfully commercialized, widely accepted in the marketplace, or more effective than other commercially available alternatives. If we are unable to successfully develop and commercialize our existing or any additional product candidates, our commercial opportunity may be limited and our business, results of operations and financial condition may be adversely affected.

Our results of operations could be adversely affected by general conditions in the global economy and in the global financial markets. Global economic and business activities continue to face widespread uncertainties, and global credit and financial markets have experienced extreme volatility and disruptions in the past several years, including severely diminished liquidity and credit availability, rising inflation and monetary supply shifts, rising interest rates, labor shortages, declines in consumer confidence, declines in economic growth, increases in

unemployment rates, recession risks, and uncertainty about economic and geopolitical stability. A severe or prolonged economic downturn, or additional global financial or political crises, could result in a variety of risks to our business, including delayed clinical trials or preclinical studies, delayed approval of our product candidates, delayed ability to obtain patents and other intellectual property protection, weakened demand for our product candidates, if approved, or our ability to raise additional capital when needed on acceptable terms, if at all. The extent of the impact of these conditions on our operational and financial performance, including our ability to execute our business strategies and initiatives in the expected timeframe, as well as that of third parties upon whom we rely, will depend on future developments which are uncertain and cannot be predicted. A weak or declining economy also could strain our suppliers, possibly resulting in supply disruption. Any of the foregoing could harm our business and we cannot anticipate all of the ways in which the current economic climate and financial market conditions could adversely impact our business. Furthermore, our stock price may decline due in part to the volatility of the stock market and the general economic downturn.

Actual events involving limited liquidity, defaults, non-performance or other adverse developments that affect financial institutions, transactional counterparties or other companies in the financial services industry or the financial services industry generally, or concerns or rumors about any events of these kinds or other similar risks, have in the past and may in the future lead to market-wide liquidity problems. For example, on March 10, 2023, Silicon Valley Bank was closed by the California Department of Financial Protection and Innovation, which appointed the Federal Deposit Insurance Corporation, or FDIC, as receiver. Similarly, on March 12, 2023, Signature Bank and Silvergate Capital Corp. were each swept into receivership, and on May 1, 2023, First Republic Bank was also swept into receivership. Although a statement by the Department of the Treasury, the Federal Reserve and the FDIC indicated that all depositors of Silicon Valley Bank would have access to all of their money after only one business day of closure, including funds held in uninsured deposit accounts, borrowers under credit agreements, letters of credit and certain other financial instruments with Silicon Valley Bank, Signature Bank or any other financial institution that is placed into receivership by the FDIC may be unable to access undrawn amounts thereunder. If any of the banks which hold our cash deposits were to be placed into receivership, we may be unable to access such funds. As of March 31, 2023, all of our cash on deposit was maintained at two financial institutions in the United States, and our current deposits are in excess of federally insured limits. If further failures in financial institutions occur where we hold deposits, we could experience additional risk. Any such loss or limitation on our cash, cash equivalents and short-term investments would adversely affect our business. In addition, if any of the third parties on which we rely to conduct certain aspects of our preclinical studies or clinical trials are unable to access funds pursuant to such instruments or lending arrangements with such a financial institution, such parties’ ability to fulfill their obligations to us could be adversely affected.

If we engage in future acquisitions or strategic partnerships, this may increase our capital requirements, dilute our stockholders, cause us to incur debt or assume contingent liabilities, and subject us to other risks.

We may evaluate various acquisitions and strategic partnerships, including licensing or acquiring complementary products, intellectual property rights, technologies or businesses. Any potential acquisition or strategic partnership may entail numerous risks, including:

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increased operating expenses and cash requirements;

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the assumption of additional indebtedness, contractual obligations or contingent liabilities;

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the issuance of our equity securities;

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assimilation of operations, intellectual property and products of an acquired company, including difficulties associated with integrating new personnel;

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the diversion of our management’s attention from our existing product programs and initiatives in pursuing such a strategic merger or acquisition;

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retention of key employees, the loss of key personnel, and uncertainties in our ability to maintain key business relationships;

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risks and uncertainties associated with the other party to such a transaction, including the prospects of that party, their regulatory compliance status, and their existing products or product candidates and marketing approvals; and

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our inability to generate revenue from acquired technology and/or products sufficient to meet our objectives in undertaking the acquisition or even to offset the associated acquisition and maintenance costs.

In addition, if we undertake acquisitions, we may issue dilutive securities, assume or incur debt obligations, incur large one-time expenses and acquire intangible assets that could result in significant future amortization expense. Moreover, we may not be able to locate suitable acquisition opportunities and this inability could impair our ability to grow or obtain access to technology or products that may be important to the development of our business. Any of the foregoing may adversely affect our business, results of operations and financial condition.

We may not realize the expected benefits from our recent workforce reductions and it could result in total costs and expenses that are greater than expected and could disrupt our business.

In October 2022, we implemented a plan to consolidate our operations, which included a move to San Diego, California and a reduction in our workforce. In addition, in June 2023, we conducted an additional reduction in our workforce. The changes to our operations and the reductions in workforce may yield unintended consequences and costs, such as the loss of institutional knowledge and expertise, attrition beyond our intended reductions in force, and a reduction in morale among our remaining employees, all of which may have an adverse effect on our development activities, our business, results of operations or financial condition. If we are unable to realize the expected operational efficiencies, our business, results of operations and financial condition would be adversely affected. In addition, to the extent we do not realize such anticipated operational efficiencies, we may need to undertake additional workforce reductions or restructuring activities in the future. Furthermore, our reductions in force may be disruptive to our operations. For example, our workforce reductions could yield unanticipated consequences, such as attrition beyond planned staff reductions, increased difficulties in our day-to-day operations and reduced employee morale. If employees who were not affected by the reductions in force seek alternative employment, this could result in our seeking contractor support at unplanned additional expense or harm our productivity. Our workforce reductions could also harm our ability to attract and retain qualified management, scientific, clinical, and manufacturing personnel who are critical to our business. Any failure to attract or retain qualified personnel could prevent us from successfully developing our potential product candidates. We may also discover that the reductions in workforce could make it difficult for us to pursue new opportunities and initiatives and require us to hire qualified replacement personnel, which may require us to incur additional and unanticipated costs and expenses. Our failure to successfully accomplish any of the above activities and goals may have a material adverse impact on our business, results of operations and financial condition.

Our ability to use our net operating loss carryforwards to offset future income could be subject to limitation.

As of December 31, 2022, we had approximately $2.3 million of U.S. federal and $1.0 million of state net operating loss, or NOL, carryforwards. Our U.S. federal NOL carryforwards can be carried forward indefinitely, but use of such carryforwards is limited to 80% of taxable income. If not utilized, our state NOL carryforwards will begin to expire at various dates beginning in 2038. These NOL carryforwards could expire unused and be unavailable to offset future income tax liabilities if we are not able to generate sufficient taxable income to utilize our state NOL carryforwards before they expire. We have recorded a full valuation allowance related to our carryforwards due to the uncertainty of the ultimate realization of the future benefits of those assets.

Furthermore, under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, the amount of benefits from our NOL carryforwards may be impaired or limited if we incur a cumulative ownership change of more than 50% over a three-year period. The completion of this offering, and future offerings of our securities may trigger such an ownership change. In addition, because we will need to raise substantial additional funding to finance our operations, we may in the future undergo further ownership changes. We have not conducted an analysis as to whether such a change of ownership has occurred, but if such a change has occurred or occurs in the future, we will be limited regarding the amount of NOL carryforwards that can be utilized annually in the future to offset taxable income. Any such annual limitation may significantly reduce the value of our NOL carryforwards before they expire, which could result in greater tax liabilities than we would incur in the absence of such a limitation.

We may have exposure to greater-than-anticipated tax liabilities, which could seriously harm our business.

The tax laws applicable to our international business activities, including the laws of the United States and other jurisdictions, are subject to change and uncertain interpretation. The U.S. government may enact significant changes to the taxation of business entities including, among others, the imposition of additional minimum taxes and an increase in the corporate tax rate. Any such change could have a significant impact on our cash flow.

Our income tax obligations are based on our corporate operating structure and third-party and intercompany arrangements, including the manner in which we develop, value, and use our intellectual property and the valuations of our intercompany transactions. The taxing authorities of the jurisdictions in which we operate may challenge our methodologies for valuing developed technology, intercompany arrangements, or transfer pricing, which could increase our worldwide effective tax rate and the amount of taxes we pay and seriously harm our business. Taxing authorities also may determine that the manner in which we operate our business is not consistent with how we report our income, which could increase our effective tax rate and the amount of taxes we pay and seriously harm our business. In addition, our future income taxes could fluctuate because of earnings being lower than anticipated in jurisdictions that have lower statutory tax rates and higher than anticipated in jurisdictions that have higher statutory tax rates, by changes in the valuation of our deferred tax assets and liabilities. We are subject to regular review and audit by U.S. federal and state and foreign tax authorities. Any adverse outcome from a review or audit could seriously harm our business. In addition, determining our worldwide provision for income taxes and other tax liabilities requires significant judgment by management, and there are many transactions where the ultimate tax determination is uncertain. Although we believe that our estimates are reasonable, the ultimate tax outcome may differ from the amounts recorded in our financial statements for such period or periods and may seriously harm our business.

Exchange rate fluctuations may adversely affect our business, results of operations and financial condition.

We have operations, including employing a portion of our workforce, in Ottawa, Canada. Owing to the international scope of our operations, fluctuations in exchange rates between the U.S. dollar and the Canadian dollar may adversely affect our business, results of operations and financial condition. As a result, our business and the price of our common stock may be affected by fluctuations in foreign exchange rates, which may have a significant impact on our results of operations and cash flows from period to period. Currently, we do not have any exchange rate hedging arrangements in place.

Risks Related to Our Operations

We will need to grow the size of our organization, and we may experience difficulties in managing this growth, which could adversely affect our business.

As of June 30, 2023, we had 112 full-time employees. As our clinical development and future commercialization plans and strategies develop, and as we transition into operating as a public company, we may

need to hire additional managerial, clinical, regulatory, sales, marketing, financial, legal and other personnel. Future growth would impose significant added responsibilities on members of management, including:

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identifying, recruiting, integrating, maintaining and motivating additional employees;

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managing our development efforts effectively, including the clinical and FDA or comparable foreign regulatory authorities review process for our current product candidates and any future product candidates, while complying with our contractual obligations to contractors and other third parties;

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developing and managing our internal manufacturing operations effectively and in a cost-effective manner while increasing production capabilities for our product candidates to commercial levels;

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identifying and establishing additional facilities for our operations; and

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improving our operational, financial and management controls, reporting systems and procedures.

Our future financial performance and our ability to commercialize our product candidates, if approved, will depend, in part, on our ability to effectively manage any future growth. Our management may have to divert a disproportionate amount of its attention away from day-to-day activities in order to devote a substantial amount of time to managing these growth activities.

We currently rely, and for the foreseeable future will continue to rely, in substantial part on certain independent organizations, advisors and consultants to provide certain services, including contract manufacturers and companies focused on antibody development and discovery activities. The services of independent organizations, advisors and consultants may not continue to be available to us on a timely or cost-efficient basis when needed, and we may not be able to find qualified replacements. In addition, if we are unable to effectively manage our outsourced activities or if the quality, accuracy or quantity of the services provided is compromised for any reason, our clinical trials may be extended, delayed or terminated, and we may not be able to obtain, or may be substantially delayed in obtaining, regulatory approval of our product candidates or otherwise advance our business. We may not be able to manage our existing consultants or find other competent outside contractors and consultants on economically reasonable terms, or at all.

If we are not able to effectively expand our organization by hiring new employees, consultants and contractors as necessary, we may not be able to successfully implement the tasks necessary to further develop and commercialize our current or any future product candidates, if approved, and, accordingly, may not achieve our research, development and future commercialization goals, which could adversely affect our business.

If we lose key management or other scientific or medical personnel, or if we fail to recruit additional highly skilled personnel, our business, results of operations and financial condition could be adversely affected.

Our ability to compete in the highly competitive biotechnology and pharmaceutical industries depends upon our ability to attract and retain highly qualified managerial, scientific and medical personnel. We are highly dependent on our executive officers and other members of our management team, including our President and Chief Executive Officer, Sammy Farah, M.B.A., Ph.D. We do not currently maintain “key person” life insurance on the lives of our executives or any of our employees. This lack of insurance means that we may not have adequate compensation for the loss of the services of these individuals. The loss of the services of any of our executive officers or other members of our management team, including our scientific and medical personnel, and our inability to find suitable replacements in a timely manner could result in delays in product development and adversely affect our business, results of operations and financial condition.

We conduct our operations at our facility in San Diego, California. This region is headquarters to many other biopharmaceutical and biotechnology companies and many academic and research institutions.

Competition for skilled personnel in our industry is intense and may limit our ability to hire and retain highly qualified personnel on acceptable terms or at all.

To induce valuable employees to remain at our company, in addition to salary and cash incentives, we have provided stock options that vest over time. The value to employees of stock options that vest over time may be significantly affected by movements in our stock price that are beyond our control, and may at any time be insufficient to counteract more lucrative offers from other companies. Despite our efforts to retain valuable employees, members of our management, scientific and development teams may terminate their employment with us on short notice. Generally, employment agreements with our key employees provide for at-will employment, which means that such employee could leave our employment at any time, with or without notice. Our success also depends on our ability to continue to attract, retain and motivate highly skilled junior, mid-level and senior scientific and medical personnel.

Our internal information technology systems, or those of our third-party contract research organizations, contract manufacturing organizations and other contractors and consultants, may fail or suffer security breaches, loss or leakage of data and other disruptions, which could result in a material disruption of our development programs, compromise sensitive information related to our business or prevent us from accessing critical information, potentially exposing us to liability, and could adversely affect our business, results of operations and financial condition.

We are increasingly dependent upon information technology systems to operate our business. In the ordinary course of business, we collect, store and transmit confidential information (including, but not limited to, intellectual property, confidential and proprietary business information and personal information). It is critical that we do so in a secure manner to maintain the confidentiality and integrity of all such information. We also have outsourced elements of our operations to third parties, and as a result we manage a significant number of third-party contractors who have access to our confidential information.

Despite the implementation of security measures, given the size and complexity and the increasing amounts of confidential information that our information technology systems maintain, such systems and those of our third-party contract research organizations, or CROs, and contract manufacturing organizations and other contractors and consultants are potentially vulnerable to attack, breakdown, damage or interruption from service interruptions, system malfunction, natural disasters, terrorism, war and telecommunication and electrical failures, as well as security breaches from inadvertent or intentional actions by our employees, contractors, consultants, business partners and/or other third parties, or from cyberattacks by malicious third parties (including the deployment of harmful malware, ransomware, malicious code, denial-of-service attacks, social engineering and other means to affect service reliability and threaten the confidentiality, integrity and availability of information), which may compromise our information technology system infrastructure or lead to data leakage. We may face increased cybersecurity risks due to our reliance on internet technology and the number of our employees who are working remotely. Furthermore, because the techniques used to obtain unauthorized access to, or to sabotage, systems change frequently and often are not recognized until launched against a target, we may be unable to anticipate these techniques or implement adequate preventative measures. We may also experience security breaches that may remain undetected for an extended period. Even if identified, we may be unable to adequately investigate or remediate incidents or breaches due to attackers increasingly using tools and techniques that are designed to circumvent controls, to avoid detection, and to remove or obfuscate forensic evidence. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur liability and reputational damage and the further development and future commercialization of our current product candidates or any future product candidates could be delayed.

We and certain of our service providers are from time to time subject to cyberattacks and security incidents. While we do not believe that we have experienced any significant system failure, accident or security breach, our data protection efforts and our investment in information technology may not in the future prevent

significant cyber incidents in our systems and those of our third-party contract research organizations and contract manufacturing organizations and other contractors and consultants that could adversely affect our business, results of operations and financial condition. For example, if such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our programs and the development of our product candidates could be delayed. In addition, the loss of clinical trial data for any of our product candidates could result in delays in our marketing approval efforts and significantly increase our costs to recover or reproduce the data. Furthermore, significant disruptions of or security breaches in our internal information technology systems and those of our third-party contract research organizations and contract manufacturing organizations and other contractors and consultants could result in the loss, misappropriation and/or unauthorized access, use, or disclosure of, or the prevention of access to, confidential information (including trade secrets or other intellectual property, proprietary business information and personal information), which could result in financial, legal, business and reputational harm to us. For example, any such event that leads to unauthorized access, use, or disclosure of personal information, including personal information regarding our clinical trial subjects or employees, could harm our reputation directly, compel us to comply with federal and/or state breach notification laws and foreign law equivalents, subject us to mandatory corrective action, and otherwise subject us to liability under laws and regulations that protect the privacy and security of personal information, which could result in significant legal and financial exposure and reputational damages that could adversely affect our business, results of operations and financial condition. Further, we do not currently maintain cybersecurity liability insurance coverage.

Our employees, independent contractors, consultants, commercial partners and vendors may engage in misconduct or other improper activities, including noncompliance with regulatory standards and requirements, which could adversely affect our business, results of operations and financial condition.

We are exposed to the risk of employee fraud or other illegal activity by our employees, independent contractors, consultants, commercial partners and vendors. Misconduct by these parties could include intentional, reckless and/or negligent conduct that fails to (1) comply with the laws of the FDA or comparable foreign regulatory authorities, (2) provide true, complete and accurate information to the FDA or comparable foreign regulatory authorities, (3) comply with manufacturing standards we have established, (4) comply with healthcare fraud and abuse laws in the United States and similar foreign fraudulent misconduct laws, or (5) report financial information or data accurately or to disclose unauthorized activities to us. If we obtain FDA or comparable foreign regulatory authorities’ approval of any of our product candidates and begin commercializing those products in the United States or abroad, our potential exposure under such laws will increase significantly, and our costs associated with compliance with such laws are also likely to increase. These laws may impact, among other things, our current activities with principal investigators and research patients, as well as proposed and future sales, marketing and education programs. It is not always possible to identify and deter misconduct by our employees, independent contractors, consultants, commercial partners and vendors. The precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations. If any actions are instituted against us and we are not successful in defending ourselves or asserting our rights, those actions could result in any of the following: the imposition of civil, criminal and administrative penalties, damages, monetary fines, individual imprisonment, disgorgement, possible exclusion from participation in government healthcare programs, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, contractual damages, reputational harm, diminished profits and future earnings and the curtailment of our operations.

If product liability lawsuits are brought against us, we may incur substantial liabilities and may be required to limit future commercialization of our product candidates, if approved, which could adversely affect our business, results of operations and financial condition.

We face an inherent risk of product liability as a result of testing our product candidates, including our current and any of our future product candidates in clinical trials and will face an even greater risk if we

commercialize any products, if approved. For example, we may be sued if our product candidates cause or are perceived to cause injury or are found to be otherwise unsuitable during clinical trials, manufacturing, marketing or sale. Any such product liability claims could include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability or a breach of warranties. Claims also could be asserted under state consumer protection acts. Product liability claims could delay or prevent completion of our development programs. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit future commercialization of our product candidates, if approved. Even successful defense would require significant financial and management resources. Regardless of the merits or eventual outcome, liability claims may result in:

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inability to bring a product candidate to the market, if approved;

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decreased demand for our products;

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injury to our reputation;

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withdrawal of clinical trial participants and inability to continue clinical trials;

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initiation of investigations by U.S. and foreign regulators;

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costs to defend the related litigation;

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diversion of management’s time and our resources;

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substantial monetary awards or settlements to trial participants;

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product recalls, withdrawals or labeling, marketing or promotional restrictions;

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loss of revenue;

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exhaustion of any available insurance and our capital resources;

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the inability to commercialize any product candidate, if approved; and

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decline in our stock price.

Our inability to obtain sufficient product liability insurance at an acceptable cost to protect against potential product liability claims could prevent or inhibit the future commercialization, if approved, of products we develop alone or with collaborators. We need to obtain additional insurance for clinical trials as our current pre-clinical and any future pre-clinical programs enter the clinical development phase. However, we may be unable to obtain, or may obtain on unfavorable terms, clinical trial insurance in amounts adequate to cover any liabilities from any of our clinical trials. Our insurance policies also may have various deductibles and exclusions, and we may be subject to a product liability claim for which we have no coverage. We may need to pay any amounts awarded by a court or negotiated in a settlement that exceed our coverage limitations or that are not covered by our insurance, and we may not have, or be able to obtain, sufficient capital to pay such amounts. Even if our agreements with any future corporate collaborators entitle us to indemnification against losses, enforcing such indemnification provisions may cause diversion of management’s time and our resources and such indemnification may not be available or adequate should any claim arise.

If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could adversely affect our business, results of operations and financial condition.

We are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our research and development activities involve the use of biological and hazardous materials and produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials, which could cause an interruption of our future commercialization efforts, research and development efforts and business operations, environmental damage resulting in costly clean-up and liabilities under applicable laws and regulations governing the use, storage, handling and disposal of these materials and specified waste products. Although we believe that the safety procedures utilized by our third-party manufacturers for handling and disposing of these materials generally comply with the standards prescribed by these laws and regulations, this may not be the case and we may not eliminate the risk of accidental contamination or injury from these materials. In such an event, we may be held liable for any resulting damages and such liability could exceed our resources and state or federal or other applicable authorities may curtail our use of certain materials and/or interrupt our business operations. Furthermore, environmental laws and regulations are complex, change frequently and have tended to become more stringent. We cannot predict the impact of such changes or our future compliance. In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials or other work-related injuries, this insurance may not provide adequate coverage against potential liabilities. Although we have environmental liability insurance for our San Diego facility as required by the related lease agreement, we do not currently carry specific biological waste or hazardous waste insurance coverage, workers compensation or property and casualty and general liability insurance policies that include coverage for damages and fines arising from biological or hazardous waste exposure or contamination.

Our insurance policies may be inadequate and potentially expose us to unrecoverable risks.

We have limited director and officer insurance and commercial insurance policies. Any significant insurance claims would have a material adverse effect on our business, results of operations and financial condition. Insurance availability, coverage terms and pricing continue to vary with market conditions. We endeavor to obtain appropriate insurance coverage for insurable risks that we identify; however, we may fail to correctly anticipate or quantify insurable risks, we may not be able to obtain appropriate insurance coverage, and insurers may not respond as we intend to cover insurable events that may occur. We have observed rapidly changing conditions in the insurance markets relating to nearly all areas of traditional corporate insurance. Such conditions have resulted in higher premium costs, higher policy deductibles and lower coverage limits. For some risks, we may not have or maintain insurance coverage because of cost or availability.

Our operations are concentrated in one location, and we or the third parties upon whom we depend may be adversely affected by earthquakes, pandemics or other natural disasters and our business continuity and disaster recovery plans may not adequately protect us from a serious disaster.

Our current operations are predominantly located in San Diego, California. Any unplanned event, such as flood, fire, explosion, earthquake, extreme weather condition, health epidemic, including the COVID-19 pandemic, power shortage, telecommunication failure or other natural or manmade accidents or incidents that result in us being unable to fully utilize our facilities, or the manufacturing facilities of our third-party contract

manufacturers, may have a material and adverse effect on our ability to operate our business, particularly on a daily basis, and have significant negative consequences on our financial and operating conditions. Loss of access to these facilities may result in increased costs, delays in the development of our product candidates or interruption of our business operations. Earthquakes, pandemics or other natural disasters could further disrupt our operations and have a material and adverse effect on our business, results of operations and financial condition. If a natural disaster, power outage or other event occurred that prevented us from using all or a significant portion of our headquarters, that damaged critical infrastructure, such as our research facilities or the manufacturing facilities of our third-party contract manufacturers, or that otherwise disrupted operations, it may be difficult or, in certain cases, impossible, for us to continue our business for a substantial period of time. The disaster recovery and business continuity plans we have in place may prove inadequate in the event of a serious disaster or similar event. We may incur substantial expenses as a result of the limited nature of our disaster recovery and business continuity plans, which, could have a material adverse effect on our business. As part of our risk management policy, we maintain insurance coverage at levels that we believe are appropriate for our business. However, in the event of an accident or incident at these facilities, the amounts of insurance may not be sufficient to satisfy any damages and losses. If our facilities, or the manufacturing facilities of our third-party contract manufacturers, are unable to operate because of an accident or incident or for any other reason, even for a short period of time, any or all of our research and development programs may be harmed and our clinical trials may be delayed. Any business interruption may adversely affect our business, results of operations and financial condition.

Risks Related to Research and Development

The successful development of biopharmaceuticals is highly uncertain.

The successful development of biotechnology is highly uncertain and is dependent on numerous factors, many of which are beyond our control. Product candidates that appear promising in the early phases of development may fail to reach the market for several reasons including:

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preclinical study results may show the product candidate to be less effective than desired or to have harmful or problematic side effects;

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clinical trial results may show the product candidates to be less effective than expected (e.g., a clinical trial could fail to meet its primary endpoint(s)), to have unacceptable side effects or toxicities or to have effects in humans that differ from previously observed effects in lab animals;

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failure to receive the necessary regulatory approvals or a delay in receiving such approvals. Among other things, such delays may be caused by slow enrollment in clinical trials, patients withdrawing from clinical trials, length of time to achieve trial endpoints, additional time requirements for data analysis, or BLA, preparation, discussions with the FDA or comparable foreign regulatory authorities and any such request for additional preclinical or clinical data, or unexpected safety or manufacturing issues or failures;

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manufacturing costs, formulation issues, pricing or reimbursement issues, or other factors that make a product candidate uneconomical; and

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the proprietary rights of others and their competing products and technologies that may prevent or otherwise make it uneconomical for one or more of our product candidates from being commercialized, if approved.

The length of time necessary to complete clinical trials and to apply for marketing approval for a final decision by a regulatory authority varies significantly from one product candidate to the next and may be difficult to predict. Even if we are successful in getting market approval, commercial success of any approved products

also will depend in large part on the availability of coverage and adequate reimbursement from third-party payors, including government payors such as the Medicare and Medicaid programs, commercial insurers, and managed care organizations, which may be affected by existing and future healthcare reform measures designed to reduce the cost of healthcare. Third-party payors could require us to conduct additional studies, including post-marketing studies related to the cost effectiveness of a product, to qualify for reimbursement, which could be costly and divert our resources. If third-party payors were to decide to not provide coverage and adequate reimbursement levels for any of our products, if approved, market acceptance and commercial success would be reduced.

In addition, if any of our product candidates are approved for marketing, we will be subject to significant regulatory obligations regarding the submission of safety and other post-marketing information and reports and registration, and will need to continue to comply (or ensure that our third-party providers comply) with cGMPs or similar foreign requirements and good clinical practices, or GCPs, for any clinical trials that we conduct post-approval. GCPs are regulations and guidelines enforced by the FDA and comparable foreign regulatory authorities for product candidates in clinical development. Regulatory authorities enforce these GCP requirements through periodic inspections of trial sponsors, clinical investigators and trial sites. In addition, there always is the risk that we or a regulatory authority might identify previously unknown problems with a product post-approval, such as adverse events of unanticipated severity or frequency. Compliance with these requirements is costly, and any failure to comply or other issues with our product candidates following approval, if any, could adversely affect our business, results of operations and financial condition.

To obtain the requisite regulatory approvals to commercialize any product candidates, we must demonstrate through extensive preclinical studies and clinical trials that our product candidates are safe, pure and potent or effective in humans. Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain.

Differences in trial design between early-stage clinical trials and later-stage clinical trials make it difficult to extrapolate the results of earlier clinical trials to later clinical trials. Moreover, clinical data often are susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in clinical trials have nonetheless failed to obtain marketing approval of their products.

Successful completion of clinical trials is a prerequisite to submitting a BLA, to the FDA, a Marketing Authorization Application, or MAA, to the European Medicines Agency, or EMA, and similar marketing applications to comparable foreign regulatory authorities, for each product candidate and, consequently, the ultimate approval and commercial marketing of any product candidates. We do not know whether any of our clinical trials will be completed on schedule, if at all.

We may experience delays in initiating or completing clinical trials. We also may experience numerous unforeseen events during, or as a result of, any future clinical trials that we could conduct that could delay or prevent our ability to receive marketing approval or commercialize our current product candidates or any future product candidates, including:

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regulators or institutional review boards, or IRBs, or ethics committees may not authorize us or our investigators to commence or continue a clinical trial or conduct a clinical trial at a prospective trial site;

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we may experience delays in reaching, or fail to reach, agreement on acceptable terms with prospective trial sites and prospective CROs the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;

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clinical trials of any product candidates may fail to show safety, purity or potency, or produce negative or inconclusive results and we may decide, or regulators may require us, to conduct additional preclinical studies or clinical trials or we may decide to abandon product development programs;

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we may experience manufacturing failures, including in our TIL selection process, resulting in a less effective product candidate in the tumor indications we are pursuing;

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the number of subjects required for clinical trials of any product candidates may be larger than we anticipate, enrollment in these clinical trials may be slower than we anticipate or subjects may drop out of these clinical trials or fail to return for post-treatment follow-up at a higher rate than we anticipate;

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our third-party contractors may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all, or may deviate from the clinical trial protocol or drop out of the trial, which may require that we add new clinical trial sites or investigators;

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we may elect to, or regulators, or IRBs or ethics committees may require that we or our investigators, suspend, vary, or terminate clinical research or trials for various reasons, including noncompliance with regulatory requirements or a finding that the participants are being exposed to unacceptable health risks;

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the cost of clinical trials of any product candidates may be greater than we anticipate;

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the supply or quality of our product candidates or other materials necessary to conduct clinical trials of our product candidates may be insufficient or inadequate to initiate or complete a given clinical trial; for example, the process development for TILs is very complicated and requires significant logistics, and any issues with this process could delay our trials;

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our product candidates may have undesirable side effects or other unexpected characteristics, causing us or our investigators, regulators, or IRBs or ethics committees to suspend or terminate the trials, or reports from clinical testing of other therapies may raise safety or efficacy concerns about our product candidates; and

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the FDA or comparable foreign regulatory authorities may require us to submit additional data such as long-term toxicology studies, or impose other requirements before permitting us to initiate a clinical trial.

We also could encounter delays if a clinical trial is suspended or terminated by us, the IRBs or ethics committees of the institutions in which such trials are being conducted, or the FDA or comparable foreign regulatory authorities, or recommended for suspension or termination by the Data Safety Monitoring Board, or DSMB, or foreign equivalent for such trial. A suspension or termination may be imposed by the FDA or comparable foreign regulatory authorities due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a product or treatment, failure to establish or achieve clinically meaningful trial endpoints, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. Many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials also may ultimately lead to the denial of regulatory approval of our product candidates. Further, the FDA or comparable foreign regulatory authorities may disagree with our clinical trial design and our interpretation of data from clinical trials, or may change the requirements for approval even after they have reviewed and commented on the design for our clinical trials.

Our product development costs will increase if we experience delays in clinical testing or marketing approvals. We do not know whether any of our clinical trials will need to be restructured or will be completed on schedule, or at all. Significant clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our product candidates and may allow our competitors to bring products to market before we do, potentially impairing our ability to successfully commercialize our product candidates and harming our business and results of operations. Any delays in our clinical development programs may adversely affect our business, results of operations and financial condition.

In addition, the FDA’s and comparable foreign regulatory authorities’ policies with respect to clinical trials may change and additional government regulations may be enacted. For instance, the regulatory landscape related to clinical trials in the European Union, or EU, recently evolved. The EU Clinical Trials Regulation, or CTR, which was adopted in April 2014 and repeals the EU Clinical Trials Directive, became applicable on January 31, 2022. While the Clinical Trials Directive required a separate clinical trial application, or CTA, to be submitted in each EU member state, to both the competent national health authority and an independent ethics committee, the CTR introduces a centralized process and only requires the submission of a single application to all EU member states concerned. The CTR allows sponsors to make a single submission to both the competent authority and an ethics committee in each EU member state, leading to a single decision per EU member state. The assessment procedure of the CTA has been harmonized as well, including a joint assessment by all EU member states concerned, and a separate assessment by each EU member state with respect to specific requirements related to its own territory, including ethics rules. Each EU member state’s decision is communicated to the sponsor via the centralized EU portal. Once the CTA is approved, clinical study development may proceed. The CTR includes a transition period. The extent to which ongoing clinical trials will be governed by the CTR varies. For clinical trials whose CTA was made under the Clinical Trials Directive before January 31, 2022, the Clinical Trials Directive will continue to apply on a transitional basis for three years. Additionally, sponsors could submit a clinical trial application under either the Clinical Trials Directive or the CTR until January 31, 2023 and, if authorized, those will be governed by the Clinical Trials Directive until January 31, 2025. By that date, all ongoing trials will become subject to the provisions of the CTR. Compliance with the CTR requirements by us and our third-party service providers, such as CROs, may impact our developments plans and may increase our operating costs.

The regulatory framework in the United Kingdom, or UK, in relation to clinical trials is derived from existing EU legislation (as implemented into UK law, through secondary legislation). On January 17, 2022, the UK Medicines and Healthcare products Regulatory Agency, or MHRA, launched an eight-week consultation on reframing the UK legislation for clinical trials. The consultation closed on March 14, 2022. The reframe aims to streamline clinical trials approvals, enable innovation, enhance clinical trials transparency, enable greater risk proportionality, and promote patient and public involvement in clinical trials. On March 21, 2023, the MHRA published the outcome of the consultation with its responses. The MHRA may aim for a partial alignment to the CTR although there may be partial divergence from the Regulation which is intended to maintain regulatory flexibility. While opting for regulatory flexibility may facilitate conduct of clinical trials in the UK, divergence from the CTR may increase the administrative burden for clinical trials conducted at sites in both the UK and the EU. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies governing clinical trials, our development plans may be impacted.

Before we can commence clinical trials for any product candidate in our preclinical programs, we must complete extensive preclinical studies that support our planned INDs in the United States, or similar applications in other jurisdictions. Our preclinical studies may not be completed on a timely basis and have an unfavorable outcome, and the FDA and comparable foreign regulatory authorities may not accept our proposed clinical

programs, or the outcome of our preclinical studies may not ultimately support the further development of our preclinical programs. As a result, we may not be able to submit INDs or similar applications for our preclinical programs on the timelines we expect, if at all, and submission of INDs or similar applications may not result in the FDA or comparable foreign regulatory authorities allowing clinical trials to begin.

Our product candidates are based on a novel approach to the treatment of cancer, which makes it difficult to predict the time and cost of product candidate development.

We have concentrated substantially all of our recent research and development efforts on product candidates based on our Selected TIL approach, and our future success depends largely on the successful development of these approaches. Any development problems we experience in the future may cause significant delays or unanticipated costs, and such development problems may not be solved. Should we encounter development problems, including unfavorable preclinical or clinical trial results, the FDA and comparable foreign regulatory authorities may refuse to authorize us to conduct additional clinical trials, and even if they do, they may not approve our product candidates, or may require additional information, tests, or trials, which could significantly delay product development and significantly increase our research and development costs. Moreover, even if we are able to provide to the FDA or comparable foreign regulatory authorities the requested information or trials, the FDA or comparable foreign regulatory authorities may not accept them and may not approve our product candidates. We also may experience delays in developing a sustainable, reproducible and scalable manufacturing process, or developing or qualifying and validating product release assays, other testing and manufacturing methods, and our equipment and facilities in a timely manner. This may prevent us from completing our clinical trials or commercializing our product candidates on a timely or profitable basis, if at all.

In addition, the clinical trial requirements of the FDA and comparable foreign regulatory authorities and the criteria these regulators use to evaluate the safety and efficacy of a product candidate vary substantially according to the type, complexity, novelty and intended use and market of the potential products. The FDA and comparable foreign regulatory authorities have limited experience with the approval of Selected TIL immunotherapies. There are no TIL therapies that have received FDA approval to date.

Our product candidates are biologics and the process of manufacturing our product candidates is complex, highly regulated and subject to multiple risks. The manufacture of our product candidates involves complex processes, including harvesting tumor fragments from patients, isolating the T-cells from the tumor fragments, multiplying the T-cells to obtain the desired dose, and ultimately infusing the T-cells back into a patient. As a result of the complexities, the cost to manufacture biologics is generally higher than traditional small molecule chemical compounds, and the manufacturing process is less reliable and is more difficult to reproduce. Further, as a result of the complexities, we may not be able to successfully manufacture Selected TILs, which could result in any of our product candidates not being differentiated from a bulk TIL product, and as a result, any of our product candidates may not be effective in the tumor indications that we are pursuing. Moreover, our manufacturing process is susceptible to product loss or failure due to logistical issues associated with the collection of tumor fragments, or starting material, from the patient, shipping such material to the manufacturing site, shipping the final product back to the patient, and infusing the patient with the product, manufacturing issues associated with the differences in patient starting material, interruptions in the manufacturing process, contamination, equipment failure, assay failures, improper installation or operation of equipment, vendor or operator error, inconsistency in cell growth, meeting pre-specified release criteria, and variability in product characteristics. Even minor deviations from normal manufacturing processes could result in reduced production yields, product defects, and other supply disruptions. If for any reason we lose a patient’s

starting material, or later developed product at any point in the process, or if any product does not meet the applicable specifications, the manufacturing process for that patient will need to be restarted, including resection of the proper amount of tumor fragment and the resulting delay may adversely affect that patient’s outcome. If microbial, viral, environmental or other contaminations are discovered in our product candidates or in the manufacturing facilities in which our product candidates are made, such manufacturing facilities may need to be closed for an extended period of time to investigate and remedy the contamination.

Because our product candidates are manufactured specifically for each individual patient, we will be required to maintain a chain of identity with respect to the patient’s tumor as it moves from the patient to the manufacturing facility, through the manufacturing process, and back to the patient. Maintaining such a chain of identity is difficult and complex, and failure to do so could result in adverse patient outcomes, loss of product, or regulatory action including withdrawal of our products from the market. Further, as product candidates are developed through preclinical studies to late-stage clinical trials towards approval and commercialization, it is common that various aspects of the development program, such as manufacturing methods, are altered along the way to optimize processes and results. Such changes carry the risk that they will not achieve these intended objectives, and any of these changes could cause our product candidates to perform differently and affect the results of planned clinical trials or other future clinical trials or otherwise necessitate the conduct of additional studies.

As a result of these challenges, we may experience delays in our clinical development and/or commercialization plans, if approved. Furthermore, we may ultimately be unable to reduce the cost of goods for our product candidates to levels that will allow for an attractive return on investment if and when those product candidates are commercialized.

The manufacture of cell therapy products requires significant expertise and capital investment, including the development of advanced manufacturing techniques and process controls. Manufacturers of cell therapy products often encounter difficulties in production, particularly in scaling up initial production. These problems include difficulties with production costs and yields, quality control, including stability of the product candidate and quality assurance testing, shortages of qualified personnel, and compliance with strictly enforced federal, state, local and foreign regulations.

Externally, to support both TIDAL-01 and TIDAL-02, we have formed deep partnerships across a global network of contract development and manufacturing organizations, or CDMOs, that specialize in bioprocess development, testing, cGMP manufacturing, formulation and filling, packaging, controlled temperature storage, and distribution. For TIDAL-01, this includes a close partnership with the Cell Therapy Facility at Moffitt Cancer Center, responsible for cGMP manufacturing, testing, release, and distribution of Selected TIL to the clinical investigators at Moffitt under our investigator sponsored clinical trial. We have separate partnerships, fully controlled and supervised by us, for the sequencing and peptide manufacturing portions of the TIDAL-01 manufacturing process. In parallel, we have completed a technology transfer of the TIDAL-01 Selected TIL manufacturing process to a U.S.-based CDMO, Charles River Laboratories. Any problems or delays we, Moffitt or our CDMOs experience in preparing for commercial scale manufacturing of a product candidate or component may result in a delay in the FDA or comparable foreign regulatory authority approval of the product candidate or may impair our ability to manufacture commercial quantities or such quantities at an acceptable cost, which could result in the delay, prevention, or impairment of clinical development and commercialization of our product candidates, if approved, and could adversely affect our business.

Moreover, we may not succeed in maintaining our relationships with our current CDMOs or establishing relationships with additional or alternative CDMOs. Our product candidates may compete with other products and product candidates for access to manufacturing facilities. There are a limited number of manufacturers that operate under cGMP regulations and that are both capable of manufacturing for us and willing to do so. If our CDMOs should cease manufacturing for us, we would experience delays in obtaining sufficient quantities of our product candidates for

clinical trials and, if approved, commercial supply. Further, our CDMOs may breach, terminate, or not renew its agreements with us. If we were to need to find alternative manufacturing facilities it would significantly impact our ability to develop, obtain regulatory approval for or market our product candidates, if approved. The commercial terms of any new arrangement could be less favorable than our existing arrangements and the expenses relating to the transfer of necessary technology and processes could be significant.

We are ultimately responsible for the manufacture of our product candidates. A failure to comply with these requirements may result in regulatory enforcement actions against our manufacturers or us, including fines and civil and criminal penalties, which could result in imprisonment, suspension or restrictions of production, injunctions, delay or denial of product approval or supplements to approved products, clinical holds or termination of clinical trials, warning or untitled letters, regulatory authority communications warning the public about safety issues with the biologic, refusal to permit the import or export of the products, product seizure, detention, or recall, operating restrictions, suits under the civil False Claims Act, corporate integrity agreements, consent decrees, or withdrawal of product approval.

Any of these challenges could delay completion of clinical trials, require bridging clinical trials or the repetition of one or more clinical trials, increase clinical trial costs, delay approval of our product candidate, impair commercialization efforts, increase our cost of goods, and have an adverse effect on our business, results of operations and financial condition.

Cell-based therapies and biologics rely on the availability of reagents, specialized equipment, and other specialty materials, which may not be available to us on acceptable terms or at all. For some of these reagents, equipment, and materials, we rely or may rely on sole source vendors or a limited number of vendors, which could impair our ability to manufacture and supply our products.

Manufacturing our product candidates requires many reagents, which are substances used in our manufacturing processes to bring about chemical or biological reactions, and other specialty materials and equipment, some of which are manufactured or supplied by small companies with limited resources and experience to support commercial biologics production. We currently depend on a limited number of vendors for certain materials and equipment used in the manufacture of our product candidates. Some of these suppliers may not have the capacity to support clinical trials and commercial products manufactured under cGMPs by biopharmaceutical firms or may otherwise be ill-equipped to support our needs. We also do not have supply contracts with many of these suppliers and may not be able to obtain supply contracts with them on acceptable terms or at all. Accordingly, we may experience delays in receiving key materials and equipment to support clinical or commercial manufacturing.

For some of these reagents, equipment, and materials, we rely and may in the future rely on sole source vendors or a limited number of vendors. An inability to continue to source product from any of these suppliers, which could be due to a number of issues, including regulatory actions or requirements affecting the supplier, adverse financial or other strategic developments experienced by a supplier, labor disputes or shortages, unexpected demands, or quality issues, could adversely affect our ability to satisfy demand for our product candidates, which could adversely and materially affect our product sales and operating results or our ability to conduct clinical trials, either of which could significantly harm our business.

Changes in product candidate manufacturing, formulation or analytical methods may result in additional costs or delay, which could adversely affect our business, results of operations and financial condition.

As product candidates are developed through preclinical studies to later-stage clinical trials towards approval and future commercialization, it is common that various aspects of the development program, such as manufacturing methods, formulation or analytical methods, are altered throughout the development process in an effort to optimize processes and results. Any of these changes could cause our product candidates to perform differently and affect the results of planned clinical trials or other future clinical trials conducted with the altered

materials or utilizing different analytical methods. Such changes also may require additional testing, or notification to, or authorization by the FDA or a comparable foreign regulatory authority. This could delay completion of clinical trials, require the conduct of bridging clinical trials or studies, require the repetition of one or more clinical trials, increase clinical trial costs, delay approval of our product candidates and/or jeopardize our ability to commence product sales and generate revenue.

Use of our product candidates could be associated with side effects, adverse events or other properties or safety risks, which could cause us to suspend or discontinue clinical trials, abandon a product candidate, delay or preclude approval, prevent market acceptance, limit the commercial profile of an approved label or result in other significant negative consequences that could severely harm our business, results of operations and financial condition.

Before obtaining regulatory approvals for the commercial sale of any of our products, we must demonstrate through lengthy, complex and expensive preclinical studies and clinical trials that our current product candidates, including our lead product candidates, and any future product candidate are both safe, pure and potent, or effective for use in such product candidate’s target indication. Clinical testing is expensive, can take many years to complete and its outcome is inherently uncertain. Failure can occur at any time during the clinical trial process. The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. In addition, initial success in clinical trials may not be indicative of results obtained when such trials are completed. There is typically an extremely high rate of attrition from the failure of product candidates proceeding through clinical trials. Product candidates in later stages of clinical trials may fail to generate desired safety and efficacy data despite having progressed through preclinical studies and initial clinical trials. A number of companies in the biopharmaceutical and biotechnology industries have suffered significant setbacks in advanced clinical trials due to lack of efficacy or unacceptable safety issues, notwithstanding promising results in earlier trials. Most product candidates that commence clinical trials are never approved and there can be no assurance that any of our clinical trials will ultimately be successful or support further clinical development of our current product candidates or any of our future product candidates or ultimately their approval.

Results of our clinical trials could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics. Undesirable side effects caused by our product candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or comparable foreign regulatory authorities. The drug-related side effects could affect patient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims. Any of these occurrences may harm our business, results of operations and financial condition significantly.

If our product candidates are associated with undesirable side effects or have unexpected characteristics in preclinical studies or clinical trials we may need to interrupt, delay or abandon their development or limit development to more narrow uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. Treatment-related side effects could also affect patient recruitment or the ability of enrolled subjects to complete the trial, or result in potential product liability claims. Any of these occurrences may prevent us from achieving or maintaining market acceptance of the affected product candidate and may harm our business, results of operations and financial condition significantly.

Patients in our ongoing and planned clinical trials may in the future suffer significant adverse events or other side effects not observed in our preclinical studies or previous clinical trials. In addition, if our product candidates are used in combination with other therapies, our product candidates may exacerbate adverse events associated with the therapy. Patients treated with our product candidates may also be undergoing surgical, radiation or chemotherapy treatments, which can cause side effects or adverse events that are unrelated to our product candidate, but may still impact the success of our clinical trials. The inclusion of critically ill patients in

our clinical trials may result in deaths or other adverse medical events due to other therapies or medications that such patients may be using or due to the gravity of such patients’ illnesses.

If significant adverse events or other side effects are observed in any of our current or future clinical trials, we may have difficulty recruiting patients to the clinical trials, patients may drop out of our trials, or we may be required to abandon the trials or our development efforts of that product candidate altogether. We, the FDA, other comparable foreign regulatory authorities or an IRB or ethics committee may suspend clinical trials of a product candidate at any time for various reasons, including a belief that subjects in such trials are being exposed to unacceptable health risks or adverse side effects. Some potential therapeutics developed in the biotechnology industry that initially showed therapeutic promise in early-stage trials have later been found to cause side effects that prevented their further development. Even if the side effects do not preclude the product candidate from obtaining or maintaining marketing approval, undesirable side effects may inhibit market acceptance due to its tolerability versus other therapies. Any of these developments could materially harm our business, results of operations and financial condition.

Additionally, if any of our product candidates receives regulatory approval, and we or others later identify undesirable side effects caused by such product, a number of potentially significant negative consequences could result. For example, the FDA could require us to adopt a Risk Evaluation and Mitigation Strategy, or REMS, to ensure that the benefits of treatment with such product candidate outweigh the risks for each potential patient, which may include, among other things, a communication plan to health care practitioners, patient education, extensive patient monitoring or distribution systems and processes that are highly controlled, restrictive and more costly than what is typical for the industry. Other potentially significant negative consequences include that:

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we may be forced to suspend marketing of that product, or decide to remove the product from the marketplace, if approved;

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regulatory authorities may withdraw or change their approvals of that product;

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regulatory authorities may require additional warnings on the label or limit access of that product to selective specialized centers with additional safety reporting and with requirements that patients be geographically close to these centers for all or part of their treatment;

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we may be required to create a medication guide outlining the risks of the product for patients, or to conduct post-marketing studies;

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we may be required to change the way the product is administered;

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we could be subject to fines, injunctions, or the imposition of criminal or civil penalties, or be sued and held liable for harm caused to subjects or patients; and

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the product may become less competitive, and our reputation may suffer.

Any of these events could diminish the usage or otherwise limit the commercial success of our product candidates and prevent us from achieving or maintaining market acceptance of the affected product candidate, if approved by applicable regulatory authorities.

If we encounter difficulties enrolling patients in our clinical trials, our clinical development activities could be delayed or otherwise adversely affected, which could adversely affect our business, results of operations and financial condition.

We may experience difficulties in patient enrollment in our clinical trials for a variety of reasons. The timely completion of clinical trials in accordance with their protocols depends, among other things, on our ability

to enroll a sufficient number of patients who remain in the trial until its conclusion. The enrollment of patients depends on many factors, including:

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the patient eligibility and exclusion criteria defined in the protocol;

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the size of the patient population required for analysis of the trial’s primary endpoints;

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the proximity of patients to trial sites;

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the design of the trial;

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our ability to recruit clinical trial investigators with the appropriate competencies and experience;

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our ability to obtain and maintain patient consents; and

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the risk that patients enrolled in clinical trials will withdraw from the trials before completion.

In addition, our clinical trials will compete with other clinical trials for patient participation for product candidates that are in the same therapeutic areas as our product candidates, and this competition will reduce the number and types of patients available to us, because some patients who might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. For example, we will compete with various other cancer therapies, including combinations studies, and as of December 2021, there were over 4,600 combination studies of checkpoint inhibitors underway, including with monoclonal antibodies, cell therapies, cancer vaccines and other therapies. Public perception of TIL-based immunotherapies also may adversely influence willingness of subjects to participate in clinical trials. Furthermore, because the number of qualified clinical investigators is limited, we expect to conduct some of our clinical trials at the same clinical trial sites that some of our competitors use, which will reduce the number of patients who are available for our clinical trials at such sites.

Further, if we implement improvements to our manufacturing process, we may decide to slow or limit enrollment while we are implementing such improvements. While we would expect such implementation to only be temporary, any resulting enrollment delays may adversely affect our business, results of operations and financial condition.

Delays in patient enrollment may result in increased costs or may affect the timing or outcome of our future clinical trials, which could prevent completion of these trials and adversely affect our business, results of operations and financial condition.

Interim, “top-line,” and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may publicly disclose preliminary or topline data from our clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the topline or preliminary results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Topline and preliminary data also remain subject to audit and verification procedures that may result in the final data being materially different from the topline or preliminary data we previously published. As a result, topline and preliminary data should be viewed with caution until the final data are available.

From time to time, we may also disclose interim data from our clinical trials. Interim data from these trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as subject enrollment continues and more data become available. Adverse differences between interim data and top-line, preliminary, or final data could significantly harm our business prospects. Further, disclosure of interim data by us or by our competitors could result in volatility in the price of our common stock.

Further, others, including regulatory authorities, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate or product, and our company in general. In addition, the information we choose to publicly disclose regarding a particular clinical trial is based on what is typically extensive information, and you or others may not agree with what we determine is material or otherwise appropriate information to include in our disclosure. If the interim, topline, or preliminary data that we report differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for and commercialize our product candidates may be harmed, which could harm our business, results of operations or financial condition.

Due to our limited resources and access to capital, we must prioritize development of certain programs and product candidates; these decisions may prove to be wrong and may adversely affect our business, results of operations and financial condition.

Because we have limited financial and human resources, we intend to initially focus on research programs and product candidates for a limited set of indications. For example, we are initially focused on the development of our lead Selected TIL product candidate TIDAL-01 in breast cancer, colorectal cancer, uveal melanoma and both cutaneous and non-cutaneous melanomas. Because TIL therapy is a relatively new and expanding area of novel therapeutic interventions, there are many uncertainties related to development, marketing, reimbursement and the commercial potential for our product candidates. As a result, we may forego or delay pursuit of opportunities with other product candidates or for other indications that later prove to have greater commercial potential or a greater likelihood of success. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

We may for a number of reasons fail to identify viable new product candidates for clinical development from our current or future research programs. If we fail to identify additional potential product candidates, our business, results of operations and financial condition could be adversely affected.

Research programs to pursue the development of our existing and planned product candidates for additional indications and to identify new product candidates and disease targets require substantial technical, financial and human resources whether they are ultimately successful or not. Our research programs may initially show promise in identifying potential indications and/or product candidates, yet fail for a number of reasons to yield results for clinical development, including:

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the research methodology used may not be successful in identifying potential indications and/or product candidates;

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potential product candidates may, after further study, be shown to have harmful adverse effects or other characteristics that indicate they are unlikely to be effective products against the indicated disease; or

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it may take greater human and financial resources than we will possess to identify additional therapeutic opportunities for our product candidates or to develop suitable potential product

candidates through internal research programs, thereby limiting our ability to develop, diversify and expand our product portfolio.

Accordingly, we may never be able to identify additional therapeutic opportunities for our product candidates or to develop suitable potential product candidates through internal research programs, which could materially adversely affect our future growth and prospects. We may focus our efforts and resources on potential product candidates or other potential programs that ultimately prove to be unsuccessful.

We may seek orphan drug designation for our product candidates, but we may be unable to obtain such designation or to obtain or maintain the benefits associated with orphan drug designation, including market exclusivity, which may cause our product revenue, if any, to be reduced.

Regulatory authorities in some jurisdictions, including the United States and the EU, may designate drugs for relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the FDA may designate a biologic as an orphan drug if it is intended to treat a rare disease or condition, which is generally defined as a patient population of fewer than 200,000 individuals in the United States, or a patient population of 200,000 or more in the United States where there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the United States.

In the United States, orphan drug designation entitles a party to financial incentives such as tax advantages and user fee waivers. Opportunities for grant funding toward clinical trial costs may also be available for clinical trials of drugs or biologics for rare diseases, regardless of whether the biologics are designated for the orphan use. In addition, if a biologic with an orphan drug designation subsequently receives the first marketing approval for the disease or condition for which it has such designation, the product is entitled to a seven-year period of marketing exclusivity, which precludes the FDA from approving another marketing application for the same drug for the same disease or condition for that time period, except in limited circumstances. If our competitors are able to obtain orphan drug exclusivity prior to us, for products that constitute the “same drug” and treat the same diseases or conditions as our product candidates, we may not be able to have competing products approved by the applicable regulatory authority for a significant period of time.

In the EU, the European Commission, following a related opinion of the EMA Committee for Orphan Medicinal Products, may orphan drug designation for medicinal products to be developed for the diagnosis, prevention or treatment of diseases that are life-threatening or chronically debilitating, for which either no satisfactory method of diagnosis, prevention, or treatment exists, or if such method exists, the medicinal product is of significant benefit to those affected by such condition. To benefit from such designation, either the prevalence of the condition must not be more than five in 10,000 people across the EU or, if more prevalent, it must be unlikely that the marketing of the medicinal product would generate sufficient returns to justify the investment needed for its development.

If a drug with orphan designation subsequently receives the first marketing approval for the indication for which it has such designation, the drug may be entitled to a period of marketing exclusivity. This precludes the FDA or the EMA from accepting another marketing application for the same drug or, in the case of the EMA, a similar drug, for the same indication during this time period. The applicable period is seven years in the United States and ten years in the EU. The period which may be extended by six months in the United States and two years in the EU for products that have complied with the respective regulatory agency’s agreed upon pediatric investigation plan. The exclusivity period in the EU can be reduced to six years if at the end of the fifth year a drug no longer meets the criteria for orphan drug designation or if the drug is sufficiently profitable that market exclusivity is no longer justified.

We may seek orphan designation for certain of our product candidates. However, we may be unsuccessful in obtaining orphan drug designation for these and may be unable to maintain the benefits associated with orphan drug designation, even if we do obtain such designation. Even if we obtain orphan drug

designation and obtain orphan drug exclusivity for any of our product candidates, that exclusivity may not effectively protect those product candidates from competition because different products can be approved for the same disease or condition. Even after an orphan drug is granted orphan exclusivity and approved, the FDA can subsequently approve a later application for the same drug for the same disease or condition before the expiration of the seven-year exclusivity period if the FDA concludes that the later drug is clinically superior in that it is shown to be safer in a substantial portion of the target populations, more effective or makes a major contribution to patient care. Similarly, the European Commission can approve a similar drug for the same therapeutic indication during the 10-year-exclusivity if we consent thereto, if we are unable to supply sufficient quantities of the drug in the EU, or if the similar product is demonstrated to be safer, more effective or otherwise clinically superior to ours. In addition, a designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. Moreover, orphan-drug-exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if we are unable to manufacture sufficient quantities of the product to meet the needs of patients with the rare disease or condition. The exclusivity period in the EU can be reduced to six years if at the end of the fifth year a drug no longer meets the criteria for orphan drug designation or if the drug is sufficiently profitable so that market exclusivity is no longer justified. Orphan drug designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process.

We may attempt to secure approval from the FDA or comparable foreign regulatory authorities through the use of accelerated approval pathways. If we are unable to obtain such approval, we may be required to conduct additional clinical trials beyond those that we contemplate, which could increase the expense of obtaining, and delay the receipt of, necessary marketing approvals. Even if we receive accelerated approval from the FDA or comparable foreign regulatory authorities, if our confirmatory trials do not verify clinical benefit, or if we do not comply with rigorous post-marketing requirements, the FDA or comparable foreign regulatory authorities may seek to withdraw accelerated approval.

We may in the future seek an accelerated approval for our one or more of our product candidates. However, because our product candidates are in early development, there can be no assurance that the FDA would approve any form of application for expedited review for any of our product candidates. Under the accelerated approval program, the FDA may grant accelerated approval to a product candidate designed to treat a serious or life-threatening condition that provides meaningful clinical benefit over available therapies upon a determination that the product candidate has an effect on a surrogate endpoint or intermediate clinical endpoint that is reasonably likely to predict clinical benefit. The FDA considers a clinical benefit to be a positive therapeutic effect that is clinically meaningful in the context of a given disease, such as irreversible morbidity or mortality. For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. An intermediate clinical endpoint is a clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit. The accelerated approval pathway may be used in cases in which the advantage of a new drug over available therapy may not be a direct therapeutic advantage, but is a clinically important improvement from a patient and public health perspective. If granted, accelerated approval is usually contingent on the sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the product’s clinical benefit. If such post-approval studies fail to confirm the product’s clinical benefit, the FDA may withdraw its approval. Furthermore, the FDA’s accelerated approval pathways do not guarantee an accelerated review by the FDA, and even if our product candidates could be granted a designation or qualify for expedited development, it would not increase the likelihood that such product candidate will receive FDA approval.

In the EU, under the centralized procedure, the EMA’s Committee for Medicinal Products for Human Use may perform an accelerated assessment of a marketing authorization application. Applicants requesting an

accelerated assessment procedure must justify that the product candidate is expected to be of major public health interest, particularly from the point of view of therapeutic innovation.

Prior to seeking accelerated approval for any of our product candidates, we intend to seek feedback from the FDA or similar foreign regulatory authorities and will otherwise evaluate our ability to seek and receive accelerated approval. There can be no assurance that after our evaluation of the feedback and other factors we will decide to pursue or submit a BLA or similar application for accelerated approval or any other form of expedited development or review. Similarly, there can be no assurance that after subsequent FDA or similar foreign regulatory authorities’ feedback we will continue to pursue or apply for accelerated approval or any other form of expedited development or review, even if we initially decide to do so. Furthermore, if we decide to submit an application for accelerated approval or other expedited development or review for our product candidates, there can be no assurance that such submission or application will be accepted or that any expedited development or review will be granted on a timely basis, or at all. The FDA or other comparable foreign regulatory authorities could also require us to conduct further studies prior to considering our application or granting approval of any type. A failure to obtain accelerated approval or any other form of expedited development or review for our product candidate would result in a longer time period to commercialization of such product candidate, if any, could increase the cost of development of such product candidate, and could harm our competitive position in the marketplace.

The FDA and other regulatory authorities actively enforce the laws and regulations prohibiting the promotion of off-label uses.

If any of our product candidates are approved and we are found to have improperly promoted off-label uses of those products, we may become subject to significant liability. The FDA and other foreign regulatory authorities strictly regulate the promotional claims that may be made about prescription products, such as our product candidates, if approved. In particular, a product may not be promoted for uses that are not approved by the FDA or such other foreign regulatory authorities as reflected in the product’s approved labeling. If we receive marketing approval for a product candidate, physicians may nevertheless prescribe it to their patients in a manner that is inconsistent with the approved label. If we are found to have promoted such off-label uses, we may become subject to significant liability. The U.S. federal government has levied large civil and criminal fines against companies for alleged improper promotion of off-label use and has enjoined several companies from engaging in off-label promotion. The government has also required companies to enter into consent decrees or imposed permanent injunctions under which specified promotional conduct is changed or curtailed. If we cannot successfully manage the promotion of our product candidates, if approved, we could become subject to significant liability, which would materially adversely affect our business and financial condition.

Risks Related to the Biotechnology Industry

We face significant competition and if we fail to compete effectively, our business, results of operations and financial condition could be adversely affected.

The biotechnology and pharmaceutical industries are characterized by intense competition, fierce defense of intellectual property and rapidly advancing technologies. Our competitors may be able to develop other therapies or drugs that are able to achieve similar or better results than our product candidates. Our competitors include major pharmaceutical, specialty pharmaceutical and existing or emerging biotechnology companies, academic institutions, governmental agencies, and public and private research institutions. Many of our competitors have substantially greater financial, technical and other resources, such as larger research and development staff and experienced marketing and manufacturing organizations and well-established sales forces, and other biopharmaceutical companies may compete by establishing collaborative arrangements with these large companies. Smaller or early-stage companies also may prove to be significant competitors, particularly as they develop novel approaches to treating disease indications that our product candidates also are focused on treating. Established biotechnology companies may also invest heavily to accelerate discovery and development of novel

therapeutics or to in-license novel therapeutics that could make the product candidates that we develop obsolete. Mergers and acquisitions in the biotechnology industry may result in even more resources being concentrated in our competitors. Competition may increase further as a result of advances in the commercial applicability of technologies and greater availability of capital for investment in these industries. Our competitors, either alone or with collaborative partners, may succeed in developing, acquiring or licensing on an exclusive basis drug or biologic products that are more effective, safer, more easily commercialized or less costly than our product candidates or may develop proprietary technologies or secure patent protection that we may need for the development of our technologies and products. We believe the key competitive factors that will affect the development and commercial success of our product candidates are efficacy, safety, tolerability, reliability, durability, convenience of use, price and reimbursement.

We anticipate competing with other companies that are focused on treating disease indications that our product candidates also are focused on treating. A competitor may develop technologies focused on the same disease pathway as our technology or may focus on treating the targeted disease in a completely different manner. Our competitors may also seek and obtain patent rights to their technologies that are similar to ours, and such patent rights may in the future affect the direction of our product development or require us to negotiate a license to such patent rights. To the extent a new drug is developed by a competitor that is more efficacious than any product candidate developed by us, this could reduce or negate the need for our product candidate. In addition, while we believe our product candidates may be used in conjunction with existing or emerging standard of care in certain disease indications, as companies continue to improve upon existing standards of care, more efficacious drug therapies could become available, reducing or completely negating the benefit of our product candidates. Our competitors also may include companies that are or will be developing therapies for the same therapeutic areas that we are targeting within our early pipeline.

We face competition from segments of the pharmaceutical, biotechnology and other related markets that pursue the development of TIL or other cell therapies for the treatment of solid tumors. Our competitors include, among others:

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companies that are developing TIL therapies such as Iovance Biotherapeutics, Inc., Achilles Therapeutics plc, Instil Bio, Inc., KSQ Therapeutics, Inc., Lyell Immunopharma, Inc., Obsidian Therapeutics, Inc., Intima Bioscience, Inc. and others; and

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companies focused on CAR-T and TCR-T cell therapies for solid-tumors, such as Adaptimmune Therapeutics PLC, Adicet Bio, Inc., Alaunos Therapeutics, Inc., Atara Biotherapeutics, Inc., and Immatics N.V.

In addition, we are aware of other privately held biotechnology companies are evaluating neoantigen directed T cell approaches. Further, there are companies utilizing other cell-based approaches that may be competitive to our product candidates. More effective small molecules, cancer vaccines and other approaches may be developed and used as first line or second line treatments, which would reduce the opportunity for our Selected TIL therapies. Furthermore, we also face competition more broadly across the oncology market for cost-effective and reimbursable cancer treatments.

The most common methods of treating patients with cancer are surgery, radiation, and drug therapy, including chemotherapy, hormone therapy, biologic therapy, such as monoclonal and bispecific antibodies, immunotherapy, cell-based therapy and targeted therapy, or a combination of any such methods. There are a variety of available drug therapies marketed for cancer. In many cases, these drugs are administered in combination to enhance efficacy. While our Selected TIL product candidates, if any are approved, may compete with these existing drugs and other therapies, to the extent they are ultimately used in combination with or as an adjunct to these therapies, our Selected TIL product candidates may not be competitive with them.

Even if we obtain regulatory approval of our product candidates, the availability and price of our competitors’ products as well as limits on health insurance reimbursements for our product candidates could limit

the demand and the price we are able to charge for our product candidates. We may not be able to implement our business plan if the acceptance of our product candidates is inhibited by price competition or the reluctance of physicians to switch from existing methods of treatment to our product candidates, or if physicians switch to other new drug or biologic products or choose to reserve our product candidates for use in limited circumstances. We believe our ability to successfully compete will depend on our ability to rapidly develop new product candidates, manufacture product supply, successfully enroll patients in clinical trials, gain regulatory approval in target indications, establish collaborations, successfully market and commercialize, and secure and protect intellectual property rights.

The commercial success of our product candidates will depend in part on public acceptance of the use of cancer immunotherapies and TIL-based immunotherapies. Adverse events in clinical trials of our product candidates or in clinical trials of others developing similar products and the resulting publicity, as well as any other negative developments in the field of immuno-oncology and TIL-based immunotherapy that may occur in the future, could result in a decrease in demand for any product candidates that we may develop. These events also could result in the suspension, discontinuation, or clinical hold of or modification to our clinical trials. If public perception is influenced by claims that the use of cancer immunotherapies and TIL-based immunotherapies is unsafe, whether related to our therapies or those of our competitors, our product candidates may not be accepted by the general public or the medical community and potential clinical trial subjects may be discouraged from enrolling in our clinical trials. As a result, we may not be able to continue or may be delayed in conducting our development programs.

Future negative developments in the field of immuno-oncology or the biotechnology industry also could result in greater governmental regulation, stricter labeling requirements and potential regulatory delays in the testing or approvals of our products. Any increased scrutiny could delay or increase the costs of obtaining marketing approval for any of our product candidates.

Even if a product candidate we develop receives marketing approval, it may fail to achieve the degree of market acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial success and any revenue that we generate from its sales could be limited.

We have never commercialized a product candidate for any indication. If our current product candidates, including our lead product candidates, or any future product candidate we develop receives marketing approval, whether as a single agent or in combination with other therapies, it may nonetheless fail to gain sufficient market acceptance by physicians, patients, third-party payors, and others in the medical community. If the product candidates we develop do not achieve an adequate level of acceptance, we may not generate significant product revenues and we may not become profitable. The degree of market acceptance of any of our product candidates, if approved for commercial sale, will depend on a number of factors, including:

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efficacy and potential advantages compared to alternative treatments;

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the ability to offer our products, if approved, for sale at competitive prices;

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convenience and ease of administration compared to alternative treatments;

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the willingness of the target patient population to try new therapies and of physicians to prescribe these therapies;

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the strength of marketing and distribution support;

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the ability to obtain sufficient third-party payor coverage and adequate reimbursement; and

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the prevalence and severity of any side effects.

If our product candidates, if approved, do not achieve an adequate level of market acceptance, our business, results of operations and financial condition may be adversely affected.

The size of the potential commercial opportunities for our product candidates is difficult to estimate and, if any of our assumptions are inaccurate, the actual markets for our product candidates may be smaller than our estimates.

The potential commercial opportunities for our product candidates are difficult to estimate and will depend in large part on the drugs with which our product candidates are co-administered and the success of competing therapies and therapeutic approaches. In particular, the commercial opportunity for TIL-based therapies is hard to estimate given that it is an emerging field with no approved TIL therapies. Our estimates of the potential commercial opportunities are predicated on many assumptions, which may include industry knowledge and publications, third-party research reports, and other surveys. The number of patients in the United States and other major markets and elsewhere may turn out to be lower than expected, patients may not be otherwise amenable to treatment with our product candidates or new patients may become increasingly difficult to identify or gain access to, all of which would adversely affect our business, results of operations and financial condition. Although we believe that our internal assumptions are reasonable, these assumptions involve the exercise of significant judgment on the part of our management, are inherently uncertain, and their reasonableness has not been assessed by an independent source. If any of the assumptions proves to be inaccurate, the actual markets for our product candidates could be smaller than our estimates of the potential commercial opportunities, which could adversely affect our business, results of operations and financial condition.

Risks Related to Our Reliance on Third Parties

We have relied and expect to continue to rely on third parties to conduct certain aspects of our preclinical studies, to conduct our clinical trials and to conduct investigator sponsored clinical trials of our product candidates. If these third parties do not successfully carry out their contractual duties, meet expected deadlines, comply with regulatory requirements or terminate the relationship, we may not be able to obtain regulatory approval of or commercialize any potential product candidates.

We depend upon on a significant number of third parties, including independent investigators, to conduct certain aspects of our preclinical studies and our clinical trials under agreements with universities, medical institutions, CROs, strategic partners and others. Pursuant to our collaboration agreement with Moffitt, Moffitt’s TIDAL-01 IND utilizes product candidate produced by Moffitt, which will be supporting the trial with dedicated cleanroom capacity and manufacturing priority at its on-site facility for TIDAL-01 production. We also utilize CROs to manage certain aspects of our studies, which are conducted at third party clinical sites by third party investigators.

We expect to need to negotiate budgets and contracts with such third parties, which may result in delays to our development timelines and increased costs. We will rely especially heavily on third parties over the course of our clinical trials, and, as a result, will have limited control over and limited visibility into their day-to-day activities, including with respect to their compliance with the clinical protocol. Nevertheless, we are responsible for ensuring that each of our trials is conducted in accordance with the applicable protocol, legal and regulatory requirements and scientific standards, and our reliance on third parties does not relieve us of our regulatory responsibilities. We and these third parties are required to comply with GCP requirements. Upon inspection, such regulatory authorities may determine that any of our clinical trials do not comply with the GCP requirements. If we or any of these third parties fail to comply with applicable GCP requirements, the clinical data generated in our clinical trials may be deemed unreliable and the FDA or comparable foreign regulatory authorities may

require us to suspend or terminate these trials or perform additional preclinical studies or clinical trials before approving our marketing applications if at all. In addition, our clinical trials must be conducted with biologic product produced under cGMP or similar foreign requirements and may require a large number of patients, whom we may not be able to recruit.

Our failure or any failure by these third parties to comply with these regulations or to recruit a sufficient number of patients may require us to repeat clinical trials, which would delay the regulatory approval process. Moreover, our business may be implicated if any of these third parties violates federal or state fraud and abuse or false claims laws and regulations or healthcare privacy and security laws.

Any third parties conducting aspects of our preclinical studies or our current and future clinical trials will not be our employees and, except for remedies that may be available to us under our agreements with such third parties and the ability to enforce them, we cannot control whether or not they devote sufficient time and resources to our preclinical studies and clinical programs. These third parties also may have relationships with other commercial entities, including our competitors, for whom they also may be conducting clinical trials or other product development activities, which could affect their performance on our behalf. If these third parties do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced or if the quality or accuracy of the preclinical or clinical data they obtain is compromised due to the failure to adhere to our protocols or regulatory requirements or for other reasons, our development timelines, including clinical development timelines, may be extended, delayed or terminated and we may not be able to complete development of, obtain regulatory approval of or successfully commercialize our product candidates. As a result, our financial results and the commercial prospects for our product candidates would be harmed, our costs could increase and our ability to generate revenue could be delayed.

If any of our relationships with these third-party CROs or other similar organizations expires or is terminated, we may not be able to enter into arrangements with alternative CROs or other third parties or to do so on commercially reasonable terms, if at all. Switching or adding additional CROs involves additional cost and requires management time and focus. In addition, there is a sometime lengthy transition period when a new CRO begins work. As a result, delays may occur, which can materially impact our ability to meet our desired development timelines. Though we carefully manage our relationships with our CROs, there can be no assurance that we will not encounter similar challenges or delays in the future or that these delays or challenges will not adversely affect our business, results of operations and financial condition.

Furthermore, we have relied on, and in the future may rely on, separate institutions to conduct and sponsor clinical trials relating to our product candidates. We will not control the design or conduct of the investigator sponsored trials, and it is possible that the FDA or comparable foreign regulatory authorities will not view these investigator sponsored trials as providing adequate support for future clinical trials, whether controlled by us or third parties, for any one or more reasons, including elements of the design or execution of the trials or safety concerns or other trial results.

Such arrangements will provide us certain information rights with respect to the investigator sponsored trials, including access to and the ability to use and reference the data, including for our own regulatory filings, resulting from the investigator sponsored trials. However, we do not have control over the timing and reporting of the data from investigator sponsored trials, nor do we own the data from the investigator sponsored trials. If we are unable to confirm or replicate the results from the investigator sponsored trials or if negative results are obtained, we would likely be further delayed or prevented from advancing further clinical development of our product candidates. Further, if investigators or institutions breach their obligations with respect to the clinical development of our product candidates, or if the data proves to be inadequate compared to the firsthand knowledge we might have gained had the investigator sponsored trials been sponsored and conducted by us, then our ability to design and conduct any future clinical trials ourselves may be adversely affected.

Additionally, the FDA or comparable foreign regulatory authorities may disagree with the sufficiency of our right of reference to the preclinical, manufacturing, or clinical data generated by these investigator sponsored

trials, or our interpretation of preclinical, manufacturing, or clinical data from these investigator sponsored trials. If so, the FDA or comparable foreign regulatory authorities may require us to obtain and submit additional preclinical, manufacturing, or clinical data before we may initiate our planned trials and/or may not accept such additional data as adequate to initiate our planned trials.

Because we currently rely on third-party manufacturing and supply partners, our supply of research and development, preclinical and clinical development materials may become limited or interrupted or may not be of satisfactory quantity or quality.

We have relied and expect to continue to rely on third-party CDMOs to manufacture some of our preclinical product candidate supplies and to manufacture all of our clinical trial product supplies. Externally, to support TIDAL-01, we have formed deep partnerships across a global network of CDMOs that specialize in bioprocess development, testing, cGMP manufacturing, formulation and filling, packaging, controlled temperature storage, and distribution. For TIDAL-01, this includes a close partnership with the Cell Therapy Facility at Moffitt Cancer Center, responsible for cGMP manufacturing, testing, release, and distribution of Selected TIL to the clinical investigators at Moffitt under our investigator sponsored clinical trial. We have separate partnerships, fully controlled and supervised by us, for the sequencing and peptide manufacturing portions of the TIDAL-01 manufacturing process. In parallel, we have completed a technology transfer of the TIDAL-01 Selected TIL manufacturing process to a U.S.-based CDMO, Charles River Laboratories.

Our preclinical and clinical development product supplies may be limited, interrupted, or not of satisfactory quality or may not continue to be available at acceptable prices. In particular, any replacement of our manufacturers could require significant effort and expertise because there may be a limited number of qualified replacements; this could be particularly problematic where we rely on one CDMO for the manufacture of TIDAL-01.

Suppliers and manufacturers must meet applicable manufacturing requirements and undergo rigorous facility and process validation tests required by regulatory authorities in order to comply with regulatory standards, such as cGMP or similar foreign requirements outside the United States. In the event that any of our manufacturers fails to comply with such requirements or to perform its obligations to us in relation to quality, timing or otherwise, or if our supply of components or other materials becomes limited or interrupted for other reasons, we may be forced to manufacture the materials ourselves, for which we currently do not have the capabilities or resources, or enter into an agreement with another third-party, which we may not be able to do on reasonable terms, if at all. In some cases, the technical skills or technology required to manufacture our product candidates may be unique or proprietary to the original manufacturer and we may have difficulty transferring such skills or technology to another third-party and a feasible alternative may not exist. These factors would increase our reliance on such manufacturer or require us to obtain a license from such manufacturer in order to have another third-party manufacture our product candidates. If we are required to change manufacturers for any reason, we will be required to verify that the new manufacturer maintains facilities and procedures that comply with quality standards and with all applicable regulations and guidelines. The delays associated with the verification of a new manufacturer could negatively affect our ability to develop product candidates in a timely manner or within budget. Moreover, changes to the manufacturer or manufacturing process may be subject to the prior review by the FDA and comparable foreign regulatory authorities, and the FDA and comparable foreign regulatory authorities may not authorize us to utilize product candidates produced by different manufacturers or, if we obtain approval, to commercialize such product produced by different manufacturers than those identified in our marketing applications.

To the extent that we have existing, or enter into future, manufacturing arrangements with third parties, we will depend on these third parties to perform their obligations in a timely manner consistent with contractual and regulatory requirements, including those related to quality control and assurance. If we are unable to obtain or maintain third-party manufacturing for product candidates, or to do so on commercially reasonable terms, if at all, we may not be able to develop and commercialize our product candidates successfully, if approved. Also, our

or a third-party’s failure to execute on our manufacturing requirements and comply with cGMPs or similar requirements could adversely affect our business in a number of ways, including:

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an inability to initiate or continue clinical trials of product candidates under development;

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delay in submitting regulatory applications, or receiving regulatory approvals, for product candidates;

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loss of the cooperation of an existing or future collaborator;

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subjecting third-party manufacturing facilities or our manufacturing facilities to additional inspections by regulatory authorities;

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requirements to cease distribution or to recall batches of our product candidates; and

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in the event of approval to market and commercialize a product candidate, an inability to meet commercial demands for our products.

Failure to maintain cGMPs or similar requirements can result in a contractor receiving FDA or comparable foreign regulatory authorities sanctions, which can impact our ability to operate, obtain or maintain regulatory approvals, or lead to delays in any clinical development programs or future commercialization of any approved products. In addition, any delay in contracting for fill and finish services, or failure of the contract manufacturer to perform the services as needed, may delay any clinical trials, registration and launches, which could adversely affect our business, results of operations and financial condition.

Our current and future collaborations are and will be important to our business. If we are unable to enter into new collaborations, or if these or any of our current collaborations are not successful, our business, results of operations and financial condition could be adversely affected.

A part of our strategy is to strategically evaluate and, as we deem appropriate, enter into additional partnerships in the future, including potentially with major biotechnology or pharmaceutical companies. For example, we entered into a collaboration agreement with Moffitt in connection for the development of TIDAL-01 and an alliance agreement with Moffitt in order to further expand our relationship and support our existing agreements with Moffitt. We have limited capabilities for product development and do not yet have any capability for commercialization. Accordingly, we may continue to enter into collaborations with other companies in the future to provide us with important technologies and funding for our programs and technology.

Our current collaborations and any future collaborations we enter into may pose a number of risks, including the following:

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collaborators have significant discretion in determining the efforts and resources that they will apply;

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collaborators may not perform their obligations as expected;

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collaborators may not pursue development and commercialization of any product candidates that achieve regulatory approval or may elect not to continue or renew development or commercialization programs or license arrangements based on clinical trial results, changes in the collaborators’ strategic focus or available funding, or external factors, such as a strategic transaction that may divert resources or create competing priorities;

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collaborators may delay clinical trials, provide insufficient funding for a clinical trial program, stop a clinical trial or abandon a product candidate, repeat or conduct new clinical trials or require a new formulation of a product candidate for clinical testing;

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collaborators could independently develop, or develop with third parties, products that compete directly or indirectly with our products and product candidates if the collaborators believe that the competitive products are more likely to be successfully developed or can be commercialized under terms that are more economically attractive than ours;

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product candidates discovered in collaboration with us may be viewed by our collaborators as competitive with their own product candidates or products, which may cause collaborators to cease to devote resources to the commercialization of our product candidates, if approved;

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collaborators may fail to comply with applicable regulatory requirements regarding the development, manufacture, distribution or marketing of a product candidate or product;

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collaborators with marketing and distribution rights to one or more of our product candidates that achieve regulatory approval, if any, may not commit sufficient resources to the marketing and distribution of such product or products;

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disagreements with collaborators, including disagreements over proprietary rights, contract interpretation or the preferred course of development, might cause delays or terminations of the research, development or future commercialization of product candidates, if approved, might lead to additional responsibilities for us with respect to product candidates, or might result in litigation or arbitration, any of which would be time-consuming and expensive;

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collaborators may seek to amend or modify the terms of any collaboration;

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collaborators may not properly maintain or defend our intellectual property rights or may use our proprietary information in such a way as to invite litigation that could jeopardize or invalidate our intellectual property or proprietary information or expose us to potential litigation;

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collaborators may infringe the intellectual property rights of third parties, which may expose us to litigation and potential liability;

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if a collaborator of ours is involved in a business combination, the collaborator might deemphasize or terminate the development or future commercialization of any product candidate licensed to it by us; and

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collaborations may be terminated by the collaborator, and, if terminated, we could be required to raise additional capital to pursue further development or future commercialization of the applicable product candidates.

If our collaborations do not result in the successful discovery, development and future commercialization of product candidates, if approved, or if one of our collaborators terminates its agreement with us, we may not receive any future research funding or milestone or royalty payments under such collaboration. All of the risks relating to product development, regulatory approval and future commercialization described in this “Risk Factors” section and elsewhere in this prospectus also apply to the activities of our therapeutic collaborators. Additionally, if one of our collaborators terminates its agreement with us, we may find it more difficult to attract new collaborators and our perception in the business and financial communities could be adversely affected.

We face significant competition in seeking appropriate partners for our product candidates, and the negotiation process is time-consuming and complex. In order for us to successfully partner our product candidates, potential partners must view these product candidates as economically valuable in markets they determine to be attractive in light of the terms that we are seeking and other available products for licensing by other companies.

Collaborations are complex, expensive and time-consuming to negotiate and document. In addition, there have been a significant number of recent business combinations among large pharmaceutical companies that have resulted in a reduced number of potential future collaborators. Our ability to reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of factors. Additionally, our collaboration agreements may contain non-competition provisions that could limit our ability to enter into strategic collaborations with future collaborators or restrict our ability to commercialize products on our own, if approved.

If we are unable to reach agreements with suitable collaborators on a timely basis, on acceptable terms, or at all, we may have to curtail the development of a product candidate, reduce or delay its development program or one or more of our other development programs, delay its potential commercialization, if approved, or reduce the scope of any sales or marketing activities, or increase our expenditures and undertake development or future commercialization activities at our own expense. If we elect to increase our expenditures to fund development or future commercialization activities on our own, we may need to obtain additional expertise and additional capital, which may not be available to us on acceptable terms, or at all. If we fail to enter into collaborations or do not have sufficient funds or expertise to undertake the necessary development and future commercialization activities, we may not be able to further develop our product candidates, bring them to market, if approved, and generate revenue from sales of drugs or continue to develop our technology, and our business, results of operations and financial condition could be adversely affected. Even if we are successful in our efforts to establish new strategic partnerships, the terms that we agree upon may not be favorable to us, and we may not be able to maintain such strategic partnerships if, for example, development or approval of a product candidate is delayed or sales of any approved product are disappointing. Any delay in entering into new strategic partnership agreements related to our product candidates could delay the development and future commercialization of our product candidates, if approved, and reduce their competitiveness even if they reach the market.

Our reliance on third parties, such as manufacturers, may subject us to risks relating to manufacturing scale-up and may cause us to undertake substantial obligations, including financial obligations.

As we continue to grow and advance our product candidates through preclinical and clinical trials, we will need to scale our operations accordingly. For example, as we conduct clinical trials of our product candidates, we need to manufacture them in large quantities. We, or any manufacturing partners, may be unable to successfully increase the manufacturing capacity for any of our product candidates in a timely or cost-effective manner, or at all. In addition, quality issues may arise during scale-up activities. If we, or any manufacturing partners, are unable to successfully scale up the manufacture of our product candidates in sufficient quality and quantity, the development, testing, and clinical trials of that product candidate may be delayed or infeasible, and regulatory approval or commercial launch of any resulting product may be delayed or not obtained, which could adversely affect our business, results of operations and financial condition.

Risks Related to Government Regulation

The regulatory approval process for our product candidates in the United States and other jurisdictions is currently uncertain and will be lengthy, time-consuming and inherently unpredictable, and we may experience significant delays in the clinical development and regulatory approval, if any, of our product candidates.

The research, testing, manufacturing, labeling, approval, selling, import, export, marketing and distribution of drug products, including biologics like immunotherapies and, cell therapies, are subject to extensive regulation by the FDA in the United States and other regulatory authorities. We are not permitted to market any such products in the United States until we obtain approval of a BLA from the FDA or comparable marketing applications from comparable foreign regulatory authorities. We have not previously submitted a BLA to the FDA, or similar marketing application to comparable foreign authorities. A BLA and similar foreign

applications must include extensive preclinical and clinical data and supporting information to establish that the product candidate is safe, pure and potent (or effective) for each desired indication. A BLA and similar foreign application also must include significant information regarding the chemistry, manufacturing and controls for the product, and the manufacturing facilities must complete a successful pre-license inspection.

The FDA also has the authority to require a panel of experts, referred to as an Advisory Committee, to deliberate on the adequacy of the safety and efficacy data to support approval. The opinion of the Advisory Committee, although not binding, could have a significant impact on our ability to obtain approval of any product candidates that we develop based on the completed clinical trials. Similar decisions may also be taken by foreign regulatory authorities and have similar impact.

In addition, clinical trials can be delayed or terminated for a variety of reasons, including delays or failures related to:

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obtaining regulatory authorization to begin a clinical trial, if applicable;

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the availability of financial resources to begin and complete the planned trials;

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reaching agreement on acceptable terms with prospective CROs and clinical trial sites, the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;

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obtaining approval at each clinical trial site by an independent IRB or ethics committee;

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recruiting suitable patients in sufficient number to participate in a trial in a timely manner;

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having patients complete a trial or return for post-treatment follow-up;

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clinical trial sites deviating from trial protocol, not complying with GCP requirements or dropping out of a trial;

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addressing any patient safety concerns that arise during the course of a clinical trial;

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addressing any conflicts with new or existing laws or regulations;

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our ability to obtain and maintain patient consents;

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adding new clinical trial sites; or

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manufacturing qualified materials under cGMPs or similar regulations for use in clinical trials.

Patient enrollment is a significant factor in the timing of clinical trials and is affected by many factors. Further, a clinical trial may be suspended or terminated by us, the IRBs or ethics committees for the institutions in which such trials are being conducted, or the FDA or comparable foreign regulatory authorities, or recommended for suspension or termination by the DSMB for such trial, due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or comparable foreign regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a product candidate, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. If we experience termination of, or delays in the completion of, any clinical trial of our product candidates, the commercial prospects for our product candidates will be adversely affected, and our ability to generate product revenue will be delayed or terminated. In addition, any delays in completing any clinical trials will increase our costs, slow down our product development and approval process and jeopardize our ability to commence product sales and generate revenue.

We may fail to obtain regulatory approval of our product candidates.

The general approach for FDA and equivalent foreign approval of a new biologic is to obtain dispositive data from two well-controlled, Phase 3 clinical trials of the relevant biologic in the relevant patient population. Phase 3 clinical trials typically involve hundreds of patients, have significant costs and take years to complete.

Our clinical trials results may not support approval. In addition, our product candidates could fail to receive regulatory approval for many reasons, including the following:

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the FDA or comparable foreign regulatory authorities may disagree with the design or implementation of our clinical trials;

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we may be unable to demonstrate to the satisfaction of the FDA or comparable foreign regulatory authorities that our product candidates are safe and effective for any of their proposed indications;

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the results of clinical trials may not meet the level of statistical significance required by the FDA or comparable foreign regulatory authorities for approval;

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we may be unable to demonstrate that our product candidates’ clinical and other benefits outweigh their safety risks;

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the FDA or comparable foreign regulatory authorities may disagree with our interpretation of data from preclinical studies or clinical trials;

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the data collected from clinical trials of our product candidates may not be sufficient to the satisfaction of the FDA or comparable foreign regulatory authorities to support the submission of a BLA or other comparable submission in foreign jurisdictions or to obtain regulatory approval in the United States or elsewhere;

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the FDA or comparable foreign regulatory authorities may fail to approve the manufacturing processes or facilities of third-party manufacturers with which we contract for clinical and commercial supplies; and

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the approval policies or regulations of the FDA or comparable foreign regulatory authorities may significantly change in a manner rendering our clinical data insufficient for approval.

In addition, the FDA and comparable foreign regulatory authorities may change their approval policies and new regulations may be enacted, which could delay or prevent our ability to obtain approval. If any of our product candidates fail to achieve regulatory approval due to the above factors, or otherwise, any such failure would adversely affect our business, results of operations and financial condition.

Our relationships with healthcare providers and physicians and third-party payors may be subject to applicable anti-kickback, fraud and abuse and other healthcare laws and regulations, which could expose us to criminal sanctions, civil penalties, contractual damages, reputational harm and diminished profits and future earnings.

Healthcare providers, physicians and third-party payors in the United States and elsewhere play a primary role in the recommendation and prescription of pharmaceutical products. Our current and future arrangements with healthcare providers, third-party payors and customers can expose us to broadly applicable fraud and abuse and other healthcare laws and regulations, which may constrain the business or financial arrangements and relationships through which we research, and if approved, sell, market and distribute our products. In particular, the research of our product candidates, as well as the promotion, sales and marketing of

our product candidates is subject to extensive laws designed to prevent fraud, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, structuring and commission(s), certain customer incentive programs and other business arrangements generally. Activities subject to these laws also involve the improper use of information obtained in the course of patient recruitment for clinical trials. The applicable federal, state and foreign healthcare laws and regulations laws that may affect our ability to operate include, but are not limited to:

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the federal Anti-Kickback Statute, which prohibits, among other things, knowingly and willfully soliciting, receiving, offering or paying any remuneration (including any kickback, bribe, or rebate), directly or indirectly, overtly or covertly, in cash or in kind, to induce, or in return for, either the referral of an individual, or the purchase, lease, order or recommendation of any good, facility, item or service for which payment may be made, in whole or in part, under a federal healthcare program, such as the Medicare and Medicaid programs. A person or entity can be found guilty of violating the statute without actual knowledge of the statute or specific intent to violate it. The federal Anti-Kickback Statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on the one hand and prescribers, purchasers, and formulary managers on the other;

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the federal civil and criminal false claims laws, including the federal False Claims Act or FCA, which prohibit, among other things, individuals or entities from knowingly presenting, or causing to be presented, false or fraudulent claims for payment to, or approval by Medicare, Medicaid, or other federal healthcare programs, knowingly making, using or causing to be made or used a false record or statement material to a false or fraudulent claim or an obligation to pay or transmit money to the federal government, or knowingly and improperly avoiding or decreasing or concealing an obligation to pay money to the federal government. Manufacturers can be held liable under the FCA even when they do not submit claims directly to government healthcare programs if they are deemed to “cause” the submission of false or fraudulent claims. In addition, a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the FCA. The FCA also permits a private individual acting as a “whistleblower” to bring actions on behalf of the federal government alleging violations of the FCA and to share in any monetary recovery;

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the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which created additional federal criminal statutes that prohibit knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program or obtain, by means of false or fraudulent pretenses, representations, or promises, any of the money or property owned by, or under the custody or control of, any healthcare benefit program, regardless of the payor (e.g., public or private), and knowingly and willfully falsifying, concealing or covering up by any trick or device a material fact or making any materially false statements in connection with the delivery of, or payment for, healthcare benefits, items or services relating to healthcare matters. Similar to the federal Anti-Kickback Statute, a person or entity can be found guilty of violating the health care fraud statute under HIPAA without actual knowledge of the statute or specific intent to violate it;

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the federal Physician Payments Sunshine Act and its implementing regulations, which require some manufacturers of drugs, devices, biologicals and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program (with certain exceptions) to report annually to the United States Department of Health and Human Services, or HHS, information related to payments or other transfers of value made to physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), certain non-physician practitioners (such as physician assistants and nurse practitioners), and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members;

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federal consumer protection and unfair competition laws, which broadly regulate marketplace activities and activities that potentially harm consumers; and

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analogous state and foreign laws and regulations, such as state anti-kickback and false claims laws, which may apply to claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers, and may be broader in scope than their federal equivalents; state laws that require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government or otherwise restrict payments that may be made to healthcare providers; state laws that require drug manufacturers to report information related to payments and other transfers of value to physicians and other healthcare providers or marketing expenditures; and state and local laws that require the registration of pharmaceutical sales representatives.

The distribution of pharmaceutical products is subject to additional requirements and regulations, including extensive record-keeping, licensing, storage and security requirements intended to prevent the unauthorized sale of pharmaceutical products.

The scope and enforcement of each of these laws is uncertain and subject to rapid change in the current environment of healthcare reform. Federal, state and foreign enforcement bodies have recently increased their scrutiny of interactions between healthcare companies and healthcare providers, which has led to a number of investigations, prosecutions, convictions, significant fines and penalties and settlements in the healthcare industry. Ensuring business arrangements comply with applicable healthcare laws, as well as responding to possible investigations by government authorities, can be time- and resource-consuming and may divert our management’s attention from the operation of our business.

It is possible that governmental and enforcement authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law interpreting applicable fraud and abuse or other healthcare laws and regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant civil, criminal and administrative penalties, damages, fines, disgorgement, individual imprisonment, possible exclusion from participation in federal and state funded healthcare programs, contractual damages and the curtailment or restricting of our operations, as well as additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws. Any action for violation of these laws, even if successfully defended, could cause us to incur significant legal expenses and divert management’s attention from the operation of our business. Prohibitions or restrictions on sales or withdrawal of future marketed products could adversely affect our business, results of operations and financial condition.

Obtaining and maintaining regulatory approval of our product candidates in one jurisdiction does not mean that we will be successful in obtaining regulatory approval of our product candidates in other jurisdictions.

Obtaining and maintaining regulatory approval of our product candidates in one jurisdiction does not guarantee that we will be able to obtain or maintain regulatory approval in any other jurisdiction, while a failure or delay in obtaining regulatory approval in one jurisdiction may have a negative effect on the regulatory approval process in others. For example, even if the FDA grants marketing approval of a product candidate, or comparable regulatory authorities in foreign jurisdictions also must approve the manufacturing, marketing and promotion of the product candidate in those jurisdictions. Approval procedures vary among jurisdictions and can involve requirements and administrative review periods different from, and greater than, those in the United States, including additional preclinical studies or clinical trials as clinical trials conducted in one jurisdiction may not be accepted by regulatory authorities in other jurisdictions. In some jurisdictions outside the United States a product candidate must be approved for reimbursement before it can be approved for sale in that jurisdiction. In some cases, the price that we intend to charge for our products also is subject to approval.

We also may submit marketing applications in other countries. Regulatory authorities in jurisdictions outside of the United States have requirements for approval of product candidates with which we must comply

prior to marketing in those jurisdictions. Obtaining foreign regulatory approvals and compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of our products in certain countries. If we fail to comply with the regulatory requirements in international markets and/or receive applicable marketing approvals, our target market will be reduced and our ability to realize the full market potential of our product candidates will be harmed, which could adversely affect our business, results of operations and financial condition.

Even if we receive regulatory approval of any product candidates, we will be subject to ongoing regulatory obligations and continued regulatory review, which may result in significant additional expense, and we may be subject to penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our product candidates.

If any of our product candidates are approved, they will be subject to ongoing regulatory requirements for manufacturing, labeling, packaging, storage, advertising, promotion, sampling, record-keeping, conduct of post- marketing studies and submission of safety, efficacy and other post-market information, including both federal and state requirements in the United States and requirements of comparable foreign regulatory authorities. In addition, we will be subject to continued compliance with cGMPs and similar requirements outside the United States and GCP requirements for any clinical trials that we conduct post-approval.

Manufacturers and manufacturers’ facilities are required to comply with extensive FDA and comparable foreign regulatory authority requirements, including ensuring that quality control and manufacturing procedures conform to cGMPs or similar regulations. As such, we and our contract manufacturers will be subject to continual review and inspections to assess compliance with cGMPs or similar requirements and adherence to commitments made in any BLA, other marketing application, and previous responses to inspection observations. Accordingly, we and others with which we work must continue to expend time, money, and effort in all areas of regulatory compliance, including manufacturing, production and quality control.

Any regulatory approvals that we receive for our product candidates may be subject to limitations on the approved indicated uses for which the product may be marketed or to the conditions of approval, or contain requirements for potentially costly post-marketing testing, including Phase 4 (post-approval) clinical trials and surveillance to monitor the safety and efficacy of the product candidate. The FDA or comparable foreign regulatory authorities may also require a REMS program as a condition of approval of our product candidates or similar risk management measures, which could entail requirements for long-term patient follow-up, a medication guide, physician communication plans or additional elements to ensure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. In addition, if the FDA or a comparable foreign regulatory authority approves our product candidates, we will need to comply with requirements of any such programs including submissions of safety and other post-marketing information and reports and registration.

The FDA or comparable foreign regulatory authorities may impose consent decrees or withdraw approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with our product candidates, including adverse events of unanticipated severity or frequency, or with our third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information or a “black box” warning; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution restrictions or other restrictions under a REMS program. Other potential consequences include, among other things:

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restrictions on the marketing or manufacturing of our products, withdrawal of the product from the market or voluntary or mandatory product recalls;

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fines, warning letters or holds on clinical trials;

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refusal by the FDA or comparable foreign regulatory authorities to approve pending applications or supplements to approved applications filed by us or suspension or revocation of license approvals;

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product seizure or detention or refusal to permit the import or export of our product candidates; and

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injunctions or the imposition of civil or criminal penalties.

The FDA and comparable foreign regulatory authorities strictly regulate marketing, labeling, advertising, and promotion of products that are placed on the market. Products may be promoted only for the approved indications and in accordance with the provisions of the approved label. The FDA and comparable foreign regulatory authorities actively enforce the laws and regulations prohibiting the promotion of off-label uses and a company that is found to have improperly promoted off-label uses may be subject to significant civil, criminal and administrative liability. The policies of the FDA and comparable regulatory authorities may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained and our business, results of operations and financial condition could be adversely affected.

Coverage and reimbursement may be limited or unavailable in certain market segments for our product candidates, if approved, which could make it difficult for us to sell any product candidates profitably.

The success of our product candidates, if approved, depends on the availability of coverage and adequate reimbursement from third-party payors. We cannot be certain that coverage and reimbursement will be available for, or accurately estimate the potential revenue from, our product candidates or assure that coverage and reimbursement will continue to be available for any product that we may develop that receives coverage and adequate reimbursement from one or more third-party payors. Patients who are provided medical treatment for their conditions generally rely on third-party payors to reimburse all or part of the costs associated with their treatment. Accordingly, coverage and adequate reimbursement from governmental healthcare programs, such as Medicare and Medicaid, and commercial payors is critical to new product acceptance.

Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which drugs and treatments they will cover and the amount of reimbursement. Coverage and reimbursement by a third-party payor may depend upon a number of factors, including the third-party payor’s determination that use of a product is:

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a covered benefit under its health plan;

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safe, effective and medically necessary;

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appropriate for the specific patient;

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cost-effective; and

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neither experimental nor investigational.

In the United States, no uniform policy of coverage and reimbursement for products exists among third-party payors. As a result, obtaining coverage and reimbursement approval of a product from a government or other third-party payor is a time-consuming and costly process that could require us to provide to each payor supporting scientific, clinical and cost-effectiveness data for the use of our products on a payor-by-payor basis, with no assurance that coverage and adequate reimbursement will be obtained. Even if we obtain coverage for a

given product, the resulting reimbursement payment rates might not be adequate for us to achieve or sustain profitability or may require co-payments that patients find unacceptably high. Additionally, third-party payors may not cover, or provide adequate reimbursement for, long-term follow-up evaluations required following the use of product candidates. Patients are unlikely to use our product candidates unless coverage is provided and reimbursement is adequate to cover a significant portion of the cost of our product candidates. There is significant uncertainty related to third-party payor coverage and reimbursement of newly approved products. It is difficult to predict at this time what third-party payors will decide with respect to the coverage and reimbursement for our product candidates. In addition, companion diagnostic tests require coverage and reimbursement separate and apart from the coverage and reimbursement for their companion pharmaceutical or biological products. Similar challenges to obtaining coverage and reimbursement, applicable to pharmaceutical or biological products, will apply to companion diagnostics.

Moreover, increasing efforts by governmental and third-party payors in the United States and abroad to cap or reduce healthcare costs may cause such organizations to limit both coverage and the level of reimbursement for newly approved products and, as a result, they may not cover or provide adequate payment for our product candidates. There has been increasing legislative and enforcement interest in the United States with respect to specialty drug pricing practices. Specifically, there have been several recent U.S. Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to drug pricing, reduce the cost of prescription drugs under Medicare, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drugs. At the federal level, in July 2021, the Biden administration released an executive order, “Promoting Competition in the American Economy,” with multiple provisions aimed at prescription drugs. In response to President Biden’s executive order, on September 9, 2021, HHS released a Comprehensive Plan for Addressing High Drug Prices that outlines principles for drug pricing reform and sets out a variety of potential legislative policies that Congress could pursue as well as potential administrative actions HHS can take to advance these principles. At the state level, legislatures have increasingly passed legislation and implemented regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

We expect to experience pricing pressures in connection with the sale of all of our product candidates due to the trend toward managed healthcare, the increasing influence of health maintenance organizations, cost containment initiatives and additional legislative changes.

Ongoing healthcare legislative and regulatory reform measures may adversely affect our business, results of operations and financial condition.

Changes in regulations, statutes or the interpretation of existing regulations could impact our business in the future by requiring, for example: (1) changes to our manufacturing arrangements; (2) additions or modifications to product labeling; (3) the recall or discontinuation of our products; (4) post-marketing approvals or compliance programs or (5) additional record-keeping requirements. If any such changes were to be imposed, they could adversely affect our business, results of operations and financial condition.

In the United States, there have been and continue to be a number of legislative initiatives to contain healthcare costs. For example, in March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, or collectively the ACA, was passed by Congress, which substantially changes the way health care is financed by both governmental and private insurers, and significantly impacts the U.S. pharmaceutical industry. The ACA, among other things, subjected biological products to potential competition by lower-cost biosimilars, addressed a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected, increased the minimum Medicaid rebates owed by manufacturers under the

Medicaid Drug Rebate Program and extended the rebate program to individuals enrolled in Medicaid managed care organizations, established annual fees and taxes on manufacturers of certain branded prescription drugs, and created a new Medicare Part D coverage gap discount program, in which manufacturers must agree to offer 70% point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D.

Since its enactment, certain provisions the ACA have been subject to executive, judicial and congressional challenges. On June 17, 2021, the U.S. Supreme Court dismissed the most recent challenge to the ACA on procedural grounds that argued the ACA is unconstitutional in its entirety because the “individual mandate” was repealed by Congress. Thus, the ACA will remain in effect in its current form. Further, prior to the U.S. Supreme Court ruling, President Biden issued an executive order that initiated a special enrollment period from February 15, 2021 through August 15, 2021 for purposes of obtaining health insurance coverage through the ACA marketplace. The executive order also instructed certain governmental authorities to review and reconsider their existing policies and rules that limit access to healthcare, including among others, reexamining Medicaid demonstration projects and waiver programs that include work requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through Medicaid or the ACA. On August 16, 2022, President Biden signed the Inflation Reduction Act of 2022, or IRA, into law, which among other things, extends enhanced subsidies for individuals purchasing health insurance coverage in ACA marketplaces through plan year 2025. The IRA also eliminates the “donut hole” under the Medicare Part D program beginning in 2025 by significantly lowering the beneficiary maximum out-of-pocket cost and through a newly established manufacturer discount program. It is unclear how other healthcare reform measures of the Biden administration, if any, will impact our business.

Other legislative changes have been proposed and adopted in the United States since the ACA was enacted. On August 2, 2011, the Budget Control Act of 2011, among other things included aggregate reductions of Medicare payments to providers of 2% per fiscal year. These reductions went into effect on April 1, 2013, and, due to subsequent legislative amendments, will stay in effect through 2032 unless additional Congressional action is taken. On January 2, 2013, the American Taxpayer Relief Act of 2012 was signed into law, which, among other things, further reduced Medicare payments to several types of providers. Additionally, on March 11, 2021, President Biden signed the American Rescue Plan Act of 2021 into law, which eliminates the statutory Medicaid drug rebate cap, currently set at 100% of a drug’s average manufacturer price, for single source and innovator multiple source drugs, beginning January 1, 2024. Further, the IRA, among other things, (1) directs HHS to negotiate the price of certain single-source drugs and biologics covered under Medicare and (2) imposes rebates under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation. These provisions will take effect progressively starting in fiscal year 2023, although they may be subject to legal challenges. The IRA permits HHS to implement many of these provisions through guidance, as opposed to regulation, for the initial years. HHS has and will continue to issue and update guidance as these programs are implemented. It is currently unclear how the IRA will be implemented but it is likely to have a significant effect on the pharmaceutical industry. Further, in response to the Biden administration’s October 2022 executive order, on February 14, 2023, HHS released a report outlining three new models for testing by the Centers for Medicare & Medicaid Services, or CMS, Innovation Center which will be evaluated on their ability to lower the cost of drugs, promote accessibility, and improve quality of care. It is unclear whether the models will be utilized in any health reform measures in the future.

These laws, and future state and federal healthcare reform measures may be adopted in the future, any of which may result in additional reductions in Medicare and other healthcare funding and otherwise affect the prices we may obtain for any of our product candidates for which we may obtain regulatory approval or the frequency with which any such product candidate is prescribed or used.

EU drug marketing and reimbursement regulations may materially affect our ability to market and receive coverage for our products in the EU member states.

We intend to seek approval to market our product candidates in the United States and we may also seek to do so in selected foreign jurisdictions, including the EU. If we obtain approval in one or more foreign jurisdictions for our product candidates, we will be subject to rules and regulations in those jurisdictions. In some foreign countries, particularly those in the EU, the pricing of medicinal products is subject to governmental control and other market regulations which could put pressure on the pricing and usage of our product candidates. In these countries, pricing negotiations with governmental authorities can take considerable time after obtaining marketing approval of a product candidate. Some countries provide that products may be marketed only after a reimbursement decision has been taken by the relevant regulatory authority. In addition, market acceptance and sales of our product candidates will depend significantly on the availability of adequate coverage and reimbursement from third-party payors for our product candidates and may be affected by existing and future health care reform measures.

Much like the federal Anti-Kickback Statute prohibition in the United States, the provision of benefits or advantages to physicians to induce or encourage the prescription, recommendation, endorsement, purchase, supply, order or use of medicinal products is also prohibited in the EU. The provision of benefits or advantages to physicians is governed by the national anti-bribery laws of EU member states. Infringement of these laws could result in substantial fines and imprisonment.

Payments made to physicians and healthcare organization in certain EU member states must be publicly disclosed. Moreover, agreements with physicians often must be the subject of prior notification and/or approval by the physician’s employer, his or her competent professional organization and/or the regulatory authorities of the individual EU member states. These requirements are provided in the national laws, industry codes or professional codes of conduct, applicable in the EU member states. Failure to comply with these requirements could result in reputational risk, public reprimands, administrative penalties, fines or imprisonment.

In addition, in most foreign countries, including the EU, the requirements governing drug pricing and reimbursement vary widely from country to country. For example, the EU provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. Reference pricing used by various EU member states and parallel distribution, or arbitrage between low-priced and high-priced EU member states, can further reduce prices. An EU member state may approve a specific price for the medicinal product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market. In some countries, we may be required to conduct a clinical study or other studies that compare the cost-effectiveness of any of our product candidates to other available therapies in order to obtain or maintain reimbursement or pricing approval. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any of our products. Historically, products launched in the EU do not follow price structures of the United States and generally prices tend to be significantly lower. Publication of discounts by third-party payors or authorities may lead to further pressure on the prices or reimbursement levels within the country of publication and other countries. If pricing is set at unsatisfactory levels or if reimbursement of our products is unavailable or limited in scope or amount, our revenues from sales by us or our strategic partners and the potential profitability of any of our product candidates in those countries would be negatively affected.

In December 2021, Regulation No. 2021/2282 on Health Technology Assessment, or HTA, amending Directive 2011/24/EU, was adopted. This regulation which will apply from January 12, 2025 intends to boost cooperation among EU member states in assessing health technologies, including new medicinal products, and providing the basis for cooperation at the EU level for joint clinical assessments in these areas. The regulation foresees a three-year transitional period and will permit EU member states to use common HTA tools, methodologies, and procedures across the EU, working together in four main areas, including joint clinical

assessment of the innovative health technologies with the most potential impact for patients, joint scientific consultations whereby developers can seek advice from HTA authorities, identification of emerging health technologies to identify promising technologies early, and continuing voluntary cooperation in other areas. Individual EU member states will continue to be responsible for assessing non-clinical (e.g., economic, social, ethical) aspects of health technologies, and making decisions on pricing and reimbursement.

Disruptions at the FDA and other national and foreign government authorities caused by funding shortages or global health concerns, such as COVID-19, could hinder their ability to hire, retain or deploy key leadership and other personnel, or otherwise prevent new or modified products from being developed, approved or commercialized in a timely manner or at all, which could negatively impact our business.

The ability of the FDA and comparable foreign regulatory authorities to review and approve new products can be affected by a variety of factors, including government budget and funding levels, statutory, regulatory, and policy changes, the FDA’s and foreign regulatory authorities’ ability to hire and retain key personnel and accept the payment of user fees, and other events that may otherwise affect the FDA’s and comparable foreign regulatory authorities’ ability to perform routine functions. Average review times at the FDA and comparable foreign regulatory authorities have fluctuated in recent years as a result. In addition, government funding of other government authorities that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable. Disruptions at the FDA and other national and foreign authorities also may slow the time necessary for new biologics or modifications to approved biologics to be reviewed and/or approved by necessary government authorities, which would adversely affect our business. For example, over the last several years, including for 35 days beginning on December 22, 2018, the U.S. government has shut down several times and certain regulatory authorities, such as the FDA, have had to furlough critical FDA employees and stop critical activities.

Separately, in response to the COVID-19 pandemic, in March 2020, the FDA announced its intention to postpone most inspections of foreign manufacturing facilities, and on March 18, 2020, the FDA temporarily postponed routine surveillance inspections of domestic manufacturing facilities. Subsequently, in July 2020, the FDA resumed certain on-site inspections of domestic manufacturing facilities subject to a risk-based prioritization system. The FDA utilized this risk-based assessment system to assist in determining when and where it was safest to conduct prioritized domestic inspections. Additionally, on April 15, 2021, the FDA began conducting voluntary remote interactive evaluations of certain drug manufacturing facilities and clinical research sites, among other facilities in circumstances where the FDA determines that such remote evaluation would be appropriate based on mission needs and travel limitations. In May 2021, the FDA outlined a detailed plan to move toward a more consistent state of inspectional operations, and in July 2021, the FDA resumed standard inspectional operations of domestic facilities. Since that time, the FDA has continued to monitor and implement changes to its inspectional activities to ensure the safety of its employees and those of the firms it regulates as it adapts to the evolving COVID-19 pandemic.

Regulatory authorities outside the United States have adopted similar restrictions or other policy measures in response to the COVID-19 pandemic. If a prolonged government shutdown occurs, or if global health concerns continue to prevent the FDA or other regulatory authorities from conducting their regular inspections, reviews, or other regulatory activities, it could significantly impact the ability of the FDA or other regulatory authorities to timely review and process our regulatory submissions, which could have a material adverse effect on our business.

Our product candidates for which we intend to seek approval as biologic products may face competition sooner than anticipated.

The Biologics Price Competition and Innovation Act of 2009, or BPCIA, created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. Under the BPCIA, an application for a biosimilar product may not be submitted to

the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of their product.

There is a risk that any of our product candidates approved as a biological product under a BLA would not qualify for the 12-year period of exclusivity or that this exclusivity could be shortened due to congressional action or otherwise, or that the FDA will not consider our product candidates to be reference products for competing products, potentially creating the opportunity for generic competition sooner than anticipated. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of our reference products in a way that is similar to traditional generic substitution for non-biological products is not yet clear, and will depend on a number of marketplace and regulatory factors that are still developing. If competitors are able to obtain marketing approval for biosimilars referencing our candidates, if approved, our products may become subject to competition from such biosimilars, with the attendant competitive pressure and potential adverse consequences.

Actual or perceived failures to comply with applicable data protection, privacy and security laws, regulations, standards and other requirements could adversely affect our business, results of operations, and financial condition.

The global data protection landscape is rapidly evolving, and we are or may become subject to numerous state, federal and foreign laws, requirements and regulations governing the collection, use, disclosure, retention, and security of personal information, such as information that we may collect in connection with clinical trials. Implementation standards and enforcement practices are likely to remain uncertain for the foreseeable future, and we cannot yet determine the impact future laws, regulations, standards, or perception of their requirements may have on our business. Any failure or perceived failure by us to comply with federal, state or foreign laws or regulations, our internal policies and procedures or our contracts governing our processing of personal information could result in negative publicity, government investigations and enforcement actions, claims by third parties and damage to our reputation, any of which could have a material adverse effect on our business, results of operation, and financial condition.

We may become subject to or affected by new or additional data protection laws and regulations and face increased scrutiny or attention from regulatory authorities. In the United States, HIPAA as amended by the Health Information Technology for Economic and Clinical Health Act, or collectively, HIPAA, imposes, among other things, certain standards relating to the privacy, security, transmission and breach reporting of individually identifiable health information. Most healthcare providers, including research institutions from which we obtain patient health information, are subject to privacy and security regulations promulgated under HIPAA. While we do not believe that we are currently acting as a covered entity or business associate under HIPAA and thus are not directly regulated under HIPAA, we could face substantial criminal penalties if we knowingly receive individually identifiable health information from a HIPAA-covered healthcare provider or research institution that has not satisfied HIPAA’s requirements for disclosure of individually identifiable health information.

Certain states have also adopted comparable privacy and security laws and regulations. Such laws and regulations will be subject to interpretation by various courts and other governmental authorities, thus creating potentially complex compliance issues for us and our future customers and strategic partners. For example, the California Consumer Privacy Act of 2018, or CCPA, went into effect on January 1, 2020. The CCPA creates individual privacy rights for California consumers and increases the privacy and security obligations of entities handling certain personal information. The CCPA provides for civil penalties for violations, as well as a private right of action for data breaches that is expected to increase data breach litigation. Further, the California Privacy Rights Act, or CPRA, generally went into effect on January 1, 2023 and significantly amends the CCPA and

imposes additional data protection obligations on covered businesses, including additional consumer rights processes, limitations on data uses, new audit requirements for higher risk data, and opt outs for certain uses of sensitive data. It also creates a new California data protection agency authorized to issue substantive regulations and could result in increased privacy and information security enforcement. Similar laws have passed in Virginia, Colorado, Utah, Iowa and Connecticut and have been proposed in other states and at the federal level, reflecting a trend toward more stringent privacy legislation in the United States. The enactment of such laws could have potentially conflicting requirements that would make compliance challenging. In the event that we are subject to or affected by HIPAA, the CCPA, the CPRA or other domestic privacy and data protection laws, any liability from failure to comply with the requirements of these laws could adversely affect our financial condition.

We are also or may become subject to rapidly evolving data protection laws, rules and regulations in foreign jurisdictions. For example, in Europe, the EU and the UK General Data Protection Regulations (respectively, the EU GDPR and UK GDPR; together, the GDPR) each impose strict requirements for processing the personal data of individuals within the European Economic Area, or EEA, and/or the UK. Companies that must comply with the GDPR face increased compliance obligations and risk, including more robust regulatory enforcement of data protection requirements and potential fines for noncompliance of up to €20 million under the EU GDPR and £17.5 million under the UK GDPR or 4% of the annual global revenues of the noncompliant company, whichever is greater. In addition to these fines, supervisory authorities have extensive audit and inspection rights, and powers to order temporary or permanent bans on all or some processing of personal data carried out by noncompliant actors; the GDPR also confers a private right of action on data subjects and consumer associations to lodge complaints, seek judicial remedies and obtain compensation for damages resulting from violations of the GDPR. We could be subject to potentially overlapping or divergent enforcement actions for certain actual or perceived violations. Among other requirements, the GDPR regulates transfers of personal data subject to the GDPR to third countries that have not been found to provide adequate protection to such personal data, including the United States. In July 2020, the Court of Justice of the EU, or CJEU, limited how organizations could lawfully transfer personal data from the EU/EEA to the United States by invalidating the Privacy Shield for purposes of international transfers. To facilitate such transfers a new set of standard contractual clauses, or SCCs, was issued by the European Commission but these apply only to transfers of personal data outside the EEA under the EU GDPR. Organizations are now required to comply with onerous obligations to determine the additional measures that need to be implemented and maintained to supplement such safeguards to protect the transferred personal data effectively. In March 2022, the US and EU announced a new regulatory regime intended to replace the invalidated regulations; however, this new EU-US Data Privacy Framework has not been implemented beyond an executive order signed by President Biden on October 7, 2022 on Enhancing Safeguards for United States Signals Intelligence Activities. European court and regulatory decisions subsequent to the CJEU decision of July 2020 have taken a restrictive approach to international data transfers. As supervisory authorities issue further guidance on personal data export mechanisms, and/or start taking enforcement action, we could suffer additional costs, complaints and/or regulatory investigations or fines, and/or if we are otherwise unable to transfer personal data between and among countries and regions in which we operate, it could affect the manner in which we provide our services, the geographical location or segregation of our relevant systems and operations. The GDPR may impose additional responsibility and liability in relation to personal data that we process and we may be required to put in place additional mechanisms, at significant cost and diversion of management attention, to ensure compliance with the new data protection rules. This may be onerous and adversely affect our business, results of operations and financial condition.

Although we work to comply with applicable laws, regulations and standards, our contractual obligations and other legal obligations, these requirements are evolving and may be modified, interpreted and applied in an inconsistent manner from one jurisdiction to another, and may conflict with one another or other legal obligations with which we must comply. Any failure or perceived failure by us or our employees, representatives, contractors, consultants, collaborators, or other third parties to comply with such requirements or adequately address privacy and security concerns, even if unfounded, could result in additional cost and liability to us, damage our reputation, and adversely affect our business and results of operations.

Additional laws and regulations governing international operations could adversely affect our business, results of operations and financial condition.

If we further expand our operations outside of the United States, we must dedicate additional resources to comply with numerous laws and regulations in each jurisdiction in which we plan to operate. The Foreign Corrupt Practices Act, or the FCPA prohibits any U.S. individual or business from paying, offering, authorizing payment or offering of anything of value, directly or indirectly, to any foreign official, political party or candidate and other related parties for the purpose of influencing any act or decision of the foreign entity in order to assist the individual or business in obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the United States to comply with certain accounting provisions requiring the company to maintain books and records that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of internal accounting controls for international operations.

Compliance with the FCPA is expensive and difficult, particularly in countries in which corruption is a recognized problem. In addition, the FCPA presents particular challenges in the pharmaceutical industry, because, in many countries, hospitals are operated by the government, and doctors and other hospital employees are considered foreign officials. Certain payments to hospitals in connection with clinical trials and other work have been deemed to be improper payments to government officials and have led to FCPA enforcement actions.

Various laws, regulations and executive orders also restrict the use and dissemination outside of the United States, or the sharing with certain non-U.S. nationals, of information classified for national security purposes, as well as certain products and technical data relating to those products. If we expand our presence outside of the United States, it will require us to dedicate additional resources to comply with these laws, and these laws may preclude us from developing, manufacturing, or selling certain products and product candidates outside of the United States, which could limit our growth potential and increase our research and development costs.

The failure to comply with laws governing international business practices may result in substantial civil and criminal penalties and suspension or debarment from government contracting. The U.S. Securities and Exchange Commission, or the SEC, also may suspend or bar issuers from trading securities on U.S. exchanges for violations of the FCPA’s accounting provisions.

We are subject to certain U.S. and foreign anti-corruption, anti-money laundering, export control, sanctions, and other trade laws and regulations. We can face serious consequences for violations.

Among other matters, U.S. and foreign anti-corruption, anti-money laundering, export control, sanctions, and other trade laws and regulations, which are collectively referred to as Trade Laws, prohibit companies and their employees, agents, clinical research organizations, legal counsel, accountants, consultants, contractors, and other partners from authorizing, promising, offering, providing, soliciting, or receiving directly or indirectly, corrupt or improper payments or anything else of value to or from recipients in the public or private sector. Violations of Trade Laws can result in substantial criminal fines and civil penalties, imprisonment, the loss of trade privileges, debarment, tax reassessments, breach of contract and fraud litigation, reputational harm, and other consequences. We have direct or indirect interactions with officials and employees of government authorities or government-affiliated hospitals, universities, and other organizations. We also expect our non-U.S. activities to increase over time. We plan to engage third parties for clinical trials and/or to obtain necessary permits, licenses, patent registrations, and other regulatory approvals, and we can be held liable for the corrupt or other illegal activities of our personnel, agents, or partners, even if we do not explicitly authorize or have prior knowledge of such activities.

Risks Related to Our Intellectual Property

As of May 2, 2023, we own or exclusively license 14 issued U.S. patents and 96 issued foreign patents in 21 countries. We currently own or exclusively license 13 pending U.S. patent applications, 8 U.S. provisional applications, and 121 pending foreign patent applications in 26 other countries. Our commercial success will depend in large part on obtaining and maintaining patent, trademark and trade secret protection of our proprietary technologies and our product candidates, their respective components, formulations, combination therapies, methods used to manufacture them and methods of treatment, as well as successfully defending these patents against third-party challenges. Our ability to stop unauthorized third parties from making, using, selling, offering to sell or importing our product candidates is dependent upon the extent to which we have rights under valid and enforceable patents that cover these activities. If we are unable to secure and maintain patent protection for any product or technology we develop, or if the scope of the patent protection secured is not sufficiently broad, our competitors could develop and commercialize products and technology similar or identical to ours, and our ability to commercialize any product candidates we may develop may be adversely affected.

The patenting process is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications in all jurisdictions at a reasonable cost or in a timely manner. Moreover, obtaining such protection in a timely manner, or at all, may be affected by factors or events beyond our control, such as a prolonged economic downturn, or global financial or political crises, whether or not related to the ongoing COVID-19 pandemic or the ongoing political unrest between Russia and the Ukraine. In addition, we may not pursue or obtain patent protection in all relevant markets. It also is possible that we will fail to identify and file on patentable aspects of our research and development output before it is too late to obtain patent protection. Although we enter into non-disclosure and confidentiality agreements with parties who have access to patentable aspects of our research and development output, such as our employees, corporate collaborators, outside scientific collaborators, contract research organizations, contract manufacturers, consultants, advisors and other third parties, any of these parties may breach these agreements and disclose such results before a patent application is filed, thereby jeopardizing our ability to seek patent protection. If we delay in filing a patent application, and a competitor files a patent application on the same or a similar technology before we do, we may face a limited ability to secure patent rights. Or we may not be able obtain a patent on such technology at all. Even if we can patent the technology, we may be able to patent only a limited scope of the technology, and the limited scope may be inadequate to protect our product candidates, or to block competitor products or product candidates that are similar to ours. Moreover, in some circumstances, we may not have the right to control the preparation, filing and prosecution of patent applications, or to maintain the patents, covering technology that we license from or license to third parties and are reliant on our licensors or licensees.

Composition of matter patents for biological and pharmaceutical product candidates often provide a strong form of intellectual property protection for those types of products, as such patents provide protection without regard to any method of use. Method of use patents protect the use of a product for the specified method. This type of patent does not prevent a competitor from making and marketing a product that is identical to our product for an indication that is outside the scope of the patented method. Moreover, even if competitors do not actively promote their product for our targeted indications, physicians may prescribe these products “off-label.” Although off-label prescriptions may infringe or contribute to the infringement of method of use patents, the practice is common and such infringement is difficult to prevent or prosecute.

Certain of our programs may involve combination therapies. Composition of matter and method of use patents directed to combination therapies may be subject to heightened patentability standards and, therefore, may be difficult to issue worldwide.

The strength of patents in the biotechnology and pharmaceutical field involves complex legal and scientific questions and can be uncertain. The patent applications that we own or in-license may fail to result in

issued patents with claims that cover our product candidates or uses thereof in the United States or in other foreign countries. Even if the patents do successfully issue, third parties may challenge the validity, enforceability or scope thereof, which may result in such patents being narrowed, invalidated or held unenforceable. Furthermore, even if they are unchallenged, our patents and patent applications may not adequately protect our intellectual property or prevent others from designing around our claims. If the breadth or strength of protection provided by the patent applications we hold with respect to our product candidates is threatened, it could dissuade companies from collaborating with us to develop, and threaten our ability to commercialize, our product candidates. Further, if we encounter delays in our clinical trials, the period of time during which we could market our product candidates under patent protection would be reduced.

Since patent applications in the United States and most other countries are confidential for a period of time after filing, we may not have been the first to file any patent application related to our product candidates. Furthermore, for United States applications in which all claims are entitled to a priority date before March 16, 2013, an interference proceeding can be provoked by a third-party or instituted by the United States patent office, or USPTO, to determine who was the first to invent any of the subject matter covered by the patent claims of our applications.

We may not be the first to invent the inventions covered by pending patent applications and, if we are not, we may be subject to priority disputes. We may be required to disclaim part or all of the term of certain patents or all of the term of certain patent applications. There may be prior art of which we are not aware that may affect the validity or enforceability of a patent claim. There also may be prior art of which we are aware, but which we do not believe affects the validity or enforceability of a claim, which may, nonetheless, ultimately be found to affect the validity or enforceability of a claim. No assurance can be given that if challenged, our patents would be declared by a court to be valid or enforceable or that even if found valid and enforceable, a competitor’s technology or product would be found by a court to infringe our patents. We may analyze patents or patent applications of our competitors that we believe are relevant to our activities, and consider that we are free to operate in relation to our product candidates, but our competitors may achieve issued claims, including in patents we consider to be unrelated, which block our efforts or may potentially result in our product candidates or our activities infringing such claims. The possibility exists that others will develop products which have the same effect as our products on an independent basis which do not infringe our patents or other intellectual property rights, or will design around the claims of patents that we have had issued that cover our products.

Recent or future changes in patent-related case law and/or patent reform legislation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents. For example, under the enacted Leahy-Smith America Invents Act, or America Invents Act, enacted in 2013, the United States moved from a “first to invent” to a “first-to-file” system. Under a “first-to-file” system, assuming the other requirements for patentability are met, the first inventor to file a patent application generally will be entitled to a patent on the invention regardless of whether another inventor had made the invention earlier. The America Invents Act includes a number of other significant changes to U.S. patent law, including provisions that affect the way patent applications are prosecuted, redefine prior art and establish a new post-grant review system. The effects of these changes are currently unclear as the USPTO only recently developed new regulations and procedures in connection with the America Invents Act and many of the substantive changes to patent law, including the “first-to-file” provisions, became effective in March 2013. In addition, the courts have yet to address many of these provisions and the applicability of the act and new regulations on specific patents discussed herein have not been determined and would need to be reviewed. However, the America Invents Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents, all of which could have a material adverse effect on our business and financial condition.

Recent changes in European law have caused uncertainty regarding our European patent portfolios. In particular, in 2012, the European Patent Package, or EU Patent Package, regulations were passed with the goal of providing for a single pan-European Unitary Patent, and a new European Unified Patent Court, or UPC, for

litigation of European patents. The EU Patent Package was ratified in February 2023 and currently covers 17 member states. On June 1, 2023, all European patents, including those issued prior to ratification, will by default automatically fall under the jurisdiction of the UPC and allow for the possibility of obtaining pan-European injunctions, and further will be at risk of a central revocation proceeding at the UPC in participating UPC states. Under the EU Patent Package, patent holders are permitted to “opt-out” of the UPC on a patent-by-patent basis during an initial seven-year period after the EU Patent Package is ratified, with the proviso that an “opt-out” is no longer available for EP patents for which a revocation has been initiated before the UPC. Owners of European patent applications who receive notice of grant after the EU Patent Package is ratified could, for the UPC contracting states, either obtain a Unitary Patent or validate the patent nationally and file an opt-out demand. The EU Patent Package may increase the uncertainties and costs surrounding the enforcement or defense of our issued European patents and pending applications. The full impact on future European patent filing strategy and the enforcement or defense of our issued European patents in member states and/or the UPC is not known.

Intellectual property rights do not necessarily address all potential threats to our business.

The degree of future protection for our proprietary rights is uncertain because legal means afford only limited protection and may not adequately protect our rights or permit us to gain or keep our competitive advantage. For example:

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others may be able to make or use compounds or cells that are similar to the biological compositions of our product candidates but that are not covered by the claims of our patents;

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the active biological ingredients in our current product candidates will eventually become commercially available in biosimilar drug products, and no patent protection may be available with regard to formulation or method of use;

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we or our licensors, as the case may be, may fail to meet our obligations to the U.S. government in regards to any in-licensed patents and patent applications funded by U.S. government grants, leading to the loss of patent rights;

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we or our licensors, as the case may be, might not have been the first to file patent applications for the inventions we own or control;

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others may independently develop similar or alternative technologies or duplicate any of our technologies without infringing our intellectual property rights;

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it is possible that our pending patent applications will not result in issued patents;

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it is possible that there are prior public disclosures that could invalidate our or our licensors’ patents, as the case may be, or parts of our or their patents;

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it is possible that a court could find the disclosure of our owned or -in-licensed patents is not sufficient to support the scope of issued claims, thereby invalidating the claims;

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it is possible that others may circumvent our owned or in-licensed patents;

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it is possible that there are unpublished applications or patent applications maintained in secrecy that may later issue with claims covering our products or technology similar to ours;

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the laws of foreign countries may not protect our or our licensors’, as the case may be, proprietary rights to the same extent as the laws of the United States;

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there may be significant pressure on the U.S. government and international governmental bodies to limit the scope of patent protection both inside and outside the United States for disease treatments that prove successful, as a matter of public policy regarding worldwide health concerns;

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our competitors might conduct research and development activities in the United States and other foreign countries that provide a safe harbor from patent infringement claims for certain research and development activities, as well as in countries where we do not have patent rights and then use the information learned from such activities to develop competitive product candidates for sale in our major commercial markets;

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the claims of our owned or in-licensed issued patents or patent applications, if and when issued, may not cover our product candidates;

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our owned or in-licensed issued patents may not provide us with any competitive advantages, may be narrowed in scope, or be held invalid or unenforceable as a result of legal challenges by third parties;

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we may need to initiate litigation or administrative proceedings to enforce and/or defend our patent rights which will be costly whether we win or lose;

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the inventors of our owned or in-licensed patents or patent applications may become involved with competitors, develop products or processes which design around our patents, or become hostile to us or the patents or patent applications on which they are named as inventors;

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it is possible that our owned or in-licensed patents or patent applications omit individual(s) that should be listed as inventor(s) or include individual(s) that should not be listed as inventor(s), which may cause these patents or patents issuing from these patent applications to be held invalid or unenforceable;

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we have engaged in scientific collaborations in the past, and will continue to do so in the future. Such collaborators may develop adjacent or competing products to ours that are outside the scope of our patents;

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we may not develop additional proprietary technologies for which we can obtain patent protection;

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it is possible that product candidates or diagnostic tests we develop may be covered by third parties’ patents or other exclusive rights; or

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the patents of others may have an adverse effect on our business, including if others obtain patents claiming subject matter similar to or improving that covered by our patents and patent applications.

Any difficulties we encounter in defending, or resulting inability to protect, our proprietary rights and technology, may adversely affect our business, results of operations and financial condition.

We depend on intellectual property licensed from third parties and termination of any of these licenses could result in the loss of significant rights, which could adversely affect our business, results of operations and financial condition.

We are dependent on patents, know-how and proprietary technology, both our own and licensed from others. Any termination of these licenses could result in the loss of significant rights and could harm our ability to commercialize our product candidates.

Disputes also may arise between us and our licensors regarding intellectual property subject to a license agreement, including:

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the scope of rights granted under the license agreement and other interpretation-related issues;

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whether and the extent to which our technology and processes infringe on intellectual property of the licensor that is not subject to the licensing agreement;

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our right to sublicense patent and other rights to third parties under collaborative development relationships;

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the priority of invention of patented technology;

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our diligence obligations with respect to the use of the licensed technology in relation to our development and future commercialization of our product candidates, and what activities satisfy those diligence obligations; and

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the ownership of and rights to use inventions and know-how resulting from the joint or individual creation or use of intellectual property by our licensors and us and our partners.

In addition, certain of our current and future agreements with third parties may limit or delay our ability to consummate certain transactions, may impact the value of those transactions, or may limit our ability to pursue certain activities. For example, we may enter into license agreements that are not assignable or transferable, or that require the licensor’s express consent in order for an assignment or transfer to take place. If disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates.

We generally also are subject to all of the same risks with respect to protection of intellectual property that we license, as we are for intellectual property that we own, which are described in this “Risk Factors” section. If we or our licensors fail to adequately protect this intellectual property, our business, results of operations and financial condition could be adversely affected.

If we fail to comply with our obligations under our patent licenses with third parties, we could lose license rights that are important to our business, which could adversely affect our business, results of operations and financial condition.

We are a party to license agreements pursuant to which we in-license patent and patent applications, know-how, trade secrets and data rights for our product candidates. These existing licenses impose on us various diligence, milestone payment, royalty, insurance and other obligations. If we fail to comply with these obligations, our licensors may have the right to terminate the license, in which event we would not be able to develop or market the products covered by such licensed intellectual property.

Our licensors retain certain rights under their agreements with us, including the right to use the underlying technology for noncommercial academic and research use, to publish general scientific findings from research related to the technology, and to make customary scientific and scholarly disclosures of information relating to the technology. It is difficult to monitor whether our licensors limit their use of the technology to these uses, and we could incur substantial expenses to enforce our rights to our licensed technology in the event of misuse.

We may also enter into license agreements with third parties under which we are a sublicensee. If our sublicensor fails to comply with its obligations under its upstream license agreement with its licensor, the

licensor may have the right to terminate the upstream license, which may terminate our sublicense. If this were to occur, we would no longer have rights to the applicable intellectual property unless we are able to secure our own direct license with the owner of the relevant rights, which we may not be able to do on reasonable terms, or at all, which may impact our ability to continue to develop and commercialize our product candidates incorporating the relevant intellectual property.

We may have limited control over the maintenance and prosecution of these in-licensed patents and patent applications, activities or any other intellectual property that may be related to our in-licensed intellectual property. For example, such activities by these licensors may not have been or may not be conducted in compliance with applicable laws and regulations or will result in valid and enforceable patents and other intellectual property rights. Our licensors may not successfully prosecute the patent applications to which we are licensed in a manner consistent with the best interests of our business. We have limited control over the manner in which our licensors initiate an infringement proceeding against a third-party infringer of the intellectual property rights, or defend certain of the intellectual property that is licensed to us. It is possible that the licensors’ infringement proceeding or defense activities may be less vigorous than had we conducted them ourselves.

If we are unable to protect the confidentiality of our trade secrets, our business, results of operations and financial condition could be adversely affected.

In addition to patent and other intellectual property protection, we rely heavily upon know-how and trade secret protection, as well as non-disclosure agreements and invention assignment agreements with our employees, consultants and third parties, to protect our confidential and proprietary information, especially where we do not believe patent protection is appropriate or obtainable. Elements of our product candidates, including processes for their preparation and manufacture, may involve proprietary know-how, information, or technology that is not covered by patents and that may not be patentable, and thus for these aspects we may consider trade secrets and know-how to be our primary intellectual property. We may also rely on trade secret protection as temporary protection for concepts that may be included in a future patent filing. In addition to contractual measures, we try to protect the confidential nature of our proprietary information using physical and technological security measures. Such measures may not, for example, in the case of misappropriation of a trade secret by an employee or third-party with authorized access, provide adequate protection for our proprietary information. Our security measures may not prevent an employee or consultant from misappropriating our trade secrets and providing them to a competitor, and recourse we take against such misconduct may be expensive and not provide an adequate remedy to protect our interests fully. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret can be difficult, expensive, and time-consuming, and the outcome is unpredictable. In addition, trade secrets may be independently developed by others in a manner that could prevent legal recourse by us. If any of our confidential or proprietary information, such as our trade secrets, were to be disclosed or misappropriated, or if any such information was independently developed by a competitor, our competitive position could be harmed.

In addition, courts outside the United States are sometimes less willing to protect trade secrets. We may need to share our proprietary information, including trade secrets, with future business partners, collaborators, contractors and others located in countries at heightened risk of theft of trade secrets, including through direct intrusion by private parties or foreign actors, and those affiliated with or controlled by state actors. If we choose to go to court to stop a third-party from using any of our trade secrets, we may incur substantial costs. These lawsuits may consume our time and other resources even if we are successful. Although we take steps to protect our proprietary information and trade secrets, including through contractual means with our employees, consultants and current and potential business partners, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets or disclose our technology.

Thus, we may not be able to meaningfully protect our trade secrets. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors and current and

potential business partners to execute confidentiality agreements upon the commencement of employment, consulting or other applicable relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual or entity during the course of the party’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. Any disclosure, either intentional or unintentional, by our employees or third-party consultants and vendors that we engage to perform research, clinical trials or manufacturing activities, or misappropriation by third parties (such as through a cybersecurity breach) of our trade secrets or proprietary information could enable competitors to duplicate or surpass our technological achievements, thus eroding our competitive position in our market. Because we expect to rely on third parties in the development and manufacture of our product candidates, we must, at times, share trade secrets with them, which increases the possibility that a competitor will discover them or that our trade secrets will be misappropriated or disclosed. In the case of employees, the agreements provide that all inventions conceived by the individual, and which are related to our current or planned business or research and development or made during normal working hours, on our premises or using our equipment or proprietary information, are our sole and exclusive property. We also have adopted policies and conduct training that provides guidance on our expectations, and our advice for best practices, in protecting our trade secrets.

We cannot prevent other companies from licensing some of the same intellectual properties that we have licensed or from otherwise duplicating our business model and operations.

Since parties we have licenses with are developing therapies to similar technologies, they may make their methods and data available to third parties, who may want to enter into our line of business and compete against us. We currently do not have any exclusive rights to our entire product portfolio that could be used to prevent third parties from duplicating our business plan or from otherwise directly competing against us. No assurance can be given that our existing exclusive rights are or will be sufficient to prevent others from competing with us and developing substantially similar products.

Third-party claims of intellectual property infringement may prevent or delay our product discovery and development efforts.

Our commercial success depends in part on our ability to research, develop, manufacture, market and sell our current and any future product candidates and use our proprietary technologies without infringing the proprietary rights of third parties. There is a substantial amount of litigation involving patents and other intellectual property rights in the biotechnology and pharmaceutical industries, as well as administrative proceedings for challenging patents, including interference, derivation, inter partes review, post grant review, and reexamination proceedings before the USPTO or oppositions and other comparable proceedings in foreign jurisdictions. We may be exposed to, or threatened with, future litigation by third parties having patent or other intellectual property rights alleging that our product candidates and/or proprietary technologies infringe their intellectual property rights. Numerous U.S. and foreign issued patents and pending patent applications, which are owned by third parties, exist in the fields in which we are developing our product candidates. We are further aware of certain patents, and patent applications in the United States and elsewhere that contain claims that, if issued in their present form, may cover our TIL products or their methods of use or manufacture. We, along with a number of third parties in the TIL cell therapy field, have been involved in opposition proceedings in Europe with respect to some of these patents. As the biotechnology and pharmaceutical industries expand and more patents are issued, the risk increases that our product candidates may give rise to claims of infringement of the patent rights of others. Moreover, it is not always clear to industry participants, including us, which patents cover various types of drugs, products or their methods of use or manufacture. Thus, because of the large number of patents issued and patent applications filed in our fields, there may be a risk that third parties may allege they have patent rights encompassing our product candidates, technologies or methods.

If a third-party claims that we infringe its intellectual property rights, we may face a number of issues, including, but not limited to:

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infringement and other intellectual property claims which, regardless of merit, may be expensive and time-consuming to litigate and may divert our management’s attention from our core business;

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substantial damages for infringement, which we may have to pay if a court decides that the product candidate or technology at issue infringes on or violates the third-party’s rights, and, if the court finds that the infringement was willful, we could be ordered to pay treble damages and the patent owner’s attorneys’ fees;

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a court prohibiting us from developing, manufacturing, marketing or selling our product candidates, or from using our proprietary technologies, unless the third-party licenses its product rights to us, which it is not required to do;

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if a license is available from such third-party (and no such license may be available), we may have to pay substantial royalties, upfront fees and other amounts, and/or grant cross-licenses to intellectual property rights for our products; and

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redesigning our product candidates or processes so they do not infringe, which may not be possible or may require substantial monetary expenditures and time.

Some of our competitors may be able to sustain the costs of complex patent litigation more effectively than we can because they have substantially greater resources. In addition, any uncertainties resulting from the initiation and continuation of any litigation could have a material adverse effect on our ability to raise the funds necessary to continue our operations or could otherwise adversely affect our business, results of operations and financial condition.

Third parties may assert that we are employing their proprietary technology without authorization. Generally, conducting clinical trials and other development activities in the United States is protected under the Safe Harbor exemption as set forth in 35 U.S.C. § 271. If and when one of our product candidates is approved by the FDA, that certain third-party may then seek to enforce its patent by filing against us a patent infringement lawsuit. In this regard, patents issued in the United States by law enjoy a presumption of validity that can be rebutted only with evidence that is “clear and convincing,” a heightened standard of proof. There may be third-party patents of which we currently are unaware with claims to materials, formulations, methods of manufacture or methods for treatment related to the use or manufacture of our product candidates. We have conducted freedom to operate analyses with respect to only certain of our products and services and we cannot guarantee that our analyses are complete and thorough, nor can we be sure that we have identified each and every patent and pending application in the United States and abroad that is relevant or necessary to the commercialization of our products and services. Because patent applications can take many years to issue, there may be currently pending patent applications which may later result in issued patents that our product candidates may infringe.

In addition, third parties may obtain patents in the future and claim that use of our technologies infringes upon these patents. If any third-party patents were held by a court of competent jurisdiction to cover the manufacturing process of our product candidates, constructs or molecules used in or formed during the manufacturing process, or any final product itself, the holders of any such patents may be able to block our ability to commercialize the product candidate unless we obtained a license under the applicable patents, or until such patents expire or they are finally determined to be held invalid or unenforceable. Similarly, if any third-party patent were held by a court of competent jurisdiction to cover aspects of our formulations, processes for manufacture or methods of use, the holders of any such patent may be able to block our ability to develop and commercialize the product candidate unless we obtained a license or until such patent expires or is finally determined to be held invalid or unenforceable. In either case, such a license may not be available on

commercially reasonable terms or at all. If we are unable to obtain a necessary license to a third-party patent on commercially reasonable terms, or at all, our ability to commercialize our product candidates may be impaired or delayed, which could in turn significantly harm our business. Even if we obtain a license, it may be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. In addition, if the breadth or strength of protection provided by our patents and patent applications is threatened, it could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates.

In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments, and, if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. This type of litigation or proceeding could substantially increase our operating losses and reduce our resources available for development activities. We may not have sufficient financial or other resources to adequately conduct such litigation or proceedings. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their substantially greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other intellectual property related proceedings could adversely affect our business, results of operations and financial condition.

Parties making claims against us may seek and obtain injunctive or other equitable relief, which could effectively block our ability to further develop and commercialize our product candidates. In addition, if our product candidates are found to infringe the intellectual property rights of third parties, these third parties may also assert infringement claims against our licensees and other parties with whom we have business relationships, and we may be required to indemnify those parties for any damages they suffer as a result of these claims. If any of these claims succeed, we may be required to pay damages on behalf of those parties or may be required to obtain licenses for the products they use. Defense of these claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of employee resources from our business. In the event of a successful claim of infringement against us, we may have to pay substantial damages, including treble damages and attorneys’ fees for willful infringement, obtain one or more licenses from third parties, pay royalties or redesign our infringing products, which may be impossible or require substantial time and monetary expenditure. Any such license may not be available at all or may not be available on commercially reasonable terms. Furthermore, even in the absence of litigation, we may need to obtain licenses from third parties to advance our research or allow future commercialization of our product candidates, if approved. We may fail to obtain any of these licenses at a reasonable cost or on reasonable terms, if at all. In that event, we would be unable to further develop and commercialize our product candidates, which could adversely affect our business, results of operations and financial condition.

Third parties may assert that our employees, consultants or other third parties have wrongfully used, disclosed confidential information, misappropriated trade secrets or are in breach of non-competition or non-solicitation agreements.

As is common in the biotechnology and pharmaceutical industries, we employ individuals who were previously employed at universities or other biopharmaceutical or pharmaceutical companies, including our competitors or potential competitors. Although no material claims against us currently are pending or threatened, and although we try to ensure that our employees, consultants and other third parties do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or our employees, consultants, independent contractors or current or potential business partners have inadvertently or otherwise used or disclosed intellectual property, including trade secrets or other proprietary information, of a former employer or other third parties, or are in breach of any non-competition or non-solicitation agreements. Litigation may be necessary to defend against these claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in defending against such claims, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses, and could distract our technical and management personnel from their normal responsibilities.

We may be subject to claims that former employees, collaborators, or other third parties have an interest in our patents or other intellectual property as an inventor or co-inventor. The failure to name the proper inventors on a patent application can result in the patents issuing thereon being unenforceable. Inventorship disputes may arise from conflicting views regarding the contributions of different individuals named as inventors, the effects of foreign laws where foreign nationals are involved in the development of the subject matter of the patent, conflicting obligations of third parties involved in developing our product candidates or as a result of questions regarding co-ownership of potential joint inventions. For example, we may have inventorship disputes arise from conflicting obligations of consultants or others who are involved in developing our product candidates. Litigation may be necessary to defend against these and other claims challenging inventorship. Alternatively, or additionally, we may enter into agreements to clarify the scope of our rights in such intellectual property. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights, such as exclusive ownership of, or right to use, valuable intellectual property.

In addition, while it is our policy to require our employees and contractors who may be involved in the conception or development of intellectual property to execute agreements assigning such intellectual property to us, we may be unsuccessful in executing such an agreement with each party who, in fact, conceives or develops intellectual property that we regard as our own. The assignment of intellectual property rights may not be self-executing, or the assignment agreements may be breached, and we may be forced to bring claims against third parties, or defend claims that they may bring against us, to determine the ownership of what we regard as our intellectual property. Such claims could have a material adverse effect on our business, results of operations and financial condition.

We may not be successful in obtaining or maintaining necessary rights to develop current and any future product candidates on acceptable terms.

Because our programs may involve additional product candidates that may require the use of proprietary rights held by third parties, the growth of our business may depend in part on our ability to acquire, in-license or use these proprietary rights.

Our product candidates also may require specific formulations to work effectively and efficiently and these rights may be held by others. We may be unable to acquire or in-license any compositions, methods of use, processes or other third-party intellectual property rights from third parties that we identify as necessary or important to our business operations. We may fail to obtain any of these licenses at a reasonable cost or on reasonable terms, if at all, which would harm our business. We may need to cease use of the compositions or methods covered by such third-party intellectual property rights, and may need to seek to develop alternative approaches that do not infringe on such intellectual property rights which may entail additional costs and expenses and development delays, even if we were able to develop such alternatives, which may not be feasible. Even if we are able to obtain a license, it may be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. In that event, we may be required to expend significant time and resources to develop or license replacement technology.

Additionally, we sometimes collaborate with academic institutions and governmental authorities to accelerate our preclinical research or development under written agreements with these institutions. In certain

cases, these institutions provide us with an option to negotiate a license to any of the institution’s rights in technology resulting from the collaboration. Regardless of such option, we may be unable to negotiate a license within the specified timeframe or under terms that are acceptable to us. If we are unable to do so, the institution may offer the intellectual property rights to others, potentially blocking our ability to pursue our program. If we are unable to successfully obtain rights to required third-party intellectual property or to maintain the existing intellectual property rights we have, we may have to abandon development of such program and our business, results of operations and financial condition could be adversely affected.

The licensing and acquisition of third-party intellectual property rights is a highly competitive area, and companies, which may be more established, or have greater resources than we do, also may be pursuing strategies to license or acquire third-party intellectual property rights that we consider necessary or attractive in order to commercialize our product candidates. More established companies may have a competitive advantage over us due to their size, cash resources and greater clinical development and commercialization capabilities. There can be no assurance that we will be able to successfully complete such negotiations and ultimately acquire the rights to the intellectual property surrounding the additional product candidates that we may seek to acquire.

We may be involved in lawsuits to protect or enforce our patents or the patents of our licensors, which could be expensive, time-consuming and unsuccessful.

Competitors may infringe our patents or the patents of our licensors. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time-consuming. In patent litigation in the United States, defendant counterclaims alleging invalidity and/or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, including lack of novelty, obviousness, non-enablement or insufficient written description. Grounds for an unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld relevant information from the USPTO or made a misleading statement during prosecution. For the patents and patent applications that we have licensed, we may have limited or no right to participate in the defense of any licensed patents against challenge by a third party. If a defendant were to prevail on a legal assertion of invalidity or unenforceability, we would lose at least part, and perhaps all, of any future patent protection on our current or future product candidates. Such a loss of patent protection could harm our business.

In addition, in an infringement proceeding, a court may decide that one or more of our patents is not valid or is unenforceable, or may refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question. An adverse result in any litigation or defense proceedings could put one or more of our patents at risk of being invalidated, held unenforceable, or interpreted narrowly and could put our patent applications at risk of not issuing. Defense of these claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of employee resources from our business. Moreover, our ability to successfully pursue infringement claims or otherwise enforce intellectual property that we license from or co-own with another party may require the participation and co-operation of the co-owner or licensor, and may be impaired or prohibited if such participation or co-operation is insufficient or cannot be secured.

We may choose to challenge the patentability of claims in a third-party’s U.S. patent by requesting that the USPTO review the patent claims in an ex-parte re-exam, inter partes review or post-grant review proceedings. These proceedings are expensive and may consume our time or other resources. We may choose to challenge a third-party’s patent in patent opposition proceedings in the European Patent Office, or EPO, or another foreign patent office. The costs of these opposition proceedings could be substantial, and may consume our time or other resources. If we fail to obtain a favorable result at the USPTO, EPO or other patent office then we may be exposed to litigation by a third-party alleging that the patent may be infringed by our product candidates or proprietary technologies.

In addition, because some patent applications in the United States may be maintained in secrecy until the patents are issued, patent applications in the United States and many foreign jurisdictions are typically not

published until 18 months after filing, and publications in the scientific literature often lag behind actual discoveries, others may have filed patent applications for technology covered by our owned and in-licensed issued patents or our pending applications, and we or, if applicable, a licensor may not have been the first to invent the technology. Our competitors may have filed, and may in the future file, patent applications covering our products or technology similar to ours. Any such patent application may have priority over our owned and in-licensed patent applications or patents, which could require us to obtain rights to issued patents covering such technologies. For applications that have claims entitled to a priority date before March 16, 2013, if another party has filed a U.S. patent application on inventions similar to those owned by or in-licensed to us, we or, in the case of in-licensed technology, the licensor may have to participate in an interference proceeding declared by the USPTO to determine priority of invention in the United States. If we or one of our licensors is a party to an interference proceeding involving a U.S. patent application on inventions owned by or in-licensed to us, we may incur substantial costs, divert management’s time and expend other resources, even if we are successful.

Interference proceedings provoked by third parties or brought by the USPTO may be necessary to determine the priority of inventions with respect to our patents or patent applications or those of our licensors. An unfavorable outcome could result in a loss of our current patent rights and could require us to cease using the related technology or to attempt to license rights to it from the prevailing party. Our business could be harmed if the prevailing party does not offer us a license on commercially reasonable terms. Litigation or interference proceedings may result in a decision adverse to our interests and, even if we are successful, may result in substantial costs and distract our management and other employees. We may not be able to prevent, alone or with our licensors, misappropriation of our trade secrets or confidential information, particularly in countries where the laws may not protect those rights as fully as in the United States.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock.

Obtaining and maintaining our patent protection depends on compliance with various procedural, document submission, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

Periodic maintenance fees, renewal fees, annuity fees, and various other governmental fees on any issued patent are due to be paid to the USPTO and foreign patent agencies in several stages over the lifetime of the patent. The USPTO and various foreign governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other provisions during the patent application process and following the issuance of a patent. While an inadvertent lapse can in many cases be cured by payment of a late fee or by other means in accordance with the applicable rules, there are situations in which noncompliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. Noncompliance events that could result in abandonment or lapse of a patent or patent application include, but are not limited to, failure to respond to official actions within prescribed time limits, non-payment of fees and failure to properly legalize and submit formal documents. In such an event, our competitors might be able to enter the market, which could adversely affect our business, results of operations and financial condition.

Issued patents covering our product candidates could be found invalid or unenforceable if challenged in court or the USPTO.

If we or one of our licensing partners initiate legal proceedings against a third-party to enforce a patent covering one of our product candidates, the defendant could counterclaim that the patent covering our product candidate, as applicable, is invalid and/or unenforceable. In patent litigation in the United States, defendant

counterclaims alleging invalidity and/or unenforceability are commonplace, and there are numerous grounds upon which a third-party can assert invalidity or unenforceability of a patent. Third parties also may raise similar claims before administrative bodies in the United States or abroad, even outside the context of litigation. Such mechanisms include re-examination, inter partes review, post grant review, derivation proceedings and equivalent proceedings in foreign jurisdictions (e.g., opposition proceedings). Such proceedings could result in revocation or amendment to our patents in such a way that they no longer cover our product candidates. The outcome following legal assertions of invalidity and unenforceability is unpredictable. With respect to the validity question, for example, there may be invalidating prior art, of which we, our patent counsel and the patent examiner were unaware during prosecution. If a defendant were to prevail on a legal assertion of invalidity and/or unenforceability, or if we are otherwise unable to adequately protect our rights, we would lose at least part, and perhaps all, of the patent protection on our product candidates. Such a loss of patent protection could adversely affect our business, results of operations and financial condition.

Changes in patent law in the United States and in other jurisdictions could diminish the value of patents in general, thereby impairing our ability to protect our products.

As is the case with other biopharmaceutical companies, our success is heavily dependent on intellectual property, particularly patents. Obtaining and enforcing patents in the biopharmaceutical industry involve both technological and legal complexity, and is therefore costly, time-consuming and inherently uncertain. In addition, the United States has enacted and is currently implementing the America Invents Act. Moreover, recent U.S. Supreme Court rulings have narrowed the scope of patent protection available in certain circumstances and weakened the rights of patent owners in other situations. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, this combination of events has created uncertainty with respect to the value of patents, once obtained. Depending on decisions by the U.S. Congress, the federal courts, and the USPTO, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future. For example, in the case of Assoc. for Molecular Pathology v. Myriad Genetics, Inc., the U.S. Supreme Court held that certain claims to DNA molecules are not patentable. We cannot predict how these decisions or any future decisions by the courts, the U.S. Congress or the USPTO may impact the value of our patents. Similarly, any adverse changes in the patent laws of other jurisdictions could adversely affect our business, results of operations and financial condition.

We have limited foreign intellectual property rights and may not be able to protect our intellectual property rights throughout the world.

We have limited intellectual property rights outside the United States. Filing, prosecuting and defending patents on product candidates in all countries throughout the world would be prohibitively expensive, and our intellectual property rights in some countries outside the United States can have a different scope and strength than those in the United States. Moreover, obtaining such protection in a timely manner, or at all, may be affected by factors or events beyond our control, such as a prolonged economic downturn, or global financial or political crises, whether or not related to the ongoing COVID-19 pandemic or the ongoing political unrest between Russia and the Ukraine. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the United States. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and, further, may export otherwise infringing products to territories where we have patent protection but where enforcement is not as strong as that in the United States. These products may compete with our products in jurisdictions where we do not have any issued patents and our patent claims or other intellectual property rights may not be effective or sufficient to prevent them from competing.

Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing

countries, do not favor the enforcement of patents, trade secrets and other intellectual property protection, particularly those relating to biopharmaceutical products, which could make it difficult for us to stop the infringement of our patents or marketing of competing products against third parties in violation of our proprietary rights generally. The initiation of proceedings by third parties to challenge the scope or validity of our patent rights in foreign jurisdictions could result in substantial cost and divert our efforts and attention from other aspects of our business. Proceedings to enforce our patent and other intellectual property rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate and the damages or other remedies awarded, if any, may not be commercially meaningful. Similarly, if our trade secrets are disclosed in a foreign jurisdiction, competitors worldwide could have access to our proprietary information and we may be without satisfactory recourse. Such disclosure could have a material adverse effect on our business. Moreover, our ability to protect and enforce our intellectual property rights may be adversely affected by unforeseen changes in foreign intellectual property laws. In addition, certain countries, including China and India, have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. In those countries, we and our licensors may have limited remedies if patents are infringed or if we or our licensors are compelled to grant a license to a third party, which could materially diminish the value of those patents. In addition, many countries limit the enforceability of patents against government authorities or government contractors. This could limit our potential revenue opportunities. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

We may incur substantial costs as a result of litigation or other proceedings relating to patents, and we may be unable to protect our rights to our products and technology.

If we or our licensors choose to go to court to stop a third-party from using the inventions claimed in our owned or in-licensed patents, that third-party may ask the court to rule that the patents are invalid and/or should not be enforced against that third-party. These lawsuits are expensive and would consume time and other resources even if we or they, as the case may be, were successful in stopping the infringement of these patents. In addition, there is a risk that the court will decide that these patents are not valid and that we or they, as the case may be, do not have the right to stop others from using the inventions. An adverse determination in any such proceeding could reduce the scope of, or invalidate, our patent rights, allow third parties to commercialize our technology or products and compete directly with us, without payment to us. An unfavorable result at the USPTO, EPO or other patent office may result in the loss of our right to exclude others from practicing one or more of our inventions in the relevant country or jurisdiction, which could adversely affect our business, results of operations and financial condition.

There also is the risk that, even if the validity of these patents is upheld, the court will refuse to stop the third-party on the ground that such third-party’s activities do not infringe our owned or in-licensed patents. In addition, the U.S. Supreme Court recently has changed some legal principles that affect patent applications, granted patents and assessment of the eligibility or validity of these patents. As a consequence, issued patents may be found to contain invalid claims according to the newly revised eligibility and validity standards. Some of our owned or in-licensed patents may be subject to challenge and subsequent invalidation or significant narrowing of claim scope in proceedings before the USPTO, or during litigation, under the revised criteria which also could make it more difficult to obtain patents.

We, or our licensors, may not be able to detect infringement against our owned or in-licensed patents, as the case may be, which may be especially difficult for manufacturing processes or formulation patents. Even if we or our licensors detect infringement by a third-party of our owned or in-licensed patents, we or our licensors, as the case may be, may choose not to pursue litigation against or settlement with the third-party. If we, or our licensors, later sue such third-party for patent infringement, the third-party may have certain legal defenses available to it, which otherwise would not be available except for the delay between when the infringement was

first detected and when the suit was brought. Such legal defenses may make it impossible for us or our licensors to enforce our owned or in-licensed patents, as the case may be, against such third-party.

If another party questions the patentability of any of our claims in our owned or in-licensed U.S. patents, the third-party can request that the USPTO review the patent claims such as in an inter partes review, ex parte re-exam or post-grant review proceedings. These proceedings are expensive and may result in a loss of scope of some claims or a loss of the entire patent. In addition to potential USPTO review proceedings, we may become a party to patent opposition proceedings at the EPO or similar proceedings in other foreign patent offices, where either our owned or in-licensed foreign patents are challenged.

In the future, we may be involved in similar proceedings challenging the patent rights of others, and the outcome of such proceedings is highly uncertain.

An adverse determination in any such proceeding may result in our inability to manufacture or commercialize products without infringing third-party patent rights. The costs of these opposition or similar proceedings could be substantial, and may result in a loss of scope of some claims or a loss of the entire patent.

Patent terms may be inadequate to protect our competitive position on our product candidates for an adequate amount of time.

Patents have a limited lifespan. In the United States, if all maintenance fees are timely paid, the natural expiration of a patent is generally 20 years from its earliest U.S. non-provisional application filing date. Various extensions such as patent term adjustments and/or extensions, may be available, but the life of a patent, and the protection it affords, is limited. For instance, a patent term extension based on regulatory delay may be available in the United States. However, only a single patent can be extended for each marketing approval, and any patent can be extended only once, for a single product. Moreover, the scope of protection during the period of the patent term extension does not necessarily extend to all claims, but instead only to claims that cover the product as approved. Even if patents covering our product candidates are obtained, once the patent life has expired, we may be open to competition from competitive products, including biosimilars. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to ours.

As of May 2, 2023, we own or in-license patent applications covering our proprietary technologies and our product candidates that if issued as patents are expected to expire between 2039 and 2044, without taking into account any possible patent term adjustments or extensions. However, the USPTO or relevant foreign patent offices may not grant any of these patent applications. If issued, the patents may expire before, or soon after, our first product achieves marketing approval in the United States or foreign jurisdictions. Further, if issued, the patents may expire before, or soon after, any regulatory protection afforded our first approved product through data and/or market exclusivity in the United States or foreign jurisdictions. Upon the expiration of any such patents, if issued, we may lose the right to exclude others from practicing these inventions. The expiration of these patents also could adversely affect our business, results of operations and financial condition.

If our trademarks and trade names are not adequately protected, then we may not be able to build name recognition in our markets of interest and our business, results of operations and financial condition could be adversely affected.

Our trademarks or trade names may be challenged, opposed, infringed, circumvented, invalidated, cancelled, declared generic, determined not to entitled to registration, or determined to be infringing on other marks. During trademark registration proceedings, we may receive rejections of our applications by the USPTO or in foreign jurisdictions. Although we would be given an opportunity to respond to those rejections, we may be

unable to overcome such rejections. In addition, in the USPTO and in comparable agencies in many foreign jurisdictions, third parties are given an opportunity to oppose pending trademark applications and to seek to cancel registered trademarks. Opposition or cancellation proceedings may be filed against our trademarks, and our trademarks may not survive such proceedings. Any trademark litigation could be expensive. In addition, we could be found liable for significant monetary damages, including treble damages, disgorgement of profits and attorneys’ fees, if we are found to have willfully infringed a trademark.

Moreover, any name we propose to use with our product candidates in the United States must be approved by the FDA, regardless of whether we have registered it, or applied to register it, as a trademark. Similar requirements exist in Europe. The FDA typically conducts a review of proposed product names, including an evaluation of potential for confusion with other product names. If the FDA (or an equivalent administrative body in a foreign jurisdiction) objects to any of our proposed proprietary product names, it may be required to expend significant additional resources in an effort to identify a suitable substitute name that would qualify under applicable trademark laws, not infringe the existing rights of third parties and be acceptable to the FDA. Furthermore, in many countries, owning and maintaining a trademark registration may not provide an adequate defense against a subsequent infringement claim asserted by the owner of a senior trademark.

We may not be able to protect our rights to our trademarks and trade names or may be forced to stop using these names, which we need for name recognition by potential partners or customers in our markets of interest. If we are unable to establish name recognition based on our trademarks and trade names, we may not be able to compete effectively and our business, results of operations and financial condition could be adversely affected.

Risks Related to Our Common Stock and This Offering

Prior to this offering there has been no public market for shares of our common stock. We have applied to list our common stock on Nasdaq under the symbol “TSBX.” However, no assurance can be given that our listing application will be approved. If our listing application is not approved by Nasdaq, we will not be able to consummate this offering. Although we have applied to list our common stock on Nasdaq, under the symbol “TSBX”, an active trading market for our shares may never develop or be sustained following this offering. You may not be able to sell your shares quickly or at the market price if trading in shares of our common stock is not active. The initial public offering price for our common stock will be determined through negotiations with the underwriters, and the negotiated price may not be indicative of the market price of the common stock after the offering. As a result of these and other factors, you may be unable to resell your shares of our common stock at or above the initial public offering price, at the time you wish to sell them, or at a price that you consider reasonable. The lack of an active market may also reduce the fair market value of your shares. Further, an inactive market also may impair our ability to raise capital by selling shares of our common stock and may impair our ability to enter into strategic partnerships or acquire companies or products by using our shares of common stock as consideration.

The price of our common stock may be volatile, and you could lose all or part of your investment.

The trading price of our common stock following this offering is likely to be highly volatile and could be subject to wide fluctuations in response to various factors, some of which are beyond our control, including limited trading volume. In addition to the factors discussed in this “Risk Factors” section and elsewhere in this prospectus, these factors include:

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the progress, conduct, enrollment or results of our two Phase 1 clinical trials for TIDAL-01;

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any termination of, loss of rights or disputes or disagreements arising under our collaboration, partnership and strategic alliance agreements;

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any delay in identifying additional product candidates from our current and future development programs;

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any delay in our regulatory filings for our product candidates and any adverse development or perceived adverse development with respect to the applicable regulatory authority’s review of such filings;

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adverse results or delays in future clinical trials;

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our decision to initiate a clinical trial, not to initiate a clinical trial or to terminate an existing clinical trial;

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adverse regulatory decisions, including failure to receive regulatory approval of our current product candidates or any future product candidate;

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changes in laws or regulations applicable to our current product candidates or any future product candidate, including but not limited to clinical trial requirements for approvals;

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adverse development concerning our competitors, particularly those developing TIL-based therapies;

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adverse developments concerning our manufacturers;

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adverse developments concerning our manufacturing process, including manufacturing failures;

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our inability to obtain adequate product supply for any approved product or inability to do so at acceptable prices;

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our inability to establish collaborations or other strategic relationships, if needed;

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our ability to successfully develop and the costs associated with the development of our internal manufacturing processes;

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our failure to commercialize our product candidates, if approved;

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additions or departures of key scientific or management personnel;

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unanticipated serious safety concerns related to the use of our current product candidates or any future product candidate;

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introduction of new products or services offered by us or our competitors;

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announcements of significant acquisitions, strategic partnerships, joint ventures or capital commitments by us or our competitors;

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our ability to effectively manage our growth;

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actual or anticipated variations in quarterly operating results;

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our cash position;

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our failure to meet the estimates and projections of the investment community or that we may otherwise provide to the public;

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publication of research reports about us or our industry, or our or a competitor’s product candidates in particular, or positive or negative recommendations or withdrawal of research coverage by securities analysts;

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changes in the market valuations of similar companies;

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volatility and instability in the financial and capital markets;

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overall performance of the equity markets, including the effects of geopolitical events;

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sales of our common stock by us, our insiders, or other stockholders in the future, or issuances by us of shares of our common stock in connection with strategic transactions;

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expiration of market standoff or lock-up agreements described in the section titled “Underwriting”;

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conditions and trends in the biotechnology and other industries;

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trading volume of our common stock;

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changes in accounting practices;

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ineffectiveness of our internal controls;

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disputes or other developments relating to intellectual property and other proprietary rights, including patents, litigation matters and our ability to obtain patent protection for our technologies;

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significant lawsuits, including patent or stockholder litigation;

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changes in the structure of healthcare payment systems, including coverage and adequate reimbursement for any approved drug;

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global or regional public health emergencies, including the ongoing COVID-19 pandemic or other pandemics, natural disasters, or major catastrophic events;

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adverse macroeconomic conditions or geopolitical events, including the COVID-19 pandemic, the conflict between Ukraine and Russia, and recent bank failures;

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the occurrence of any of the risks described in this section titled “Risk Factors”; and

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other events or factors, many of which are beyond our control.

In addition, the stock market in general, and the market for biotechnology companies in particular, have experienced extreme price and volume fluctuations that often have been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our common stock, regardless of our actual operating performance. If the market price of our common stock following this offering does not exceed the initial public offering price, you may not realize any return on your investment in our common stock and you may lose some or all of your investment. In the past, securities class action litigation often has been instituted against companies following periods of volatility in the market price of a company’s securities. This type of litigation, if instituted, could result in substantial costs and a diversion of management’s attention and resources, which could adversely affect our business, results of operations and financial condition.

We do not intend to pay dividends on our common stock so any returns will be limited to the value of our stock.

We currently anticipate that we will retain future earnings for the research, development, operation and expansion of our business and do not anticipate declaring or paying any cash dividends for the foreseeable future. Any future debt or other financing arrangements may contain terms prohibiting or limiting the amount of dividends that may be declared or paid on our common stock. Any return to stockholders therefore will be limited to the appreciation of in the price of our common stock.

Our principal stockholders and management own a significant percentage of our stock and will be able to exert significant control over matters subject to stockholder approval.

Based on 15,522,015 shares of our common stock outstanding as of March 31, 2023, after giving effect to the conversion of all outstanding shares of our convertible preferred stock into 12,493,879 shares of our common stock, prior to this offering, our executive officers, directors, holders of 5% or more of our capital stock and their respective affiliates beneficially owned approximately 43.3% of our voting stock. Immediately following the completion of this offering, our executive officers, directors, holders of 5% or more of our capital stock and their respective affiliates will beneficially hold, in the aggregate, approximately 35.9% of our outstanding common stock (assuming no exercise of the underwriters’ option to purchase additional shares of our common stock and no exercise of outstanding options). These stockholders, acting together, would be able to significantly influence all matters requiring stockholder approval. For example, these stockholders would be able to significantly influence elections of directors, amendments of our organizational documents, or approval of any merger, sale of assets, or other major corporate transaction. This level of control may prevent or discourage unsolicited acquisition proposals or offers for our common stock that you may feel are in your best interest as one of our stockholders. The significant concentration of stock ownership may adversely affect the trading price of our common stock due to investors’ perception that conflicts of interest may exist or arise.

Participation in this offering by certain of our directors and existing stockholders would reduce the available public float of our shares.

Certain of our directors and existing stockholders, including stockholders affiliated with our directors and who own 5% or more of our outstanding capital stock, have indicated an interest in purchasing shares of our common stock in this offering at the initial public offering price. However, because indications of interest are not binding agreements or commitments to purchase, the underwriters may determine to sell more, fewer or no shares in this offering to any of these directors or stockholders, or any of these directors or stockholders may determine to purchase more, fewer or no shares in this offering. To the extent these directors and existing stockholders purchase any shares in this offering, such purchase could reduce the available public float of our shares because such directors and stockholders may be restricted from selling the shares by restrictions under applicable securities laws. As a result, any purchase of shares by such directors and stockholders in this offering may reduce the liquidity of our common stock relative to what it would have been had these shares been purchased by investors that were not directors or existing stockholders.

If you purchase our common stock in this offering, you will incur immediate and substantial dilution in the book value of your shares.

The initial public offering price will be substantially higher than the pro forma as adjusted net tangible book value per share of our common stock after this offering. Investors purchasing common stock in this offering will pay a price per share that substantially exceeds the pro forma as adjusted net tangible book value per share after this offering. As a result, investors purchasing common stock in this offering will incur immediate dilution of $6.55 per share, based on an assumed initial public offering price of $13.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, representing the difference between our pro forma

as adjusted net tangible book value per share after giving effect to this offering and the assumed initial public offering price. Further, investors purchasing common stock in this offering will contribute approximately 30.5% of the total amount invested by stockholders since our inception, but will own only approximately 27.2% of the shares of common stock outstanding after this offering.

This dilution is due to our investors who purchased shares prior to this offering having paid substantially less when they purchased their shares than the price offered to the public in this offering. To the extent outstanding restricted stock awards vest or outstanding options are exercised, there will be further dilution to new investors. Additionally, pursuant to the Myst Merger Agreement, within 45 days of the closing of this offering, we will be obligated to pay the Myst Holders (as defined below) an aggregate amount equal to $3.0 million pursuant to the Myst Merger Agreement (as defined below). Further, within 45 days of the achievement of the third milestone under the Myst Merger Agreement, we are obligated to pay the Myst Holder an aggregate amount equal to $20.0 million. At our election, we may pay either of these milestone considerations in cash or in shares of our common stock. If we elect to pay the Myst Holders either of these milestone considerations, if and when achieved, in the form of shares of our common stock, then our existing stockholders will experience further dilution. As a result of the dilution to investors purchasing shares in this offering, investors may receive significantly less than the purchase price paid in this offering, if anything, in the event of our liquidation. For a further description of the dilution that you will experience immediately after this offering, see the section titled “Dilution.”

We are an emerging growth company and a smaller reporting company, and the reduced reporting requirements applicable to emerging growth companies and smaller reporting companies may make our common stock less attractive to investors.

We are an emerging growth company, as defined in the JOBS Act. For as long as we continue to be an emerging growth company, we may take advantage of exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies, including not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act, reduced disclosure obligations regarding executive compensation in this prospectus and our periodic reports and proxy statements, and exemptions from the requirements of holding nonbinding advisory votes on executive compensation and stockholder approval of any golden parachute payments not previously approved. We could be an emerging growth company for up to five years following the year in which we complete this offering, although circumstances could cause us to lose that status earlier. We will remain an emerging growth company until the earlier of (1) the last day of the fiscal year (a) following the fifth anniversary of the completion of this offering, (b) in which we have total annual gross revenue of at least $1.235 billion and (c) in which we are deemed to be a large accelerated filer, which requires the market value of our common stock that is held by non-affiliates to exceed $700.0 million as of the prior June 30th, and (2) the date on which we have issued more than $1.0 billion in non-convertible debt during the prior three-year period. Investors may find our common stock less attractive because we may rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

Under the JOBS Act, emerging growth companies also can delay adopting new or revised accounting standards until such time as those standards apply to private companies. We have elected to avail ourselves of this exemption, and, as a result, our operating results and financial statements may not be comparable to the operating results and financial statements of companies who have adopted the new or revised accounting standards.

We also are a “smaller reporting company,” meaning that the market value of our stock held by non-affiliates plus the proposed aggregate amount of gross proceeds to us as a result of this offering is less than $700.0 million and our annual revenue is less than $100.0 million during the most recently completed fiscal year. We may continue to be a smaller reporting company after this offering if either (i) the market value of our stock held by non-affiliates is less than $250.0 million or (ii) our annual revenue is less than $100.0 million during the

most recently completed fiscal year and the market value of our stock held by non-affiliates is less than $700.0 million. If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company we may choose to present only the two most recent fiscal years of audited financial statements in our annual report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.

Conflicts of interest may arise because some members of our board of directors are representatives of our principal stockholders.

Certain of our principal stockholders or their affiliates are venture capital funds or other investment vehicles that could invest in entities that directly or indirectly compete with us. As a result of these relationships, when conflicts arise between the interests of the principal stockholders or their affiliates and the interests of other stockholders, members of our board of directors that are representatives of the principal stockholders may not be disinterested.

Sales of a substantial number of shares of our common stock in the public market could cause our stock price to fall.

If our stockholders sell, or indicate an intention to sell, substantial amounts of our common stock in the public market after the lock-up and other legal restrictions on resale discussed in this prospectus lapse, the trading price of our common stock could decline. Based on shares of common stock outstanding as of March 31, 2023, upon the completion of this offering we will have outstanding a total of 21,322,015 shares of common stock. Of these shares, only the shares of common stock sold in this offering by us, plus any shares sold upon exercise of the underwriters’ option to purchase additional shares, will be freely tradable without restriction in the public market immediately following this offering.

The lock-up agreements pertaining to this offering will expire 180 days from the date of this prospectus, subject to earlier release of all or a portion of the shares at the sole discretion of BofA Securities, Inc., Leerink Partners LLC and Piper Sandler & Co. After the lock-up agreements expire, based upon the number of shares of common stock, on an as-converted basis, outstanding as of March 31, 2023, up to an additional 15,522,015 shares of common stock will be eligible for sale in the public market. Approximately 80.5% of these additional shares are beneficially held by directors, executive officers and their affiliates and will be subject to certain limitations of Rule 144 under the Securities Act of 1933, as amended, or the Securities Act. Pursuant to the Takeda Letter Agreement, Takeda has agreed to submit a non-binding indication of interest to participate in this offering by purchasing at the public offering price per share the number of shares of our common stock with an aggregate value of $8.0 million or such lesser amount as determined by us in our sole discretion, or the Takeda IPO Shares. The Takeda IPO Shares will not be subject to a lock-up agreement. Any transfers or sales of the Takeda IPO Shares may cause the price of our common stock to decline. Under the Takeda Agreement, Takeda’s original equity commitment of up to $20.0 million was partially fulfilled in June 2021 by Takeda’s purchase of 1,830,335 shares of our Series D preferred stock at a purchase price of $2.73174 per share for aggregate gross proceeds of approximately $5.0 million, and all of Takeda’s remaining obligations under the Takeda Agreement expired upon the termination the Takeda Agreement on July 6, 2023. Takeda’s agreement to participate in this offering or a concurrent private placement will expire on July 31, 2023. See the section titled “Certain Relationships and Related Party Transactions—Public Offering Participation Rights.”

In addition, shares of common stock that are either subject to outstanding options or reserved for future issuance under our existing equity compensation plans will become eligible for sale in the public market to the extent permitted by the provisions of various vesting schedules, the lock-up agreements and Rule 144 and Rule 701 under the Securities Act. If these additional shares of common stock are sold, or if it is perceived that they will be sold, in the public market, the trading price of our common stock could decline.

After this offering, the holders of 13,250,522 shares of our common stock will be entitled to rights with respect to the registration of their shares under the Securities Act as provided under the terms of the Second Amended and Restated Investors’ Rights Agreement, or the Rights Agreement, between us and the holders of our

convertible preferred stock, or in the case of Langer (as defined below), under the Myst Merger Agreement, in each case, subject to the 180-day lock-up agreements described above. See the section titled “Description of Capital Stock—Registration Rights.” Registration of these shares under the Securities Act would result in the shares becoming freely tradable without restriction under the Securities Act, except for shares held by affiliates, as defined in Rule 144 under the Securities Act. Any sales of securities by these stockholders could have a material adverse effect on the trading price of our common stock.

We have broad discretion in the use of our existing cash and the net proceeds from this offering and may not use them effectively.

Following this offering, our management will have broad discretion in the application of our existing cash and the net proceeds from this offering, including for any of the purposes described in the section titled “Use of Proceeds,” and you will not have the opportunity as part of your investment decision to assess whether such proceeds are being used appropriately. Because of the number and variability of factors that will determine our use of our existing cash and the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. Our management might not apply our existing cash and the net proceeds from this offering in ways that ultimately increase the value of your investment. The failure by our management to apply these funds effectively could harm our business. Pending their use, we may invest the net proceeds from this offering in short-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our stockholders. If we do not invest or apply the net proceeds from this offering in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

Anti-takeover provisions in our charter documents and under Delaware law could make an acquisition of our company more difficult, limit attempts by our stockholders to replace or remove our current management and limit the market price of our common stock.

Provisions in our amended and restated certificate of incorporation, as they will be in effect immediately following the closing of this offering, and our amended and restated bylaws, as they will be in effect immediately prior to the closing of this offering, may have the effect of delaying or preventing a change of control or changes in our board of directors and management. Our amended and restated certificate of incorporation and amended and restated bylaws will include provisions that:

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authorize our board of directors to issue, without further action by the stockholders, shares of undesignated preferred stock with terms, rights and preferences determined by our board of directors that may be senior to our common stock;

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require that any action to be taken by our stockholders be effected at a duly called annual or special meeting and not by written consent;

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specify that special meetings of our stockholders can be called only by directors representing a majority of the total authorized size of our board of directors, the chairperson of our board of directors, our chief executive officer or our president;

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establish an advance notice procedure for stockholder proposals to be brought before an annual meeting, including proposed nominations of persons for election to our board of directors;

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establish that our board of directors is divided into three classes, with each class serving three-year staggered terms;

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prohibit cumulative voting in the election of directors, therefore allowing the holders of a majority of the shares of common stock entitled to vote in any election of directors to elect all of the directors standing for election, if they should so choose;

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provide that our directors may be removed for cause only upon the vote of at least 66 2/3% of our outstanding shares of voting stock;

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provide that vacancies on our board of directors may be filled only by a majority of directors then in office, even though less than a quorum; and

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require the approval of our board of directors or the holders of at least 66 2/3% of our outstanding shares of voting stock to amend our bylaws and certain provisions of our certificate of incorporation.

These provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors, which is responsible for appointing the members of our management. In addition, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, or DGCL, which generally, subject to certain exceptions, prohibits a Delaware corporation from engaging in any of a broad range of business combinations with any “interested” stockholder for a period of three years following the date on which the stockholder became an “interested” stockholder. Any of the foregoing provisions could limit the price that investors might be willing to pay in the future for shares of our common stock, and they could deter potential acquirers of our company, thereby reducing the likelihood that holders of our common stock would receive a premium for their shares of our common stock in an acquisition.

Our amended and restated certificate of incorporation will provide that the Court of Chancery of the State of Delaware and the federal district court for the District of Delaware of the United States will be the exclusive forums for substantially all disputes between us and our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers, or employees.

Our amended and restated certificate of incorporation will provide that the Court of Chancery of the State of Delaware is the exclusive forum for the following types of actions or proceedings under Delaware statutory or common law:

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any derivative action or proceeding brought on our behalf;

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any action asserting a breach of fiduciary duty;

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any action asserting a claim against us arising under the DGCL, our amended and restated certificate of incorporation, or our amended and restated bylaws;

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any action seeking to interpret, apply, enforce or determine the validity of our amended and restated certificate of incorporation, or our amended and restated bylaws;

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any action to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware; and

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any action asserting a claim against us that is governed by the internal-affairs doctrine.

This provision would not apply to suits brought to enforce a duty or liability created by the Exchange Act. Furthermore, Section 22 of the Securities Act creates concurrent jurisdiction for federal and state courts over all such Securities Act actions. Accordingly, both state and federal courts have jurisdiction to entertain such claims. To prevent having to litigate claims in multiple jurisdictions and the threat of inconsistent or contrary rulings by different courts, among other considerations, our amended and restated certificate of incorporation will further provide that the federal district courts of the United States will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act. While the Delaware courts have determined that such choice of forum provisions are facially valid and several state trial courts have enforced such provisions and required that suits asserting Securities Act claims be filed in federal court, there is no guarantee that courts of appeal will affirm the enforceability of such provisions and a stockholder may nevertheless seek to bring a claim in a venue other than those designated in the exclusive forum provisions. In such instance, we would expect to vigorously assert the validity and enforceability of the exclusive forum provisions of our amended and restated certificate of incorporation. This may require significant additional costs

associated with resolving such action in other jurisdictions and the provisions may not be enforced by a court in those other jurisdictions. If a court were to find either exclusive forum provision in our amended and restated certificate of incorporation to be inapplicable or unenforceable in an action, we may incur further significant additional costs associated with litigating Securities Act claims in state court, or both state and federal court, which could seriously harm our business, results of operations and financial condition.

This exclusive forum provision may result in increased costs to stockholders to bring a claim. Further, this exclusive forum provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers, or other employees, which may discourage lawsuits against us and our directors, officers and other employees. If a court were to find either exclusive-forum provision in our amended and restated certificate of incorporation to be inapplicable or unenforceable in an action, we may incur further significant additional costs associated with resolving the dispute in other jurisdictions, all of which could seriously harm our business.

General Risk Factors

We will incur significant increased costs as a result of operating as a public company, and our management will be required to devote substantial time to new compliance initiatives.

As a public company, we will incur significant legal, accounting, compliance and other expenses that we did not incur as a private company. We will be subject to the reporting requirements of the Exchange Act, which will require, among other things, that we file with the SEC annual, quarterly, and current reports with respect to our business and financial condition. In addition, the Sarbanes-Oxley Act, as well as rules subsequently adopted by the SEC and Nasdaq to implement provisions of the Sarbanes-Oxley Act, impose significant requirements on public companies, including requiring establishment and maintenance of effective disclosure and financial controls and changes in corporate governance practices. Further, in July 2010, the Dodd-Frank Wall Street Reform and Consumer Protection Act, or the Dodd-Frank Act, was enacted. There are significant corporate governance and executive compensation related provisions in the Dodd-Frank Act that require the SEC to adopt additional rules and regulations in these areas such as “say on pay” and proxy access. Emerging growth companies and smaller reporting companies are exempted from certain of these requirements, but we may be required to implement these requirements sooner than budgeted or planned and thereby incur unexpected expenses. Stockholder activism, the current political environment and the current high level of government intervention and regulatory reform may lead to substantial new regulations and disclosure obligations, which may lead to additional compliance costs and impact the manner in which we operate our business in ways we cannot currently anticipate.

We expect the rules and regulations applicable to public companies to substantially increase our legal and financial compliance costs and to make some activities more time-consuming and costly. If these requirements divert the attention of our management and personnel from other business concerns, they could have a material adverse effect on our business, results of operations and financial condition. The increased costs will decrease our net income or increase our net loss, and may require us to reduce costs in other areas of our business or increase the prices of our products or services. For example, we expect these rules and regulations to make it more difficult and more expensive for us to obtain director and officer liability insurance and we may be required to incur substantial costs to maintain the same or similar coverage. We cannot predict or estimate the amount or timing of additional costs we may incur to respond to these requirements. The impact of these requirements also makes it more difficult for us to attract and retain qualified persons to serve on our board of directors, our board committees or as executive officers.

If we fail to maintain proper and effective internal control over financial reporting, our ability to produce accurate and timely financial statements could be impaired, investors may lose confidence in our financial reporting and the trading price of our common stock may decline.

We are not currently required to comply with the rules of the SEC implementing Section 404 of the Sarbanes-Oxley Act and are therefore not required to make a formal assessment of the effectiveness of our internal control over financial reporting for that purpose. Upon becoming a public company, we will be required to comply with the SEC’s rules implementing Sections 302 and 404 of the Sarbanes-Oxley Act, which will require management to certify financial and other information in our quarterly and annual reports and provide an annual management report on the effectiveness of internal control over financial reporting. Although we will be required to disclose changes made in our internal control over financial reporting on a quarterly basis, we will not be required to make our first annual assessment of our internal control over financial reporting until our second annual report on Form 10-K. However, as an emerging growth company, our independent registered public accounting firm will not be required to formally attest to the effectiveness of our internal control over financial reporting until the later of the year following our first annual report required to be filed with the SEC or the date we are no longer an emerging growth company. When we lose our status as an “emerging growth company” and reach an accelerated filer threshold, our independent registered public accounting firm will be required to attest to the effectiveness of our internal control over financial reporting. The rules governing the standards that must be met for our management to assess our internal control over financial reporting are complex and require significant documentation, testing and possible remediation. To comply with the requirements of being a reporting company under the Exchange Act, we may need to upgrade our information technology systems; implement additional financial and management controls, reporting systems and procedures; and hire additional accounting and finance staff. If we or, if required, our auditors are unable to conclude that our internal control over financial reporting is effective, investors may lose confidence in our financial reporting and the trading price of our common stock may decline.

There may be material weaknesses or significant deficiencies in our internal control over financial reporting in the future. Any failure to maintain internal control over financial reporting could severely inhibit our ability to accurately report our financial condition, results of operations or cash flows. If we are unable to conclude that our internal control over financial reporting is effective, or if our independent registered public accounting firm determines we have a material weakness or significant deficiency in our internal control over financial reporting once that firm begins its Section 404 reviews, investors may lose confidence in the accuracy and completeness of our financial reports, the market price of our common stock could decline, and we could be subject to sanctions or investigations by Nasdaq, the SEC or other regulatory authorities. Failure to remedy any material weakness in our internal control over financial reporting, or to implement or maintain other effective control systems required of public companies, could also restrict our future access to the capital markets.

Our disclosure controls and procedures may not prevent or detect all errors or acts of fraud.

Upon the completion of this offering, we will become subject to the periodic reporting requirements of the Exchange Act. We must design our disclosure controls and procedures to reasonably assure that information we must disclose in reports we file or submit under the Exchange Act is accumulated and communicated to management, and recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC. Any disclosure controls and procedures, no matter how well-conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met.

These inherent limitations include the realities that judgments in decision-making can be faulty, and that breakdowns can occur because of simple error or mistake. For example, our directors or executive officers could inadvertently fail to disclose a new relationship or arrangement causing us to fail to make any related party transaction disclosures. Additionally, controls can be circumvented by the individual acts of some persons, by collusion of two or more people or by an unauthorized override of the controls. Accordingly, because of the inherent limitations in our control system, misstatements due to error or fraud may occur and not be detected. In addition, we do not have a formal risk management program for identifying and addressing risks to our business in other areas.

We could be subject to securities class action litigation, which is expensive and could divert management attention.

The market price of our common stock is likely to be volatile. The stock market in general, and Nasdaq and biotechnology companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of companies. In the past, securities class action litigation has often been brought against a company following a decline in the market price of its securities. This risk is especially relevant for us because biotechnology companies have experienced significant stock price volatility in recent years. If we face such litigation, it could result in substantial costs (including the cost to defend against, and any potential adverse outcome resulting from any such proceeding), damage to our reputation, and a diversion of management’s attention and resources from other business concerns, which could harm our business.

Our failure to meet Nasdaq’s continued listing requirements could result in a delisting of our common stock.

If we are approved for listing, and after listing we fail to satisfy the continued listing requirements of Nasdaq, such as the corporate governance requirements or the minimum closing bid price requirement, Nasdaq may take steps to delist our common stock. Such a delisting would likely have a negative effect on the price of our common stock and would impair your ability to sell or purchase our common stock when you wish to do so. In the event of a delisting, we can provide no assurance that any action taken by us to restore compliance with listing requirements would allow our common stock to become listed again, stabilize the market price or improve the liquidity of our common stock, prevent our common stock from dropping below the Nasdaq minimum bid price requirement or prevent future non-compliance with the listing requirements of Nasdaq.

If securities or industry analysts do not publish research or publish inaccurate or unfavorable research about our business, our stock price and trading volume could decline.

The trading market for our common stock will depend in part on the research and reports that securities or industry analysts publish about us or our business. Securities and industry analysts do not currently, and may never, publish research on our company. If no securities or industry analysts commence coverage of our company, the trading price for our stock would likely be negatively impacted. In the event securities or industry analysts initiate coverage, if one or more of the analysts who covers us downgrades our stock or publishes inaccurate or unfavorable research about our business, our stock price would likely decline. If one or more of these analysts ceases coverage of our company or fails to publish reports on us regularly, demand for our stock could decrease, which would likely cause our stock price and trading volume to decline.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus contains forward-looking statements about us and our industry. All statements other than statements of historical facts contained in this prospectus, including statements regarding our future results of operations and financial position, business strategy, research and development costs; the anticipated timing, costs and conduct of preclinical studies and clinical trials for our Selected TIL programs and product candidates; the timing and likelihood of regulatory filings and approvals for our product candidates; our ability to commercialize our product candidates, if approved; the potential benefits of our strategic collaborations and our ability to enter into strategic arrangements; the timing and likelihood of success, plans and objectives of management for future operations; future results of anticipated product development efforts; our expected future financing needs; and expected uses of the net proceeds from this offering, are forward-looking statements. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplate,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions. The forward-looking statements in this prospectus are only predictions. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, results of operations and financial condition. These forward-looking statements speak only as of the date of this prospectus and are subject to a number of risks, uncertainties and assumptions described under the sections titled “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and elsewhere in this prospectus. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond our control, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. Except as required by applicable law, we undertake no obligation to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. You should, however, review the factors and risks we describe in the reports we will file from time to time with the SEC after the date of this prospectus. See the section titled “Where You Can Find More Information.”

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based on information available to us as of the date of this prospectus, and while we believe such information provides a reasonable basis for these statements, such information may be limited or incomplete. Our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and you are cautioned not to unduly rely on these statements.

MARKET, INDUSTRY AND OTHER DATA

We obtained the market, industry and statistical data in this prospectus from our own internal estimates and research as well as from industry and general publications and research, surveys and studies conducted by third parties. All of the market data used in this prospectus involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such data. While we believe that each of these studies and publications is reliable, the industry in which we operate is subject to a high degree of uncertainty and risk due to a variety of important factors, including those described in the section titled “Risk Factors.” These and other factors could cause results to differ materially from those expressed in the estimates made by third parties and by us.

USE OF PROCEEDS

We estimate that the net proceeds from our issuance and sale of 5,800,000 shares of our common stock in this offering will be approximately $65.8 million (or approximately $76.3 million if the underwriters exercise their option to purchase additional shares in full), after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us, assuming an initial public offering price of $13.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

Each $1.00 increase or decrease in the assumed initial public offering price of $13.00 per share, the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease, as applicable, the net proceeds to us from this offering by approximately $5.4 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. We may also increase or decrease the number of shares we are offering. Each 1,000,000 share increase or decrease in the number of shares offered by us would increase or decrease, as applicable, the net proceeds to us from this offering by approximately $12.1 million, assuming that the assumed initial offering price to the public remains the same, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. We do not expect that a change in the initial price to the public or the number of shares by these amounts would have a material effect on the uses of the proceeds from this offering, although it may accelerate the time at which we will need to seek additional capital.

The principal purposes of this offering are to increase our financial flexibility, create a public market for our common stock, and facilitate our future access to capital markets.

We intend to use the net proceeds from this offering, together with our existing cash, cash equivalents and short-term investments, as follows:

•

approximately $70 million to $75 million to fund the continued development of TIDAL-01 in our two Phase 1 clinical trials for the treatment of breast cancer, colorectal cancer, uveal melanoma and other non-cutaneous and cutaneous melanomas, through initial clinical data update in mid-2024 and continued development into the second quarter of 2025;

•

approximately $15 million to $20 million to advance our TIDAL-02 program through candidate declaration and TIDAL-01 and viral immunotherapy combination program through an investigational new drug application, or IND; and

•

remaining proceeds, if any, for working capital and general corporate purposes.

We may also use a portion of the remaining net proceeds and our existing cash, cash equivalents and short-term investments, to in-license, acquire, or invest in complementary businesses, technologies, products, or assets. However, we have no current commitments or obligations to do so.

We believe that the net proceeds of this offering, together with our existing cash, cash equivalents and short-term investments will enable us to fund our operations into the second quarter of 2025. In particular, we expect that the net proceeds from this offering, together with our existing cash, cash equivalents and short-term investments, will allow us to fund the continued development of TIDAL-01 in our two Phase 1 clinical trials for the treatment of breast cancer, colorectal cancer, uveal melanoma and other non-cutaneous and cutaneous melanomas, and to advance our TIDAL-02 program and TIDAL-01 and viral immunotherapy combination program. We have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we expect. This expected use of net proceeds from this offering and our existing cash, cash equivalents and short-term investments represents our intentions based upon our current plans

and business conditions, which could change in the future as our plans and business conditions evolve. Predicting the costs necessary to develop product candidates can be difficult and we anticipate that we will need additional funds to complete our clinical development of any of our product candidates. The amounts and timing of our actual expenditures may vary significantly depending on numerous factors, including the progress of our development, the status of and results from clinical trials, as well as any collaborations that we may enter into with third parties for our product candidates, and any unforeseen cash needs.

Our management will have broad discretion in the application of the net proceeds from this offering, and investors will be relying on the judgment of our management regarding the application of those net proceeds. The timing and amount of our actual expenditures will be based on many factors, including cash flows from operations and the anticipated growth of our business. Pending these uses, we plan to invest these net proceeds in short-term, interest-bearing obligations, investment-grade instruments, certificates of deposit or direct or guaranteed obligations of the United States.

DIVIDEND POLICY

We have never declared or paid, and do not anticipate declaring or paying, in the foreseeable future, any cash dividends on our capital stock. We currently intend to retain all available funds and any future earnings to support our operations and finance the growth and development of our business. Any future determination related to our dividend policy will be made at the discretion of our board of directors and will depend upon, among other factors, our results of operations, financial condition, capital requirements, contractual restrictions, business prospects and other factors our board of directors may deem relevant.

CAPITALIZATION

The following table sets forth our cash, cash equivalents and short-term investments and capitalization as of March 31, 2023:

•

on an actual basis;

•

on a pro forma basis after giving effect to (i) the conversion of all outstanding shares of our convertible preferred stock into an aggregate of 12,493,879 shares of common stock and the related reclassification of the carrying value of our convertible preferred stock to permanent equity in connection with the closing of this offering and (ii) the filing and effectiveness of our amended and restated certificate of incorporation that will be in effect immediately following the closing of this offering; and

•

on a pro forma as adjusted basis to reflect (i) the pro forma adjustments set forth above and (ii) our issuance and sale of 5,800,000 shares of common stock in this offering at an assumed initial public offering price of $13.00 per share, which is midpoint of the price range set forth on the cover page of this prospectus, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

You should read the information in this table together with our consolidated financial statements and related notes included elsewhere in this prospectus and the sections titled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Description of Capital Stock.”


	As of March 31, 2023
	Actual			Pro Forma			Pro Forma As Adjusted⁽¹⁾
	(in thousands, except share and per share data) (unaudited)
Cash, cash equivalents and short-term investments	$	63,969		$	63,969		$	129,782

Redeemable convertible preferred stock, $0.001 par value per share, 99,791,338 shares authorized, issued and outstanding, actual; no shares authorized, issued or outstanding, pro forma and pro forma as adjusted	$	171,964		$	—		$	—
Stockholders’ (deficit) equity:
Preferred stock, $0.001 par value per share; no shares authorized, issued or outstanding, actual; 10,000,000 shares authorized and no shares issued or outstanding, pro forma and pro forma as adjusted		—			—			—
Common stock, $0.001 par value; 147,892,358 shares authorized, 3,028,136 shares issued and outstanding, actual; 490,000,000 shares authorized, 15,522,015 shares issued and outstanding, pro forma; and 490,000,000 shares authorized, 21,322,015 shares issued and outstanding, pro forma as adjusted		3			16			21
Additional paid-in capital		21,556			193,507			259,315
Accumulated other comprehensive loss		(292	)		(292	)		(292	)
Accumulated deficit		(121,490	)		(121,490	)		(121,490	)

Total stockholders’ (deficit) equity		(100,223	)		71,741			137,554

Total capitalization	$	71,741		$	71,741		$	137,554

(1)

The pro forma as adjusted information set forth above is illustrative only and will change based on the actual initial public offering price and other terms of this offering determined at pricing. Each $1.00 increase or decrease in the assumed initial public offering price of $13.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease,

as applicable, each of our pro forma as adjusted cash, cash equivalents and short-term investments, additional paid-in capital, total stockholders’ (deficit) equity and total capitalization by approximately $5.4 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. We may also increase or decrease the number of shares we are offering. Each 1,000,000 share increase or decrease in the number of shares offered by us would increase or decrease, as applicable, each of our pro forma as adjusted cash, cash equivalents and short-term investments, additional paid-in capital, total stockholders’ equity and total capitalization by approximately $12.1 million, assuming that the assumed initial offering price to the public remains the same, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

The outstanding share information in the table above is based on 15,522,015 shares of our common stock as of March 31, 2023, after giving effect to the conversion of all outstanding shares of our convertible preferred stock into 12,493,879 shares of our common stock in connection with the closing of this offering, and excludes:

•

2,495,301 shares of our common stock issuable upon the exercise of outstanding stock options as of March 31, 2023, with a weighted-average exercise price of $8.86 per share;

•

186,043 shares of our common stock issuable upon the exercise of outstanding stock options granted subsequent to March 31, 2023, with a weighted-average exercise price of $16.53 per share;

•

275,163 shares of our common stock reserved for future issuance to Moffitt contingent on the achievement of certain clinical and regulatory milestones pursuant to our Alliance Agreement with Moffitt;

•

2,722,887 shares of our common stock reserved for future issuance under our 2023 Plan, which will become effective upon the execution of the underwriting agreement for this offering, as well as any automatic increases in the number of shares of common stock reserved for future issuance under this plan; and

•

222,287 shares of our common stock reserved for future issuance under our ESPP, which will become effective upon the execution of the underwriting agreement for this offering, as well as any automatic increases in the number of shares of common stock reserved for future issuance under this plan.

DILUTION

If you invest in our common stock in this offering, your ownership interest will be immediately diluted to the extent of the difference between the initial public offering price per share and the pro forma as adjusted net tangible book value per share of our common stock after this offering.

As of March 31, 2023, we had a historical net tangible book value (deficit) of $(100.2) million, or $(33.10) per share of common stock. Our historical net tangible book value (deficit) per share represents total tangible assets less total liabilities and convertible preferred stock, which is not included within permanent equity, divided by the number of shares of our common stock outstanding as of March 31, 2023.

Our pro forma net tangible book value as of March 31, 2023, was $71.7 million, or $4.62 per share of our common stock. Pro forma net tangible book value represents the amount of our total tangible assets less our total liabilities, (i) the conversion of all outstanding shares of our convertible preferred stock into an aggregate of 12,493,879 shares of common stock and the related reclassification of the carrying value of our convertible preferred stock to permanent equity in connection with the closing of this offering and (ii) the filing and effectiveness of our amended and restated certificate of incorporation that will be in effect immediately following the closing of this offering. Pro forma net tangible book value per share represents pro forma net tangible book value divided by the total number of shares outstanding as of March 31, 2023, after giving effect to the pro forma adjustments described above.

After giving further effect to the sale of 5,800,000 shares of common stock in this offering at an assumed initial public offering price of $13.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us, our pro forma as adjusted net tangible book value as of March 31, 2023 would have been approximately $137.6 million, or approximately $6.45 per share. This amount represents an immediate increase in pro forma net tangible book value of $1.83 per share to our existing stockholders and immediate dilution of approximately $6.55 per share to new investors in this offering. We determine dilution by subtracting the as pro forma adjusted net tangible book value per share after this offering from the amount of cash that a new investor paid for a share of common stock in this offering.

The following table illustrates this dilution:


Assumed initial public offering price per share				$	13.00
Historical net tangible book value (deficit) per share as of March 31, 2023	$	(33.10	)
Increase per share attributable to the pro forma adjustments described above		37.72

Pro forma net tangible book value per share as of March 31, 2023		4.62
Increase per share attributable to this offering		1.83

Pro forma as adjusted net tangible book value per share after this offering				$	6.45

Dilution per share to new investors in this offering				$	6.55

The pro forma as adjusted dilution information discussed above is illustrative only and will change based on the actual initial public offering price and other terms of this offering determined at pricing. Each $1.00 increase or decrease in the assumed initial public offering price of $13.00 per share, the midpoint of the price range set forth on the cover page of this prospectus, would increase or decrease, as applicable, the pro forma as adjusted net tangible book value per share after this offering by $0.25 per share and the dilution per share to investors participating in this offering by $0.75 per share, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. We may also increase or decrease the number of shares we are offering. Each 1,000,000 share increase in the number of shares offered by us, as set forth on the

cover page of this prospectus, would increase the pro forma as adjusted net tangible book value per share after this offering by $0.25 and decrease the dilution per share to investors participating in this offering by $0.25, assuming that the assumed initial public offering price of $13.00 per share, the midpoint of the price range set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. Each 1,000,000 share decrease in the number of shares offered by us, as set forth on the cover page of this prospectus, would decrease the pro forma as adjusted net tangible book value per share after this offering by $0.28 and increase the dilution per share to new investors participating in this offering by $0.28, assuming that the assumed initial public offering price of $13.00 per share, the midpoint of the price range set forth on the cover page of this prospectus, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

If the underwriters exercise their option to purchase an additional 870,000 shares of our common stock in full, the pro forma as adjusted net tangible book value of our common stock would increase to $6.67 per share, representing an immediate increase in the pro forma net tangible book value per share to existing stockholders of $2.05 per share and an immediate dilution of $6.33 per share to investors participating in this offering, in each case assuming an initial public offering price of $13.00 per share, which is the midpoint of the price range set forth on the cover page of this prospectus.

The following table summarizes as of March 31, 2023 on the pro forma as adjusted basis described above, the number of shares of our common stock, the total consideration and the average price per share (i) paid to us by our existing stockholders and (ii) to be paid by investors purchasing our common stock in this offering at an assumed initial public offering price of $13.00 per share, the midpoint of the price range set forth on the cover page of this prospectus, before deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.


	Shares Purchased				Total Consideration				Weighted-Average Price Per Share
	Number		Percent		Amount		Percent		Weighted-Average Price Per Share
Existing stockholders		15,522,015		72.8%	$	172,664,000		69.6%	$	11.12
New investors		5,800,000		27.2%	$	75,400,000		30.4%	$	13.00

Total		21,322,015		100%	$	248,064,000		100%

The foregoing tables and calculations are based on 15,522,015 shares of our common stock as of March 31, 2023, after giving effect to the conversion of all outstanding shares of our convertible preferred stock into 12,493,879 shares of our common stock in connection with the closing of this offering, and excludes:

•

2,495,301 shares of our common stock issuable upon the exercise of outstanding stock options as of March 31, 2023, with a weighted-average exercise price of $8.86 per share;

•

186,043 shares of our common stock issuable upon the exercise of outstanding stock options granted subsequent to March 31, 2023, with a weighted-average exercise price of $16.53 per share;

•

275,163 shares of our common stock reserved for future issuance to Moffitt contingent on the achievement of certain clinical and regulatory milestones pursuant to our Alliance Agreement with Moffitt;

•

To the extent that any outstanding options are exercised or new options are issued under our stock-based compensation plans, or we issue additional shares of common stock in the future, there will be further dilution to investors participating in this offering. Additionally, pursuant to the Myst Merger Agreement, within 45 days of the closing of this offering, we will be obligated to pay the Myst Holders an aggregate amount equal to $3.0 million pursuant to the Myst Merger Agreement. Further, within 45 days of the achievement of the third milestone under the Myst Merger Agreement, we are obligated to pay the Myst Holder an aggregate amount equal to $20.0 million. At our election, we may pay either of these milestone considerations in cash or in shares of our common stock. If we elect to pay the Myst Holders either of these milestone considerations, if and when achieved, in the form of shares of our common stock, then our existing stockholders will experience further dilution.

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MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

You should read the following discussion and analysis of our financial condition and results of operations together with the section titled “Summary Consolidated Financial Data” and our consolidated financial statements and related notes and the other financial information included elsewhere in this prospectus. Some of the information contained in this discussion and analysis or set forth elsewhere in this prospectus, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in the “Risk Factors” section of this prospectus, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis. You should carefully read the “Risk Factors” section of this prospectus to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements. Please also see the section titled “Special Note Regarding Forward-Looking Statements.”

Overview

We are a clinical stage biotechnology company focused on developing new medicines to treat and cure patients with solid tumors. Approved immunotherapies represent a significant advancement in the treatment of solid tumors, but many patients either do not respond or experience relapsed disease following an initial response. We believe the most significant challenge to creating curative immunotherapies in these patients is the low numbers of T cells that can recognize and attack the tumor, which we refer to as tumor-reactive T cells. To address this problem, we are pioneering a differentiated approach to tumor infiltrating lymphocytes, or TILs. We are developing next generation TIL therapies by selecting the most potent (meaning able to mediate an anti-tumor response) and tumor-reactive T cells, which we refer to as Selected TILs. Unlike other approaches that rely on standard “bulk TILs” that have demonstrated objective responses in clinical trials only in limited tumor types, we are developing our Selected TILs for potential treatment across the majority of solid tumors. We have initiated two Phase 1 clinical trials for TIDAL-01, including a multi-site trial for the treatment of breast cancer, colorectal cancer, and uveal melanoma, and an investigator sponsored trial with H. Lee Moffitt Cancer Center and Research Institute, Inc., or Moffitt, in both cutaneous and non-cutaneous melanomas. We intend to provide an initial clinical update across these two trials in mid-2024. We discuss the nature of this investigator-sponsored trial, including how this trial differs from a clinical trial sponsored by our company, as well as our roles and responsibilities in the trial, in more detail below. We are also advancing our preclinical pipeline including TIDAL-02, our next Selected TIL program, and TIDAL-01 in combination with viral immunotherapy. We define objective response as a patient experiencing a partial response or complete response to any given therapy.

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LOGO

*	Investigator sponsored trial at Moffitt Cancer Center

Under our multi-site trial, we control all aspects of our trial including, but not limited to, study protocol development, patient selection and enrollment, regulatory interactions, data release, and manufacturing through our industrial contract development and manufacturing organization, or CDMO. Under the investigator sponsored trial, which is fully funded by us, Moffitt is solely responsible for regulatory interactions, trial conduct and manufacture of TIDAL-01 at the Moffitt Cancer Cell Therapy Facility, with input and support from us at Moffitt’s discretion. Investigators at Moffitt are also solely responsible for the design of the trial and patient

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selection and enrollment, where we remain in close contact with the investigators to provide our input if appropriate. Any data disclosures will be made in collaboration with us and any improvements to the TIDAL-01 manufacturing process are solely at our discretion. We intend to provide an initial clinical update across these two trials in mid-2024.

Our next Selected TIL program, TIDAL-02, is being designed to encompass a next generation streamlined manufacturing process for tumor-reactive T cells and additional modifications to enhance TIL quality and function (meaning the viability of the TILs and their ability to produce cytotoxic and immune activating cytokines). We believe that TIDAL-02 has the potential to address solid tumor indications that are distinct from and complementary to TIDAL-01. TIDAL-02 is currently in preclinical development.

In December 2018, we completed a corporate reorganization pursuant to which Turnstone Biologics Inc. merged with and into Turnstone Biologics Corp., a newly formed Delaware corporation, as the successor company. As a result of this reorganization, we changed our domicile from the country of Canada to the State of Delaware. Our headquarters are located in San Diego, California and we operate as one segment. Since our inception, we have devoted substantially all of our efforts and financial resources to organizing and staffing our company, business planning, raising capital, discovering product candidates and securing related intellectual property rights and conducting research and development activities for our Selected TIL programs and product candidates. We do not have any products approved for sale and we have not generated any revenue from product sales and have incurred overall net losses since our inception through March 31, 2023. We have funded our operations primarily through the sale of our convertible preferred stock and revenue from certain of our collaboration agreements. Since our inception, we have raised an aggregate of approximately $172.0 million of gross proceeds from the issuance and sale of shares of our convertible preferred stock and $190.0 million in upfront, non-refundable collaboration revenue from the AbbVie Agreement and Takeda Agreement, each as defined below. As of December 31, 2022 and March 31, 2023, we had cash, cash equivalents and short-term investments of $82.1 million and $64.0 million, respectively.

We have incurred significant operating losses in the past, and we expect to continue to incur significant operating losses for the foreseeable future. Our net loss was $30.8 million for the year ended December 31, 2022. We had net income of $0.1 million and net loss of $12.6 million for the three months ended March 31, 2023 and 2022, respectively. As of December 31, 2022 and March 31, 2023, we had an accumulated deficit of $121.6 million and $121.5 million, respectively. Substantially all of our operating losses result from expenses incurred in our research and development programs and from general and administrative costs associated with our operations. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current or future product candidates, and on our ability to enter into collaborations, strategic partnerships and alliances or marketing, distribution or licensing arrangements with third parties.

We expect to incur significant expenses and increasing operating losses for the foreseeable future as we continue the preclinical development, manufacturing and clinical development of, and seek regulatory approval for, our product candidates. In addition, we may incur expenses in connection with the in-license or acquisition of additional platform technologies and the development of any such product candidates. We also expect to incur additional costs associated with operating as a public company. Furthermore, our operating losses may fluctuate significantly from quarter to quarter and year to year due to timing of preclinical activities, clinical development and regulatory approval of our product candidates.

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We plan to fund future operations and future capital funding needs through equity and debt financings, licensing transactions, and collaborations or strategic partnerships with other companies. We can provide no assurance that financing will be available in the amounts we need or on terms acceptable to us, if at all. If we enter into licensing transactions, collaborations, strategic partnerships or similar agreements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to us and may reduce the value of our common stock. If we are not able to secure adequate additional funding, we may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, and suspend, delay or curtail our development programs. Any of these actions could materially harm our business.

Our innovative Selected TIL approach focuses on selecting and manufacturing the most potent tumor-reactive T cells to overcome the limitations of bulk TILs. This approach is grounded on work conducted in academia that has demonstrated improved clinical responses for selected TILs in solid tumor types where bulk TILs have shown limited to no objective responses in clinical trials. We are leveraging this work to establish a standardized manufacturing process for large scale production of our Selected TILs. We intend to establish in-house tumor sequencing capabilities, expedite manufacturing and shipping of peptides, and biopsy tumor prior to resection to enable earlier sequencing and peptide synthesis.

Macroeconomic and Geopolitical Trends

We continue to actively monitor the impact of various macroeconomic and geopolitical trends, such as high rates of inflation, supply chain disruptions and geopolitical instability, bank failures, and the COVID-19 pandemic on our business. To date, we have not experienced a material financial statement impact or business disruptions, including with our vendors or third parties, as a result of these negative macroeconomic or geopolitical trends. Our business has been, and may continue to be, impacted by the negative macroeconomic and geopolitical trends wherever we have clinical trial sites, contract manufacturing organizations, or CMOs, facilities or other business operations.

Global economic and business activities continue to face widespread uncertainties, and global credit and financial markets have experienced extreme volatility and disruptions in the past several years, including severely diminished liquidity and credit availability, rising inflation and monetary supply shifts, rising interest rates, labor shortages, declines in consumer confidence, declines in economic growth, increases in unemployment rates, recession risks, and uncertainty about economic and geopolitical stability. Moreover, negative macroeconomic conditions could adversely impact our ability to obtain financing in the future on terms acceptable to us, or at all. In addition, the geopolitical instability and related sanctions could continue to have significant ramifications on global financial markets, including volatility in the U.S. and global financial markets.

To date, the COVID-19 pandemic has not had a material adverse impact on our productivity or our business, and as of March 31, 2023, we have not identified any significant disruption or impairment of our assets due to the pandemic. However, as COVID-19 transitions from a pandemic to an endemic, we cannot predict the potential future impacts of COVID-19 on us and third parties with whom we conduct business. These impacts will depend on future developments that are highly uncertain and cannot be predicted at this time. Given these uncertainties, COVID-19 could impact our business operations and our ability to execute on our associated business strategies and initiatives, and adversely impact our results of operations and our financial condition in the future, and could disrupt the business of third parties with whom we do business. We will continue to closely monitor and evaluate the nature and extent of the impacts of COVID-19 on our business, financial condition, results of operations, and prospects.

Collaboration Agreements

Below is a summary of the key terms for certain of our collaboration agreements. For a more detailed description of our collaboration agreements, see the section titled “Business—Collaboration Agreements” and

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Note 6 to our consolidated financial statements and Note 6 to our unaudited interim consolidated financial statements, each included elsewhere in this prospectus.

Moffitt Collaboration Agreements

Master Collaboration Agreement

In January 2021, we entered into an amended and restated master collaboration agreement, or the Moffitt Agreement, with Moffitt, to amend a then-existing master collaboration agreement from November 2019, as amended March 2020, between Moffitt and our now wholly-owned subsidiary, Myst Therapeutics LLC, with the intent to continue to work collaboratively in the research of cancer immunotherapies.

Moffitt granted us (1) a royalty-free, sublicensable, non-transferable, perpetual, non-exclusive license to use and practice certain inventions invented solely by Moffitt in the performance of a research plan or through use of any data generated thereunder, or Moffitt Inventions, (a) for internal, non-commercial research purposes outside the field of adoptive cell therapy and/or (b) to research, develop, make, use, sell, offer to sell, or import products and/or services in the field of adoptive cell therapy and (2) a royalty free, sublicensable, non-transferable, perpetual, non-exclusive license to use and practice certain inventions invented in performance of a research plan or through the use of Moffitt research materials, which are (i) specifically directed to the identity of melanoma-specific T cell receptors, (ii) invented during the collaboration term or within one year after the end of the collaboration term within the field of adoptive cell therapy, and (iii) invented solely by either parties’ employees or by both parties’ employees jointly, to research, develop, make, use, sell, offer to sell, or import products and/or services for cancer immunotherapy involving identifying relevant tumor reactive T cells from TILs.

Moffitt Alliance Agreement

In June 2022, we entered into a life science alliance agreement with Moffitt, or the Alliance Agreement, in order to further expand our relationship and support our existing agreements with Moffitt, or the Underlying Agreements. Pursuant to the Alliance Agreement, we will have priority access to Moffitt’s scientific research, manufacturing, and clinical capabilities for the development of novel TIL therapies, including expedited clinical trial activation, enhanced patient screening and data sharing, access to Moffitt’s cellular therapies research and development infrastructure, expanded molecular data sets and biospecimens for research, and allocated cGMP manufacturing capacity for our product candidates.

Under the Alliance Agreement, we are obligated to use commercially reasonable efforts to further develop TIL Products (as defined below), to manufacture TIL Products, to obtain regulatory approval for at least one TIL Product in the United States and to commercialize TIL Products in all countries in which regulatory approval for a TIL Product has been obtained. For purposes of the Alliance Agreement, TIL Product means any pharmaceutical, biopharmaceutical, or biotechnology TIL product that has been developed by us or Moffitt and is advanced into clinical development under an IND sponsored by Moffitt.

Pursuant to the Alliance Agreement, we have agreed to pay to Moffitt a total amount of at least $17.5 million, or the Alliance Funding Amount, for research, development and manufacturing related services that will be paid in five equal annual installments on June 1 of each year starting on June 1, 2023. However, the aggregate amounts we pay to Moffitt for all fees, costs, expenses and other payments pursuant to any Underlying Agreement with Moffitt entered into subsequent to February 7, 2022 may be credited against the Alliance Funding Amount. This reimbursement amount will be calculated annually at the conclusion of each payment period, and, to the extent our annual aggregate payments to Moffitt exceed the applicable annual installment amount, we will receive a reduction in the amount due for future installment payments based on a predetermined formula agreed to by the parties.

In connection with the execution of the Alliance Agreement, we issued Moffitt 91,721 shares of our common stock. As partial consideration under the Alliance Agreement, we also agreed to issue Moffitt an additional

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366,884 shares of our common stock in the aggregate upon the satisfaction of certain clinical and regulatory milestones with respect to TIL Products. During the three months ended March 31, 2023, an additional 91,721 shares of our common stock were issued to Moffitt as a result of the achievement of the milestone related to the start of the Phase 1 clinical trial for a TIL Product. In addition, upon achievement of certain thresholds for aggregate net sales of all TIL Products, we are required to make tiered sales-based milestones payments to Moffitt of up to an aggregate of $50.0 million. With respect to each of the equity and sales milestones described above, TIL Products include any pharmaceutical, biopharmaceutical or biotechnology TIL product that is developed by us or Moffitt and is advanced into clinical development under an IND sponsored by Moffitt.

Components of Our Results of Operations

Revenue

Collaboration Revenue

We enter into collaboration arrangements that may include the receipt of payments for up-front fees, success-based milestones, option exercises, intellectual property rights, research services, product supplies, and royalties on any future sales of commercialized products that result from the collaborations.

AbbVie Biotechnology Ltd.

In September 2017, we entered into a research, option, and license agreement, or the AbbVie Agreement, with AbbVie Biotechnology Ltd., or AbbVie, for the development of up to three pharmaceutical product candidates, based on our engineered MG1 Maraba virus. In April 2021, AbbVie provided us written notice to terminate the AbbVie Agreement, in accordance with its termination for convenience rights. AbbVie did not provide a reason for termination of the AbbVie Agreement and, to our knowledge, AbbVie has not publicly disclosed the reasons for such termination. The AbbVie Agreement terminated in June 2021. One of the product candidates would carry the tumor-associated antigen MAGEA3, and the other two product candidates would carry a tumor-associated antigen selected by AbbVie, a tumor-associated immune agent selected by us or AbbVie, or both an antigen and immune agent. We were primarily responsible for funding the initial research and development activities for each product candidate, which consisted of the completion of two Phase 1/2 clinical trials for MG1-MAGEA3 and the research and preclinical development of the other two product candidates. Pursuant to the AbbVie Agreement, AbbVie paid us a nonrefundable up-front payment of $90.0 million.

The AbbVie Agreement accounted for 0% and 69% of our total collaboration revenue for the years ended December 31, 2022 and 2021, respectively.

The AbbVie Agreement accounted for 0% of our total collaboration revenue for the three months ended March 31, 2023 and March 31, 2022. We will not receive any additional collaboration revenue under the AbbVie Agreement in the future because this agreement has been terminated.

Takeda Pharmaceutical Company Limited

In November 2019, we entered into a discovery, collaboration and license agreement, or the Takeda Agreement, with Millennium Pharmaceuticals, Inc. (also known as Takeda Oncology), a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited, or Takeda. Under the Takeda Agreement, Takeda paid us an upfront payment of $50.0 million and an additional upfront payment of $30.0 million for the option to license up to two selected discovery candidates, with additional consideration in the low to low-mid eight figures to be paid to us by Takeda for each exercise of such option.

The Takeda Agreement accounted for 100% and 31% of our total collaboration revenue for the years ended December 31, 2022 and 2021, respectively.

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The Takeda Agreement accounted for 100% of our total collaboration revenue for the three months ended March 31, 2023 and March 31, 2022.

On June 13, 2022, Takeda provided us with six months’ written notice to terminate the development program in accordance with its termination for convenience rights, with such termination being effective as of December 13, 2022. Upon the effective termination date of December 13, 2022, Takeda’s co-exclusive license to TBio-6517 terminated and we are no longer obligated to pursue development of TBio-6517. On January 6, 2023, Takeda provided us with six months’ written notice to terminate the remainder of the Takeda Agreement, in accordance with its termination for convenience rights, with such termination being effective as of July 6, 2023. Takeda has publicly stated that it terminated the Takeda Agreement for strategic reasons. As of March 31, 2023, we ceased all work under the Takeda Agreement and we have concluded that there are no remaining estimated services associated with the obligations under the Takeda Agreement as of the effective date of termination of the Takeda Agreement in its entirety. We will not receive any additional collaboration revenue under the Takeda Agreement in the future because this agreement has been terminated.

In determining the appropriate amount of revenue to be recognized as we fulfilled our obligations under our agreements, we performed the following steps: (1) identification of the promised goods or services in the contract; (2) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (3) measurement of the transaction price, including the constraint on variable consideration; (4) allocation of the transaction price to the performance obligations based on estimated selling prices; and (5) determining the pattern of recognition of revenue when we satisfy each performance obligation.

Pursuant to the Takeda Letter Agreement, Takeda has agreed to submit a non-binding indication of interest to participate in this offering by purchasing at the public offering price per share the number of shares of our common stock with an aggregate value of $8.0 million or such lesser amount as determined by us in our sole discretion, or the Takeda IPO Shares. Under the Takeda Agreement, Takeda’s original equity commitment of up to $20.0 million was partially fulfilled by Takeda’s purchase in June 2021 of 1,830,335 shares of our Series D preferred stock at a purchase price of $2.73174 per share for aggregate gross proceeds of approximately $5.0 million, and all of Takeda’s remaining obligations under the Takeda Agreement expired upon the termination of the Takeda Agreement on July 6, 2023. If Takeda decides to participate in this offering pursuant to the Takeda Letter Agreement, then they must purchase our common stock in this offering at the public offering price, subject to compliance with applicable securities laws. If Takeda does not participate in this offering, the underwriters determine it is not advisable for Takeda to participate in this offering, or Takeda’s participation in this offering is prohibited under U.S. federal securities laws or any other applicable laws, then, Takeda is obligated to purchase at the public offering price per share an aggregate number of shares of our common stock equal to the number of Takeda IPO Shares in a private placement contemporaneous with and conditioned on this offering. Takeda’s agreement to participate in this offering or a concurrent private placement will expire on July 31, 2023.

In addition, if Takeda does not submit an indication of interest to participate in this offering, unless we determine otherwise, in our sole discretion, then we shall sell and Takeda shall purchase in a private placement effected substantially concurrent with this public offering such number of our common shares equal to the number of Takeda IPO Shares at the public offering price. The closing of this public offering is a condition precedent to the closing of the private placement.

Operating Expenses

Research and Development Expenses

Research and development expenses consist primarily of external and internal costs incurred for our research and development activities, including adjusted development of our platform, our product discovery efforts and the development of our future product candidates. We expense research and development costs as incurred.

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External costs include:

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clinical trial expenses, including costs of third-party CROs and costs of performing toxicity studies;

•

expenses to acquire technologies to be used in research and development;

•

manufacturing scale-up expenses and the cost of acquiring and manufacturing preclinical and clinical materials and developing manufacturing processes; and

•

costs related to compliance with regulatory requirements.

Internal costs include:

•

employee-related expenses, which include salaries, benefits and stock-based compensation for employees engaged in research and development functions; and

•

facility-related and other allocated expenses, which include direct and allocated expenses for rent and maintenance of facilities, depreciation and amortization expense and expenses related to other general support services and supplies.

Costs for external development activities are recognized based on an evaluation of the progress to completion of specific tasks using information provided to us by our vendors and our clinical investigative sites. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses. Non-refundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses and expensed as the related goods are delivered or the services are performed.

The table below summarizes our research and development expenses incurred by major development program for the periods presented (in thousands):


	Year Ended December 31,				Three Months Ended March 31,
	2022		2021		2023		2022
RIVAL-01⁽¹⁾	$	32,078	$	32,692	$	644	$	9,659
TIDAL-01		36,542		14,054		11,045		4,655
TIDAL-02		5,893		—		1,940		740
Other programs		12,190		8,008		2,039		3,647

Total research and development	$	86,703	$	54,754	$	15,668	$	18,701

(1)	We pursued this development program pursuant to the Takeda Agreement. As the Takeda Agreement has been terminated, effective July 6, 2023, there will be no additional research and development expenses associated with this development program.

The successful development of our product candidates is highly uncertain. We plan to substantially increase our research and development expenses for the foreseeable future as we continue our existing clinical trials, initiate future clinical trials for our product candidates, continue to discover and develop additional product candidates, improve the efficiency and scalability of our manufacturing processes and supply chain and build our in-house process development, analytical and manufacturing capabilities. Therefore, we cannot reasonably estimate or know the nature, timing and estimated costs of the efforts that will be necessary to complete the development and commercialization of any of our product candidates. We are also unable to predict when, if ever, material net cash inflows will commence from the sale of our current or any future product candidates, if

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approved. This is due to the numerous risks and uncertainties associated with developing product candidates, including the uncertainty of:

•

the scope, rate of progress and expenses of our planned clinical trials and other research and development activities;

•

successful patient enrollment in, and the initiation and completion of, clinical trials, including the impact of patient discontinuations, the number and location of clinical sites, and our ability to manufacture Selected TILs efficiently;

•

establishing an appropriate safety profile of our product candidates;

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whether our product candidates show safety and efficacy in our clinical trials;

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receipt of marketing approvals from applicable regulatory authorities;

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making arrangements with third-party manufacturers for the supply of materials to support our planned clinical trials and establishing commercial manufacturing capabilities for the potential manufacture of approved products, if any;

•

obtaining, maintaining, protecting and enforcing patent and trade secret protection and regulatory exclusivity for our product candidates;

•

commercializing product candidates, if and when approved, whether alone or in collaboration with others; and

•

acceptable safety profile of the products following any regulatory approval.

Any changes in the outcome of any of these variables with respect to the development of our product candidates in preclinical and clinical development could mean a significant change in the costs and timing associated with the development of these product candidates. We may never succeed in achieving regulatory approval for any of our product candidates. We may obtain unexpected results from our clinical trials. We may elect to discontinue, delay or modify clinical trials of some product candidates or focus on others. For example, if the FDA or comparable foreign regulatory authority were to delay our planned clinical trials or require us to conduct pre-clinical or clinical trials beyond those that we currently expect or if we experience significant delays in enrollment in any of our planned clinical trials, we could be required to expend significant additional financial resources and time on the completion of clinical development of that product candidate.

General and Administrative Expenses

General and administrative expenses consist primarily of personnel costs, allocated expenses and other expenses for outside professional services, including legal, intellectual property, human resources, audit and accounting services. Personnel costs consist of salaries, bonuses, benefits and stock-based compensation.

We expect our general and administrative expenses will increase during the next few years to support our continued research and development activities of our product candidates and associated expenses with operating as a public company, including expenses related to compliance with the rules and regulations of the SEC and Nasdaq, insurance expenses, audit expenses, investor relations activities, Sarbanes-Oxley Act compliance expenses, increased costs related to the hiring of additional personnel and fees to outside consultants, lawyers and accountants, among other administrative expenses and professional services.

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Other Income (Expense), Net

Other income (expense), net consists primarily of interest income earned on our short-term investments and foreign currency remeasurement gains and losses.

Results of Operations

Comparison of the Three Months Ended March 31, 2023 and 2022

The following tables set forth our results of operations for the three months ended March 31, 2023 and 2022 (in thousands):


	Three Months Ended March 31,
	2023			2022			Change ($)
Collaboration revenue	$	19,306		$	10,718		$	8,588
Operating expenses:
Research and development		15,668			18,701			(3,033	)
General and administrative		4,032			4,698			(666	)

Total operating expenses		19,700			23,399			(3,699	)

Loss from operations		(394	)		(12,681	)		12,287
Other income (expense), net		380			85			295
Benefit (provision) for income taxes		82			(20	)		102

Net income (loss)	$	68		$	(12,616	)	$	12,684

Collaboration Revenue

Collaboration revenue was $19.3 million and $10.7 million during the three months ended March 31, 2023 and 2022, respectively, an increase of $8.6 million, or 80.1%. The change was primarily due to the recognition of deferred revenue as a result of the termination of the Takeda Agreement.

Research and Development Expenses

The following table summarizes our research and development expenses for the three months ended March 31, 2023 and 2022 (in thousands):


	Three Months Ended March 31,
	2023		2022
Pre-clinical	$	2,988	$	2,291
Manufacturing		5,697		10,976
Personnel related		4,778		4,615
Clinical and regulatory		2,205		819

Total research and development	$	15,668	$	18,701

Research and development expenses were $15.7 million and $18.7 million during the three months ended March 31, 2023 and 2022, respectively, a decrease of $3.0 million, or 16.2%. The decrease was due primarily to a decrease of $5.3 million in manufacturing expenses offset by increases of $0.7 million in preclinical research and development costs, $0.2 million in personnel-related costs, and $1.4 million in clinical and regulatory costs. Due to the termination of the Takeda Agreement and research and development activities

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thereunder, we expect research and development expenses to continue to decline in the near term; however, we expect our research and development expenses to increase in the long term as we advance the development of our product candidates.

General and Administrative Expenses

General and administrative expenses were $4.0 million and $4.7 million during the three months ended March 31, 2023 and 2022, respectively, a decrease of $0.7 million, or 14.2%. The decrease was due primarily to a decrease of $1.6 million in professional services due to hiring finance staff and less expenses incurred on intellectual property due to the termination of activities under the Takeda Agreement offset by increases of $0.4 million in facility, office and other operating costs due to the new San Diego office lease and $0.5 million in personnel-related costs due to increased finance headcount. We anticipate that general and administrative expenses will continue to increase in the future due to an increase in expenses related to activities associated with operating as a public company.

Other Income (Expense), Net

Other income (expense), net was $0.4 million and $0.1 million during the three months ended March 31, 2023 and 2022, respectively, an increase of $0.3 million, or 300%. The increase was primarily related to an increase in interest income, net of $0.3 million.

Comparison of the Year Ended December 31, 2022 and 2021

The following tables set forth our results of operations during the years ended December 31, 2022 and 2021 (in thousands):


	For the Year Ended December 31,
	2022			2021			Change ($)
Collaboration revenue	$	73,300		$	101,293		$	(27,993	)
Operating expenses:
Research and development		86,703			54,754			31,949
General and administrative		18,223			13,546			4,677

Total operating expenses		104,926			68,300			36,626

Income (loss) from operations		(31,626	)		32,993			(64,619	)
Other income (expense), net		933			708			225
Provision for income taxes		(141	)		(432	)		(291	)

Net income (loss)	$	(30,834	)	$	33,269		$	(64,103	)

Collaboration Revenue

Collaboration revenue was $73.3 million and $101.3 million during the years ended December 31, 2022 and 2021, respectively, a decrease of $28.0 million, or 27.6%. Collaboration revenue of $0.0 million and $73.3 million, and $69.8 million and $31.5 million, was recorded during the years ended December 31, 2022 and 2021, respectively, for each of the AbbVie Agreement and Takeda Agreement, respectively. The change was primarily due to the recognition of deferred revenue as a result of the terminations of the AbbVie Agreement in 2021 and the Takeda Agreement in 2022.

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Research and Development Expenses

The following table summarizes our research and development expenses during the years ended December 31, 2022 and 2021 (in thousands):


	Year Ended December 31,
	2022		2021
Pre-clinical research and development	$	19,530	$	8,269
Manufacturing		42,221		27,981
Personnel related		18,431		13,735
Clinical and regulatory		6,521		4,769

Total research and development	$	86,703	$	54,754

Research and development expenses were $86.7 million and $54.8 million during the years ended December 31, 2022 and 2021, respectively, an increase of $31.9 million, or 58.4%. The increase was due primarily to an increase of $11.3 million in preclinical research and development costs, an increase of $14.2 million in manufacturing expenses, an increase of $4.7 million in personnel-related costs, and an increase of $1.8 million in clinical and regulatory expenses. Based on stopping research and development activities on our RIVAL-01 program under the Takeda Agreement, we expect research and development expenses to decline in the near term; however, we expect our research and development expenses to increase in the long term as we advance the development of TIDAL-01.

General and Administrative Expenses

General and administrative expenses were $18.2 million and $13.5 million during the years ended December 31, 2022 and 2021, respectively, an increase of $4.7 million, or 34.5%. The increase was due primarily to increases of $0.7 million in professional service fees, $2.4 million in facility, office and other operating costs due to the new San Diego office lease and $1.6 million in personnel-related costs due to an increased headcount and stock-based compensation costs. We anticipate that general and administrative expenses will continue to increase in the future due to an increase in expenses related to activities associated with operating as a public company.

Other Income (Expense), Net

Other income (expense), net was $0.9 million and $0.7 million during the years ended December 31, 2022 and 2021, respectively, an increase of $0.2 million, or 31.8%. The increase was primarily related to an increase in interest income, net of $0.6 million, a gain on sale of assets in 2022 of $0.4 million and a decrease of $0.4 million in realized foreign exchange gains.

Liquidity and Capital Resources

Based on our expected operating losses and negative cash flows, we believe there is substantial doubt about our ability to continue as a going concern for 12 months after the date the unaudited interim consolidated financial statements for the three months ended March 31, 2023 included elsewhere in this prospectus were issued. If we cannot continue as a going concern, our stockholders may lose some or all of their investment in us. Our ability to continue as a going concern is dependent upon our ability to raise additional funding. We intend to raise additional capital through equity offerings, debt financings or other capital sources, including potential collaborations, licenses and other similar arrangements. However, we may not be able to secure additional financing in a timely manner or on favorable terms, if at all. Furthermore, if we issue equity securities to raise additional funds, our existing stockholders may experience dilution, and the new equity securities may have rights, preferences and privileges senior to those of our existing stockholders. If we raise additional funds

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through collaboration, licensing or other similar arrangements, we may need to relinquish valuable rights to our potential products on terms that are not favorable to use. If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we may need to significantly delay, scale back or discontinue the development or future commercialization of one or more of our product candidates, if approved, or one or more of our other research and development initiatives and we may need to undertake additional workforce reductions or restructuring activities in the future. Any of the above events could adversely affect our business, results of operations and financial condition and cause the price of our common stock to decline.

Sources of Liquidity

In December 2018, we completed a corporate reorganization pursuant to which Turnstone Biologics Inc. merged with and into Turnstone Biologics Corp., a newly formed Delaware corporation, as the successor company. As a result of this reorganization, we changed our domicile from the country of Canada to the State of Delaware. Our headquarters are located in San Diego, California and we operate as one segment. Since our inception, we have devoted substantially all of our efforts and financial resources to organizing and staffing our company, business planning, raising capital, discovering product candidates and securing related intellectual property rights and conducting research and development activities for our Selected TIL programs and product candidates. We do not have any products approved for sale, we have not generated any revenue from product sales, and we have incurred overall net losses since our inception through March 31, 2023. We did not incur net losses for the year ended December 31, 2021 and for the three months ended March 31, 2023 as a result of collaboration revenue from the AbbVie Agreement and Takeda Agreement. We have funded our operations primarily through the sale of our convertible preferred stock and revenue from certain of our collaboration agreements. Since our inception, we have raised an aggregate of approximately $172.0 million of gross proceeds from the issuance and sale of shares of our convertible preferred stock and $190.0 million in upfront, non-refundable collaboration revenue. As of December 31, 2022 and March 31, 2023, we had cash, cash equivalents and short-term investments of $82.1 million and $64.0 million, respectively.

We have incurred significant operating losses in the past and expect to continue to incur significant operating losses for the foreseeable future. Our net loss was $30.8 million for the year ended December 31, 2022 and we had $33.3 million of net income for the year ended December 31, 2021. Our net income was $0.1 million and net loss was $12.6 million for the three months ended March 31, 2023 and 2022, respectively. As of December 31, 2022 and March 31, 2023, we had an accumulated deficit of $121.6 million and $121.5 million, respectively. Substantially all of our operating losses result from expenses incurred in our research and development programs and from general and administrative costs associated with our operations. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current or future product candidates, and on our ability to enter into collaborations, strategic partnerships and alliances or marketing, distribution or licensing arrangements with third parties.

We expect that the net proceeds from this offering, together with our existing cash, cash equivalents and short-term investments, will enable us to fund our operating expenses and capital expenditure requirements into the second quarter of 2025. We have based this estimate on assumptions that may prove to be wrong, and we may use our available capital resources sooner than we currently expect.

Funding Requirements

We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we continue to advance our product candidates and programs through preclinical and clinical development. Furthermore, upon the completion of this offering, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs which could materially harm our business.

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Our future capital requirements will depend on many factors, including:

•

the costs of conducting clinical trials, including the clinical development of our TIDAL-01 product candidate;

•

the progress of preclinical development and clinical trials of our current earlier-stage and future product candidates;

•

the costs of manufacturing;

•

the scope, progress, results and costs of discovery, preclinical development, laboratory testing and clinical trials for other potential product candidates we may develop, if any;

•

the costs, timing and outcome of regulatory review of our product candidates;

•

our ability to establish and maintain collaborations and partnerships on favorable terms, if at all;

•

the achievement of milestones or occurrence of other developments that trigger payments under any collaboration agreements we might have at such time;

•

the costs of preparing, filing and prosecuting patent applications, obtaining, maintaining and enforcing our intellectual property rights and defending intellectual property-related claims;

•

the cost of operating as a public company;

•

the costs and timing of future commercialization activities, if any, including product sales, marketing, manufacturing and distribution, for any of our product candidates for which we receive marketing approval;

•

our ability to achieve sufficient market acceptance, adequate coverage and reimbursement from third-party payors and adequate market share; and

•

the amount of revenue, if any, received from commercial sales of our product candidates, should any of our product candidates receive marketing approval.

Identifying potential product candidates and conducting preclinical testing and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of products that we do not expect to be commercially available for many years, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all.

As of December 31, 2022 and March 31, 2023, we had cash, cash equivalents and short-term investments of $82.1 million and $64.0 million, respectively. We believe that the anticipated net proceeds from this offering, together with our existing cash, cash equivalents and short-term investments, will enable us to fund our operating expenses and capital expenditure requirements into the second quarter of 2025. We have based this estimate on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect. We anticipate that we will require additional capital as we seek regulatory approval of our product candidates and if we choose to pursue in-licenses or acquisitions of other product candidates. If we need to raise additional capital to fund our operations, funding may not be available to us on acceptable terms, or at all. If we are unable to obtain adequate financing when needed, we may have to delay, reduce the scope of, or suspend one

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or more of our preclinical studies, clinical trials, research and development programs, or commercialization efforts. If we receive regulatory approval for our current or future product candidates, we expect to incur significant commercialization expenses related to product manufacturing, sales, marketing and distribution, depending on where we choose to commercialize.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. We do not have any committed external source of funds. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interests may be diluted, and the terms of these securities may include liquidation or other preferences that could adversely affect your rights as a common stockholder. Debt financing, if available, may involve agreements that include restrictive covenants that limit our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends, that could adversely impact our ability to conduct our business.

If we raise funds through collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us. If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we may need to significantly delay, scale back or discontinue the development or future commercialization of one or more of our product candidates, if approved, or one or more of our other research and development initiatives and we may need to undertake additional workforce reductions or restructuring activities in the future. Any of the above events could adversely affect our business, results of operations and financial condition and cause the price of our common stock to decline.

Cash Flows

The following table summarizes our cash flows for the periods indicated (in thousands):


	Year Ended December 31,						Three Months Ended March 31,
	2022			2021			2023			2022
Cash used in operating activities	$	(71,062	)	$	(45,629	)		(17,170	)	$	(16,455	)
Cash provided by (used in) investing activities		(14,932	)		(3,348	)		16,500			(718	)
Cash provided by (used in) financing activities		(2,656	)		79,954			(815	)		10

Net increase (decrease) in cash, cash equivalents and restricted cash	$	(88,650	)	$	30,977		$	(1,485	)	$	(17,163	)

Cash Flows from Operating Activities

Cash used in operating activities for the three months ended March 31, 2023 was $17.2 million, primarily due to the decrease in our net operating assets and liabilities of $19.3 million, which included changes in deferred revenue of $19.3 million, accretion of the premium on short-term investments of $0.3 million and partially offset by changes in stock-based compensation of $1.0 million, depreciation and amortization expense of $0.7 million, change in the fair value of contingent consideration liabilities of $0.6 million and net income of $0.1 million.

Cash used in operating activities for the three months ended March 31, 2022 was $16.5 million, primarily due to our net loss of $12.6 million and change in our net operating assets and liabilities of $6.0 million which were partially offset by changes in stock-based compensation of $1.0 million, depreciation and amortization expense of $0.7 million, and change in the fair value of contingent consideration liabilities of $0.4 million.

Cash used in operating activities for the year ended December 31, 2022 was $71.1 million, primarily due to our net loss of $30.8 million and decrease in our net operating assets and liabilities of $58.0 million, which

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included changes in deferred revenue of $53.1 million, partially offset by changes in stock-based compensation and Moffitt performance awards of $6.4 million, depreciation and amortization expense of $3.9 million and change in the fair value of contingent consideration liabilities of $7.0 million.

Cash used in operating activities for the year ended December 31, 2021 was $45.6 million, primarily due to the decrease in our net operating assets and liabilities of $85.8 million which was partially offset by our net income of $33.3 million, stock-based compensation of $2.6 million, change in fair value of contingent consideration liability of $1.7 million and depreciation and amortization expense of $1.4 million.

Cash Flows from Investing Activities

Cash provided by investing activities for the three months ended March 31, 2023 was $16.5 million, due primarily to the maturities of $17.3 million of short-term investments, $0.1 million of proceeds from the sale of property and equipment, and $0.9 million in purchases of property and equipment.

Cash used in investing activities for the three months ended March 31, 2022 was $0.7 million, due primarily to the purchase of short-term investments of $13.1 million and $0.6 million in purchases of property and equipment offset by the maturities of short-term investments of $13.0 million.

Cash used in investing activities for the year ended December 31, 2022 was $14.9 million, due primarily to the maturities of $49.8 million of short-term investments, the purchase of short-term investments of $59.5 million, and $5.2 million in purchases of property and equipment.

Cash used in investing activities for the year ended December 31, 2021 was $3.3 million, due primarily to the maturities of $41.4 million of short-term investments, the purchase of short-term investments of $41.4 million, and $3.4 million in purchases of property and equipment.

Cash Flows from Financing Activities

Net cash used in financing activities for the three months ended March 31, 2023 was $0.8 million, due primarily to the $0.9 million cash payment of contingent consideration related to Myst’s achievement of the second milestone under the Myst Merger Agreement due to the acceptance by the FDA of an IND filed by, on behalf of or for the benefit of us.

Net cash provided by financing activities for the three months ended March 31, 2022 was $0.0 million.

Net cash used in financing activities for the year ended December 31, 2022 was $2.7 million, due primarily to the $0.2 million received from the exercise of stock options and $2.8 million payment of contingent consideration related to Myst’s achievement of the second milestone under the Myst Merger Agreement due to the acceptance by the FDA of an IND filed by, on behalf of or for the benefit of us.

Net cash provided by financing activities for the year ended December 31, 2021 was $80.0 million, due primarily to the $79.6 million net proceeds from the sale and issuance of Series D preferred stock and the $0.3 million received from the exercise of stock options.

Contractual Obligations and Commitments

We enter into contracts in the normal course of business with CROs and CMOs for clinical trials, preclinical research studies and testing, manufacturing and other services and products for operating purposes. These contracts provide for termination at the request of either party with less than one year notice, and therefore we believe that our non-cancelable obligations under these agreements are not material. We additionally have contractual obligations for our operating leases for our corporate headquarters and office and laboratory spaces.

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These obligations are further described in Note 11 to our consolidated financial statements and Note 11 to our unaudited interim consolidated financial statements, each included elsewhere in this prospectus. We are also party to certain collaboration and license agreements, which contain a number of contractual obligations. Those contractual obligations may entitle us to receive, or may obligate us to make, certain payments. The amount and timing of those payments are unknown or uncertain as we are unable to estimate the timing or likelihood of the events that will obligate those payments.

We have milestones, royalties, and/or other payments due to third parties under our existing license and collaboration agreements. See the section titled “Business—Collaboration Agreements” and Note 6 to our audited consolidated financial statements and Note 6 to our unaudited interim consolidated financial statements, each included elsewhere in this prospectus. We could not estimate when such payments will be due and none of these events were probable to occur as of December 31, 2022 and March 31, 2023, respectively.

Critical Accounting Polices and Estimates

The preparation of our financial statements and related disclosures in conformity with generally accepted accounting principles in the United States and our discussion and analysis of our financial condition and operating results require us to make judgments, assumptions and estimates that affect the amounts reported in our consolidated financial statements and accompanying notes. Our significant accounting policies and methods used in preparation of our consolidated financial statements are described in Note 2 to our audited consolidated financial statements and Note 2 to our unaudited interim consolidated financial statements, each included elsewhere in this prospectus. We base our estimates on historical experience and on various other assumptions we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ from these estimates, and such differences may be material.

We believe that the critical accounting policies and estimates discussed below are critical to understanding our historical and future performance, as these policies relate to the more significant areas involving our judgments and estimates.

Revenue Recognition

We entered into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments, full time equivalent based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations.

Effective January 1, 2017, we adopted the provisions of ASC Topic 606, Revenue from Contacts with Customers, or ASC 606. Under ASC 606, an entity recognizes revenue when our customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, we perform the following five steps: (i) identification of the contract(s) with the customer, (ii) identification of the promised goods or services in the contract and determination of whether the promised goods or services are performance obligations, (iii) measurement of the transaction price, (iv) allocation of the transaction price to the performance obligations, and (v) recognition of revenue when (or as) we satisfy each performance obligation. We only apply the five-step model to contracts when it is probable that the entity will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer.

We account for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations, (ii) each party’s rights regarding the goods or services to be transferred can be identified, (iii) the payment terms for the goods and services to be transferred can be identified, (iv) the

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arrangement has commercial substance and (v) collection of substantially all of the consideration to which we will be entitled in exchange for the goods or services that will be transferred to the customer is probable.

We estimate the transaction price based on the amount of consideration that we expect for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, we evaluate the amount of the potential payments and the likelihood that the payments will be received. We utilize either the most likely amount method or expected value method to estimate the transaction price based on which method better predicts the amount of consideration expected to be received. If it is probable that a significant revenue reversal would not occur, the variable consideration is included in the transaction price.

For arrangements that include development and regulatory milestone payments, we evaluate whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within our control or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, we re-evaluate the probability of achievement of such milestones and any related constraint, and if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenue and net income (loss) in the period of adjustment.

For sales-based royalties, including milestone payments based on the level of sales, we determine whether the sole or predominant item to which the royalties relate is a license. When the license is the sole or predominant item to which the sales-based royalty relates, we recognize revenue at the later of: (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied).

We allocate the transaction price based on the estimated standalone selling price. We must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. We utilize key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration related to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts we would expect to receive for each performance obligation.

For performance obligations, which consist of licenses and other promises, we utilize judgment to assess the nature of the combined performance obligation in order to determine whether the combined performance obligation is satisfied over time or at a point in time. We determine the appropriate method of measuring progress of combined performance obligations satisfied over time for purposes of recognizing revenue determined on a contract by contract basis. We evaluate the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the license to our intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we will recognize revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license.

We receive payments from customers based on billing schedules established in each contract. Up-front payments and fees are recorded as deferred revenue upon receipt or when due until we perform our obligations under these arrangements. Amounts are recorded as accounts receivable when our right to consideration is unconditional.

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Stock-Based Compensation

We measure the cost of employee, nonemployee and director services received in exchange for an award of equity instruments based on the fair value of the award on the date of grant and recognizes the related expense over the period during which the employee, nonemployee or director is required to provide service in exchange for the award on a straight-line basis.

We estimate the fair value of each award on the date of grant using the Black-Scholes option -pricing model. This model requires the use of highly subject assumptions to determine the fair value of each stock-based award, including:

•

Fair value of common stock. See the subsection titled “—Determination of the Fair Value of Common Stock” below.

•

Expected term. The expected term represents the period that the stock-based awards are expected to be outstanding. The expected term for our stock options was calculated based on the weighted-average vesting term of the awards and the contract period, or simplified method.

•

Expected volatility. Since we are not yet a public company and do not have any trading history for our common stock, the expected volatility was estimated based on the average historical volatilities of common stock of comparable publicly traded entities over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on their size, stage of their life cycle or area of specialty. We will continue to apply this process until enough historical information regarding the volatility of our stock price becomes available.

•

Risk-free interest rate. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options.

•

Expected dividend yield. We have never paid dividends on our common stock and have no plans to pay dividends on our common stock. Therefore, we used an expected dividend yield of zero.

The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate and (d) expected dividends. Due to the lack of a public market for our common stock and lack of company- specific historical and implied volatility data, we have based our computation of expected volatility on the historical volatility of a representative group of public companies with similar characteristics to us, including stage of product development and life science industry focus. The historical volatility is calculated based on a period of time commensurate with the expected term. We use the simplified method as prescribed by the SEC Staff Accounting Bulletin No. 107, Share-Based Payment, to calculate the expected term for options granted to our employees as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The expected term is applied to the stock option grant group as a whole, as we do not expect substantially different exercise or post-vesting termination behavior among our employee population. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. The expected dividend yield is assumed to be zero as we have never paid dividends and has no current plans to pay any dividends on our common stock.

See Note 2 to our audited consolidated financial statements and Note 2 to our unaudited interim consolidated financial statements, each included elsewhere in this prospectus, for information concerning certain of the specific assumptions we used in applying the Black-Scholes option pricing model to determine the estimated fair value of our stock options granted in the periods presented.

As of December 31, 2022 and March 31, 2023, there was $8.9 million and $7.7 million of total unrecognized stock-based compensation expense related to our granted options, which we expect to recognize over a remaining weighted-average period of 2.7 years and 2.5 years, respectively.

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The intrinsic value of all outstanding stock options as of March 31, 2023 was approximately $10.3 million, based on the assumed initial public offering price of $13.00 per share, which is the midpoint of the estimated offering price range set forth on the cover page of this prospectus, of which approximately $6.1 million related to vested stock options, and approximately $4.2 million related to unvested stock options.

Determination of the Fair Value of Common Stock

There are significant judgments and estimates inherent in the determination of the fair value of our common stock. These estimates and assumptions include a number of objective and subjective factors, including external market conditions, the prices at which we sold shares of our convertible preferred stock, the superior rights and preferences of securities senior to our common stock at the time of, and the likelihood of, achieving a liquidity event, such as an initial public offering or sale of the company.

As there has been no public market for our common stock prior to this offering, the estimated fair value of our common stock underlying our stock-based awards has been determined by our board of directors as of each option grant date with input from management, considering our most recently available third-party valuations of common stock and our board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent valuation through the date of the grant. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation, or the Practice Aid. In valuing our common stock, the equity value of the business was determined using the backsolve method, a form of the subject company transaction method, wherein the equity value for a privately held company is derived from a recent transaction in our securities. The value is then allocated using the hybrid method allocation methodology. For grants made prior to September 30, 2018, in accordance with the Practice Aid, we determined the option pricing method, or OPM, was the most appropriate method for determining the fair value of our common stock based on our stage of development and other relevant factors. For grants made subsequent to September 30, 2018, in accordance with Practice Aid, we used a hybrid method, which is a hybrid between the OPM and the probability-weighted expected return method, or PWERM. The hybrid method is a combination of the PWERM and OPM. The OPM allocates the overall company value to the various share classes based on differences in liquidation preferences, participation rights, dividend policy and conversion rights, using a series of call options. The call right is valued using a Black-Scholes option pricing model. The PWERM employs additional information not used in the OPM, including various market approach calculations depending upon the likelihood of various discrete future liquidity scenarios, such as an initial public offering or sale of the company, as well as the probability of remaining a private company. In a hybrid method, various exit scenarios are analyzed. A discount for lack of marketability of our common stock is then applied to arrive at an indication of value for the common stock.

In addition to considering the results of these third-party valuations, we considered various objective and subjective factors to determine the fair value of our common stock as of each grant date, which may be a date later than the most recent third-party valuation date, including:

•

the prices of our convertible preferred stock sold to outside investors in arm’s length transactions, and the rights, preferences and privileges of our convertible preferred stock as compared to those of our common stock, including the liquidation and redemption preferences of our convertible preferred stock;

•

the progress of our research and development efforts, including the status of preclinical studies and ongoing and planned clinical trials for our product candidates and progress of our development and manufacturing processes;

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our stage of development and our business strategy, and material risks related to our business;

•

the hiring of key personnel and management;

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•

external market conditions affecting the biotechnology industry, and trends within the biotechnology industry;

•

our financial position, including cash on hand, and our historical and forecasted performance and results of operations;

•

the lack of an active public market for our common stock and our convertible preferred stock;

•

the likelihood of achieving a liquidity event for the holders of our common stock, such as an initial public offering, or a sale of our company, given prevailing market conditions;

•

the achievement of enterprise milestones, including entering into collaboration and license agreements;

•

the analysis of initial public offerings and the market performance of similar companies in the biotechnology industry; and

•

the economy in general.

We also performed a retrospective review of common stock fair value when preparing for our financial statements audits and considered the amount of time between the independent third-party valuation dates and the grant dates. We performed an interpolation of the fair value between the two valuation dates if we concluded that a significant change in valuation had occurred between the previous valuation and the grant date due to significant business or market events. The incremental stock-based compensation expense recorded as a result of the retrospective review was insignificant.

The assumptions underlying these valuations represented management’s best estimate, which involved inherent uncertainties and the application of management’s judgment. As a result, if we used significantly different estimates and assumptions, our stock-based compensation expense could be materially different.

Following the completion of this offering, the fair value of our common stock will be determined based on the quoted market price of our common stock. In connection with this offering, all outstanding shares of our convertible preferred stock will be converted into shares of our common stock.

Contingent Consideration

Consideration paid related to the Myst Merger Agreement may include potential future payments that are contingent upon our achieving certain milestones in the future. Contingent consideration liabilities are measured at their estimated fair value as of the date of the consolidated balance sheets using a probability-based income approach based on the monetary value of the milestone payment discounted for the likelihood of achieving the milestone and a present value factor based on the timing of when the milestone is expected to be achieved.

Contingent consideration liabilities expected to be settled within 12 months after the balance sheet date are presented in current liabilities, with the non-current portion recorded under other liabilities, noncurrent in the consolidated balance sheets, each included elsewhere in this prospectus. Changes in the fair value of the contingent consideration are recorded as research and development expenses in the consolidated statement of operations, each included elsewhere in this prospectus.

Accounting Pronouncements Recently Adopted

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Quantitative and Qualitative Disclosures about Market Risk

Market risk represents the risk of loss that may impact our financial position due to adverse changes in financial market prices and interest rates. We are exposed to market risks in the ordinary course of our business. We currently have no outstanding debt or related interest rate risk. Our primary exposure to market risk is related to changes in foreign currency exchange rates, mainly relating to Turnstone Canada. In addition, we contract with certain vendors that are located in Europe and Australia, and the payments under such contracts are denominated in foreign currencies. We are subject to fluctuations in foreign currency rates in connection with these agreements. We do not currently hedge our foreign currency exchange rate risk. As of December 31, 2022 and March 31, 2023, our liabilities denominated in foreign currencies were not material. Accordingly, we do not believe a 10% increase or decrease in current exchange rates would have a material effect on our financial results.

Emerging Growth Company and Smaller Reporting Company Status

The JOBS Act permits an “emerging growth company” such as us to take advantage of reduced reporting requirements that are otherwise applicable to public companies and also an extended transition period to comply with new or revised accounting standards applicable to public companies until those standards would otherwise apply to private companies. We have elected to not “opt out” of this provision and, as a result, we will adopt new or revised accounting standards at the time private companies adopt the new or revised accounting standard and will do so until such time that we either (i) irrevocably elect to “opt out” of such extended transition period or (ii) no longer qualify as an emerging growth company.

We will remain an emerging growth company until the earliest of (i) the last day of the fiscal year following the fifth anniversary of the completion of this offering, (ii) the last day of the fiscal year in which we have total annual gross revenues of $1.235 billion or more, (iii) the date on which we have issued more than $1.0 billion in non-convertible debt during the previous rolling three-year period or (iv) the date on which we are deemed to be a large accelerated filer under the Exchange Act.

We are also a “smaller reporting company” as defined in the Exchange Act. We may continue to be a smaller reporting company even after we are no longer an emerging growth company. We may take advantage of certain of the scaled disclosures available to smaller reporting companies and will be able to take advantage of these scaled disclosures for so long as our ordinary shares held by non-affiliates is less than $250.0 million measured on the last business day of our second fiscal quarter, or our annual revenue is less than $100.0 million during the most recently completed fiscal year and our ordinary shares held by non-affiliates is less than $700.0 million measured on the last business day of our second fiscal quarter.

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BUSINESS

We are a clinical stage biotechnology company focused on developing new medicines to treat and cure patients with solid tumors. Approved immunotherapies represent a significant advancement in the treatment of solid tumors, but many patients either do not respond or experience relapsed disease following an initial response. We believe the most significant challenge to creating curative immunotherapies in these patients is the low numbers of T cells that can recognize and attack the tumor, which we refer to as tumor-reactive T cells. To address this problem, we are pioneering a differentiated approach to tumor infiltrating lymphocytes, or TILs. We are developing next generation TIL therapies by selecting the most potent (meaning able to mediate an anti-tumor response) and tumor-reactive T cells, which we refer to as Selected TILs. Unlike other approaches that rely on standard “bulk TILs” that have demonstrated objective responses in clinical trials only in limited tumor types, we are developing our Selected TILs for potential treatment across the majority of solid tumors. We have initiated two Phase 1 clinical trials for TIDAL-01, including a multi-site trial for the treatment of breast cancer, colorectal cancer, and uveal melanoma, and an investigator sponsored trial with H. Lee Moffitt Cancer Center and Research Institute, Inc., or Moffitt, in both cutaneous and non-cutaneous melanomas. We discuss the nature of this investigator-sponsored trial, including how this trial differs from a clinical trial sponsored by our company, as well as our roles and responsibilities in the trial, in more detail below. We intend to provide an initial clinical update across these two trials in mid-2024. We are also actively advancing our preclinical pipeline programs including TIDAL-02, our next Selected TIL program, and our TIDAL-01 and viral immunotherapy combination program. We define objective response as a patient experiencing a partial response or complete response to any given therapy.

Solid tumors present a major burden to society, with high mortality and poor outcomes associated with more advanced disease. Several key factors, such as tumor heterogeneity (meaning differences in the characteristics, including variable tumor antigen expression, between cancer cells within a patient’s tumor, between tumors within the same patient and/or between different patients’ tumor(s)) and challenging tumor microenvironments, have made treatment of solid tumors more difficult than treatment of hematologic cancers. Immunotherapies that activate the immune system to enhance and/or create anti-tumor immune responses, such as immune checkpoint inhibitors, or ICIs, have improved outcomes for some patients. However, more than 85% of cancer patients fail to respond to ICI therapy. The effectiveness of ICIs is heavily dependent on the presence of tumor-reactive T cells that ICIs can reinvigorate, and many patients lack a sufficient number of T cells that recognize the target tumor. Therefore, we believe new treatments that can expand and enhance the patient’s tumor-reactive T cells are needed.

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including squamous cell carcinoma of the head and neck, cervical cancer, and non-small cell lung cancer. We believe that the activity of TILs is driven by the subset of tumor-reactive T cells, and that the key limitation for bulk TILs is the small number and proportion of tumor-reactive T cells that make up the bulk TIL product (reported median less than 3%, Lowery et al., 2022). We believe increasing the proportion and diversity of tumor-reactive T cells in a TIL product can expand the potential utility of TILs, if approved, to a greater breadth of tumor types, where bulk TILs have shown limited to no objective responses in clinical trials to date.

Our Solution: Selected TILs

We are developing next generation TIL therapies for the potential treatment of multiple solid tumors. There are no TIL therapies that have received FDA approval to date. To our knowledge, at present there are no therapies in clinical development that provide curative outcomes for the majority of patients in our chosen solid tumor indications. Our innovative Selected TIL approach focuses on selecting and expanding the most potent tumor-reactive T cells to overcome the limitations of bulk TILs. This approach expands upon work conducted in academia that demonstrated improved clinical responses for certain selected TILs in solid-tumor types where bulk TILs have shown limited to no objective responses in clinical trials to date. We are leveraging this work to establish a standardized manufacturing process for large scale production of our Selected TILs.

Our Selected TIL approach employs the following foundational principles with the goal of yielding the greatest number and proportion of tumor-reactive T cells in our TIL product candidates:

(1)

(2)

(3)

Expansion of tumor-reactive T cells and removal of non-tumor-reactive bystander cells: We expand our selected tumor-reactive TIL population to magnitudes consistent with bulk TIL products and actively remove unnecessary bystander cells. This selective expansion resulted in a substantially higher proportion of tumor-reactive T cells in the final product in comparison to the relatively infrequent tumor-reactive T cells that are routinely found in bulk TIL. Based on our non-clinical studies across multiple tumor samples to date, we have been able to achieve tumor-reactive T cell frequencies in our Selected TIL drug product of up to 62%, with a median frequency of 23%. With ongoing continuous process improvements as part of our manufacturing strategy we are targeting >70% tumor-reactive T cells in our drug product as we advance clinical development.

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The potential advantages of Selected TILs over bulk TILs are depicted in the figure below.

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Supporting Clinical Evidence

We believe the growing body of prospective and translational clinical data in the TIL field supports the potential of our Selected TIL approach. Third party studies have demonstrated that the anti-tumor activity of bulk TILs is driven by a small subset of tumor-reactive T cells in the bulk TIL product. Furthermore, clinical studies in academic centers utilizing rudimentary selection strategies for tumor-reactive T cells have reported responses including tumor regressions in a single patient bile duct study (Tran et. al., 2014) and a single patient colorectal cancer study (Tran et. al., 2016), one complete response and two partial responses out of six patients in a breast cancer study (Zacharachis, et.al 2022), and two complete responses and one partial response out of seven patients who received a TIL product with confirmed tumor reactivity, in a non-small cell lung cancer study (Creelan et. al., 2021). We define partial response as a patient experiencing a reduction in tumor size or volume as defined by the applicable standard, e.g. response evaluation criteria in solid tumors or RECIST, and no new lesions. A partial response does not indicate that a patient is cured of their disease.

Building a Product Pipeline to Further Enhance the Quality and Function of Selected TILs

Our Selected TIL approach sets us apart from others in the industry that are utilizing bulk TILs, including newer bulk TIL approaches that introduce genetic modifications and culture media additives to enhance TIL quality and function. We believe that without the optimal starting population of tumor-reactive T cells, further enhancements or modifications to bulk TILs are unlikely to succeed in extending their potential utility beyond the limited tumor types where bulk TILs have already shown objective responses in clinical trials. We are also expanding our product pipeline by making additional modifications to our proprietary Selected TILs and deploying them in differentiated combination strategies to further enhance TIL quality and function.

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Modifications to Enhance TIL Quality

Virus Combinations

We are strongly positioned to combine our Selected TIL products with our proprietary viral immunotherapies utilizing two distinct approaches:

•

viral immunotherapy pre-treatment (prior to TIL extraction): optimize TIL harvest and broaden access to indications that are currently less amenable to generating effective TIL products; and

•

viral immunotherapy post-treatment (following delivery of the TIL product): optimize TIL trafficking and function and further increase the activity of our TIL therapies, if approved.

Our Pipeline

We are applying our Selected TIL approach for the potential treatment of a wide range of solid tumors. We are developing a broad pipeline aimed at improving outcomes for patients, as illustrated in the chart below.

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*	Investigator sponsored trial at Moffitt Cancer Center

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We are advancing TIDAL-01, our lead Selected TIL product candidate, for the treatment of multiple solid tumor indications. TIDAL-01 utilizes an unbiased identification and functional screening process to isolate and selectively expand the greatest breadth of tumor-reactive TILs from the patient’s tumor. Our TIDAL-01 production process is designed to deliver at least 10⁹ cells and targets greater than 70% functional and potent tumor-reactive T cells. We have initiated two Phase 1 clinical trials for TIDAL-01, including a multi-site trial for the treatment of breast cancer, colorectal cancer, and uveal melanoma, and an investigator sponsored trial with Moffitt in both cutaneous and non-cutaneous melanomas. Under our multi-site trial, we control all aspects of our trial including, but not limited to, study protocol development, patient selection and enrollment, regulatory interactions, data release, and manufacturing through our CDMO. Under the investigator sponsored trial, which is fully funded by us, Moffitt is solely responsible for regulatory interactions, trial conduct and manufacture of TIDAL-01 at the Moffitt Cancer Cell Therapy Facility, with input and support from us at Moffitt’s discretion. Investigators at Moffitt are also solely responsible for the design of the trial and patient selection and enrollment, where we remain in close contact with the investigators to provide our input if appropriate. Any data disclosures will be made in collaboration with us and any improvements to the TIDAL-01 manufacturing process are solely at our discretion. We intend to provide an initial clinical update across these two trials in mid-2024.

Our History and Team

We have assembled a team with extensive experience in complex biologics, drug discovery and development, manufacturing, and business and commercial product development.

We are led by our Chief Executive Officer, Sammy Farah, M.B.A, Ph.D., who has 20 years of scientific, business, and executive management experience in the biotechnology industry at Synthetic Genomics, Immune Design, Versant Ventures, and Merck.

Our experienced research and clinical development team brings a strong track record of advancing assets through clinical development and delivering products to the market. Our research organization is led by our Chief Scientific Officer, Stewart Abbot, Ph.D., who brings over 20 years of research and development experience in cell-based and immune-oncology products from Adicet, Fate, Celgene and GE Healthcare. Our clinical development and regulatory organization is led by our interim Chief Medical Officer, Michael Burgess, MBChB, Ph.D., who has more than 20 years of experience building research and development teams and leading strategy and execution of clinical development at SpringWorks Therapeutics, Bristol-Myers Squibb, Roche, and Eli Lilly.

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Our chemistry, manufacturing, and control, or CMC, expertise and strategy is anchored in our in-house technical operations team with deep experience across bioprocess, analytical, and formulation development for complex biologics, with a proven track-record of enabling scalable, robust, and industrialized clinical and commercial manufacturing processes and supply chains. Vijay Chiruvolu, Ph.D., our interim Chief Technology Officer who leads our technical operations organization, holds over 27 years of relevant industry experience in process development, manufacturing, supply chain, and quality at Instil Bio, Kite Pharma/Gilead Sciences, Scios, Avigen, Hoffmann-La Roche, Johnson & Johnson, and Amgen, and was responsible for the manufacturing and process teams that worked towards regulatory approval of two cell therapy products, Yescarta and Tecartus.

We believe that actively exploring and forming the right partnerships to drive innovation and enhance our pipeline is core to our strategy and growth. We have assembled a team with sophisticated business development expertise and capital formation experience to drive deal making and transactional activities. Our Chief Business Officer, Saryah Azmat, brings over 10 years of experience in biopharmaceutical business development, corporate strategy and capital formation at Bristol Myers Squibb and Putnam Associates. Our Chief Legal Officer, P. Joseph Campisi, Jr., Esq., holds over 30 years of experience in mergers and acquisitions, collaborations, and securities offerings and corporate governance at Scorpion, Bristol Myers Squibb, and Pillsbury Winthrop; and Venkat Ramanan, Ph.D., our Chief Financial Officer, holds over 20 years of experience in biopharmaceutical finance and operations at Seagen, Gilead, and Amgen.

Since our inception, we have raised $362.0 million in capital, including approximately $172.0 million from preferred stock financings and $190.0 million in non-dilutive payments from strategic partnerships. We are supported by a syndicate that includes entities affiliated with Versant Ventures, OrbiMed Private Investments VI, LP, entities affiliated with F-Prime Capital and entities affiliated with FACIT Inc., or FACIT. Prospective investors should not rely on the investment decisions of our existing investors, as these investors may have different risk tolerances and have received their shares in prior offerings at prices lower than the price offered to the public in this offering. See the section titled “Certain Relationships and Related Party Transactions” for more information.

Our Strategy

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Advance our lead Selected TIL product candidate, TIDAL-01, for the treatment of solid tumors. We are developing TIDAL-01 for the potential treatment of a broad range of solid tumor types and we are pursuing a clinical development strategy designed to demonstrate benefit in multiple indications. We have initiated a Phase 1b clinical trial that will evaluate TIDAL-01 in solid tumors where the benefit of bulk TILs has not been established, including breast cancer, colorectal cancer, and uveal melanoma. Additionally, we have also initiated our investigator sponsored Phase 1 clinical trial in collaboration with Moffitt that will evaluate TIDAL-01 in multiple types of melanoma including cutaneous melanomas, an indication where bulk TILs have shown objective responses in clinical trials. We are very early in our development efforts, and as we make progress, if we obtain positive results of sufficient magnitude from one or both trials, we intend to discuss, receive guidance and the appropriate acceptance from the relevant regulatory agency(ies) to determine if we will be advancing TIDAL-01 into pivotal trials, which are trials that are intended to secure regulatory approval for a product candidate.

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Develop TIDAL-02 and continue to build our pipeline of additional Selected TIL programs. We are expanding our portfolio by making modifications to our Selected TILs to streamline manufacturing and further enhance the quality and function of Selected TILs. This strategy is exemplified by our second Selected TIL program, TIDAL-02. This program is intended to employ a next generation rapid selection process, culture enhancements to improve and maintain TIL quality

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ex vivo, and/or functional gene edits to ensure durable enhancements to TIL quality and persistence in vivo, while minimizing dependance on exogenous IL-2 for in vivo proliferation. We intend to advance TIDAL-02 towards the clinic for the treatment of solid tumor indications that are distinct from and complementary to TIDAL-01, with the goal of moving into earlier lines of therapy. In addition to TIDAL-02, we have ongoing research efforts to further expand our pipeline of Selected TIL programs.

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Leverage viral immunotherapies to further increase the activity of Selected TILs, if approved, across multiple solid tumors. Given our oncolytic virus expertise and our proprietary viral immunotherapies, we believe we are strongly positioned to be a leading company in using viral immunotherapy to further increase the activity of our TIL therapies, if approved. We plan to advance our TIDAL-01 and viral immunotherapy combination strategy to further expand the breadth and depth of response of our Selected TILs across multiple solid tumors. We also plan to explore additional Selected TIL and viral immunotherapy combinations.

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Commercialize and improve patient access to Selected TIL therapy through our CMC development expertise and manufacturing capabilities. We are expanding our in-house cell therapy process and analytical development capacity and capability, and in parallel assembling a network of external manufacturing and supply chain partners. We have designed a robust analytical characterization program to complement clinical development, support regulatory requirements and enable access to our Selected TILs for a broad range of patients with solid tumors. Our intent is that all early-clinical stage Selected TIL product candidates are built upon a CMC foundation with clear line-of-sight to commercial viability, sequenced and staged appropriately with clinical progress.

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Support existing and opportunistically explore future strategic partnerships and collaborations to maximize the potential of our programs. We are leveraging relationships with three academic collaborators, including a strategic partnership with Moffitt, and collaborations with the National Cancer Institute, or NCI, and Centre hospitalier de l’Université de Montreal, or CHUM, to help support development of our Selected TIL approach and pipeline. Our academic relationships are designed to enable us to tap into the deep expertise within these leading institutes that have decades of research and clinical experience in developing TIL therapies. We plan to continue to explore opportunistic collaborations with both academic and industry partners to extend our reach and maximize the potential of our programs.

Background on Solid Tumors and TILs

Solid Tumors: A Medical Need in Cancer

Solid tumors contribute a massive burden to society, with high mortality and poor outcomes associated with more advanced disease. In the United States, there are over 1.6 million new solid tumor cases per year, representing approximately 90% of all cancers. Furthermore, solid tumors result in over 500,000 U.S. deaths per year. Several key factors such as tumor heterogeneity, as well as challenging tumor microenvironments, have made solid tumors very difficult to treat. Despite advances in the oncology treatment landscape, solid tumors continue to result in low rates of long-term survival in the United States. When tumors become refractory to early lines of treatment, options for further therapy are currently limited to alternate forms of chemotherapy, clinical trials of agents in development or palliative care. Each of these alternatives presents a low likelihood of cure, while generally exposing patients to safety and tolerability concerns. Once the cancer metastasizes, mortality exceeds 90%.

Overview of Current Cancer Immunotherapies and Limitations

Immuno-oncology is an evolving field of cancer therapy that is designed to harness the power of the body’s own immune system to prevent, control, and eliminate cancer. Immuno-oncology therapies activate the

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immune system to enhance and/or create anti-cancer immune responses, as well as to overcome immunosuppressive mechanisms that cancer cells have developed. FDA approval of several immunotherapies has firmly established the role of this modality in the fight against cancer. A few of the leading immunotherapies include ICIs and adoptive cell therapy, or ACT.

Immune Checkpoint Inhibitors

The development of ICIs represented a breakthrough for the treatment of various cancers. Immune checkpoints act as gatekeepers of immune responses, down-regulating T cell activity to prevent the destruction of healthy cells. However, cancer cells can also express these checkpoints to evade the immune system. Immune checkpoints have become the focus of numerous therapies that seek to block the activation of inhibitory immunoreceptors and reinvigorate antitumor function of immune cells. Monoclonal antibodies targeting immune checkpoints such as CTLA-4, PD-(L)1, and LAG-3 can restore antitumor immunity, thus reversing immune evasion and promoting tumor cell death. These therapies have found robust commercial success, with approximately $40.0 billion in worldwide sales in 2022. However, they have only incrementally improved broader patient outcomes, with less than 15% of all cancer patients responding to ICI therapy. The effectiveness of ICIs is heavily dependent on the presence of tumor-reactive T cells for this treatment to reinvigorate, and many patients lack enough T cells that recognize the target tumor. Furthermore, ICIs can promote systemic activation of self-reactive T cells resulting in immune-related adverse events.

Adoptive Cell Therapies

ACTs are immunotherapies that directly harness immune cells as the therapeutic modality. These immune cells, often T cells, are isolated from the patient or healthy donors, expanded, and sometimes engineered ex vivo, and then transferred into the patient. These processes allow for the expansion of T cells away from the immunosuppressive nature of the tumor microenvironment. While checkpoint inhibitors seek to re-activate the endogenous immune response, ACTs introduce immune cells into the body to attack target cancer cells. Most of the activity in ACTs has focused on ways to provide the requisite specificity of the T cells to cancer: identifying tumor-associated targets, evaluating their frequency on cancers versus healthy tissues, and evaluating the best ways to traffic T cells to them and attack the cancer. Three of the key ACT modalities utilizing T cells, that have been evaluated for the treatment of cancer include CAR-T, TCR-T, and TILs.

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CAR-T: CAR-T therapies are T cells extracted from blood that have been genetically engineered to express artificial cell surface receptors known as chimeric antigen receptors, or CARs. CARs are comprised of an extracellular binding domain specific to a surface molecule on tumor cells and an intracellular activation domain that turns the T cells “on” to kill tumor cells when the CAR binds to the tumor cell target. While patient-derived, or autologous, CAR-T therapies have been approved and have demonstrated responses in hematological cancers, they have resulted in significant off-tumor effects and limited to no objective responses in clinical trials in solid tumors. CAR-T therapies face a number of challenges in solid tumor settings, including lack of cell surface molecules that can be safely targeted, an inability to recognize intracellular tumor-specific proteins, and tumor antigen heterogeneity. Furthermore, the potent immune activation responsible for the success of CAR-Ts also drives the potential for life-threatening toxicity of cytokine release syndrome.

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TCR-T: TCR-T therapies are T cells extracted from blood that have been genetically engineered to express T cell receptors, or TCRs, that bind specific fragments of proteins presented by the human leukocyte antigen, or HLA, complexes on the surface of target cells. TCR-T therapies are engineered with a cloned TCR that directs the T cells to recognize peptides that arise from the tumor’s mutated proteins or an aberrant or overexpressed self-protein. Unlike CAR-T therapies, TCR-T therapies have the potential to target intracellular proteins preferentially expressed by cancer cells. While there has been some limited clinical success in solid tumors, the HLA-dependent mechanism of TCR-Ts requires careful tissue matching between the transgenic

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TCR and the patient or the expression of engineered TCRs in the patient’s own cells, thus restricting the addressable patient population. In addition, the targeted antigen may not be expressed uniformly across the tumor cells, and this heterogeneity can lead to ineffective targeting of the tumor, tumor escape and treatment-resistant tumor growth.

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TILs: TIL therapies are a type of ACT whereby lymphocytes including T cells are extracted from the patient’s tumor, expanded outside the body, and then infused back into the patient. TILs contain T cells with a diverse set of TCRs and are polyclonal, meaning they recognize multiple different antigens, and polyfunctional, meaning that they have multiple effector functions. Due to these features, TILs have the potential to penetrate tumors and recognize and kill cancer cells and offer potential as a therapeutic for the treatment of solid tumors. To date, TILs have shown objective responses in clinical trials in solid tumors.

We believe that TILs have the potential to address the challenges of solid tumor recognition and heterogeneity in ways that CAR-Ts and TCR-Ts cannot, as illustrated in the figure below.

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Responses Observed with Bulk TILs in Clinical Trials

Patient-specific TIL-based investigational therapies have been studied and developed for the treatment of solid tumors for over three decades. Pioneering work led by Dr. Steven A. Rosenberg, M.D., Ph.D., at NCI, first demonstrated objective responses in clinical trials of TILs in the treatment of melanoma. Most of the early work in TILs was focused on the development of an ACT using “bulk TILs,” whereby all TILs extracted from a patient’s tumor are isolated, expanded ex vivo and then reinfused into the patient.

Over the years, several hundred patients in the United States have received bulk TIL therapies across academia and industry sponsored clinical studies. In metastatic melanoma patients refractory to PD-(L)1 treatments, bulk TIL monotherapy has yielded objective response rates, or ORR, of approximately 30% to 50%, with complete response rates, or CRs, ranging from approximately 5% up to 20%. If a complete response lasts the lifespan of a patient it would be considered as a cure – in general clinical practice patients are referred to as “cured” if they remain in complete response for greater than five years as the probability of their disease recurrence is low. Beyond metastatic melanoma, bulk TIL therapy has demonstrated early therapeutic potential in a limited number of solid tumors including squamous cell carcinoma of the head and neck, cervical cancer, and non-small cell lung cancer. To date, clinical trials of bulk TIL products have trended toward achieving their greatest success in cancers with a high number of mutations, also typically referred to as high tumor mutational burden, or TMB.

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Limitations of Bulk TILs

The body of data spanning decades of research and clinical development in TILs has shed light on what we believe is the key feature that has made TILs successful to date, and also what has limited the success of bulk TILs to a subset of high TMB solid tumor indications. The therapeutic potential in any TIL product is driven by the “tumor-reactive T cells” that are characterized by recognition of tumor-specific antigens. Tumor-reactive T cells are polyclonal and polyfunctional populations of cells that can comprehensively recognize and kill a diverse population of heterogenous tumor cells unique to each patient.

We believe the key limitation of bulk TILs is the small subset of tumor-reactive T cells that exist in most bulk TIL products. Bulk TILs are routinely dosed at 10⁹ cells or more, with tumor-reactive T cells representing reported median values of less than 3% (Lowery et al., 2022) of the total number of cells infused back into the patient. The tumor-reactive T cells included in bulk TIL products may be sufficient to drive utility in some patients with high TMB tumors. However, the fewer the number of mutations in the initial tumor material used to generate the bulk TIL product, the lower the number and proportion of tumor-reactive T cells included in a bulk TIL product, and consequently the lower the activity observed. In fact, across more than 50 patients with epithelial malignancies and low TMB tumors studied at the National Cancer Institute, or NCI, bulk TILs have demonstrated limited to no objective responses in clinical trials.

We believe the limitations described above highlight the need for the next generation of TIL therapy to selectively expand the necessary population of tumor-reactive T cells to maximize the benefit of TILs across a greater breadth of solid tumors. We believe that a greater population of tumor-reactive T cells delivered to a patient in a TIL product can to expand the potential utility of TILs, if approved, to multiple solid tumor types.

Our Solution: Selected TILs

We are developing next generation TIL therapies for the potential treatment of multiple solid tumors. There are no TIL therapies that have received FDA approval to date and at present, no therapies in clinical development for our chosen solid tumor indications have demonstrated consistent curative outcomes for patients. Our innovative Selected TIL approach focuses on selecting and expanding the most potent tumor-reactive T cells to overcome the limitations of bulk TILs. This approach is grounded in work conducted in academia that has demonstrated improved clinical responses for selected TILs in solid tumor types where bulk TILs have not shown objective responses in clinical trials. We are leveraging this work to establish a standardized manufacturing process for large scale production of our Selected TILs.

We are developing Selected TILs based on foundational principles with the goal of yielding the greatest number and proportion of tumor-reactive T cells in our TIL product candidates. We are developing TIL therapies for the potential treatment of a broad range of solid tumor types by employing the following principles:

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Unbiased identification of patient-specific tumor antigens: We seek to identify the most comprehensive set of patient-specific tumor antigens. We use an unbiased identification process that aims to find and capture the greatest diversity of antigens with the potential to drive the most robust T cell response, unlike other TIL products that are biased toward a specific subset or class of antigen(s), which may miss relevant tumor antigens or focus on the wrong targets.

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Selection of greatest breadth of tumor-reactive T cells from patient extracted TILs: Our goal is to capture and isolate the greatest number and proportion of a patient’s tumor-reactive T cells that have the potential to attack and destroy heterogeneous solid tumors. We aim to select the greatest diversity of T cells, by using a functional-based screening process that confirms reactivity to the identified patient-specific tumor antigens rather than relying on a bioinformatics-based prediction algorithm that may not be truly predictive. Importantly, we seek to select for both CD8+ T cells, which can directly kill tumor cells, and CD4+ T cells, which stimulate and recruit other immune cells to tumor sites; studies have shown that the presence of both types of T cells is important for effective tumor control.

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Expansion of all tumor-reactive T cells and removal of all non-tumor-reactive bystander cells: We expand our selected tumor-reactive TIL population to magnitudes consistent with bulk TIL products and actively remove unnecessary bystander cells. This selective expansion has resulted in a substantially higher proportion of tumor-reactive T cells in the final product in comparison to the relatively infrequent tumor-reactive T cells that are routinely found in bulk TIL. Based on our non-clinical studies across multiple tumor samples to date, we have been able to achieve tumor-reactive T cell frequencies in our selected TIL drug product of up to 62%, with a median frequency of 23%. With ongoing continuous process improvements as part of our manufacturing strategy we are targeting >70% tumor-reactive T cells in our drug product as we advance clinical development.

The potential advantages of Selected TILs over bulk TILs are depicted in the figure below.

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The approach described above is inherently designed to select for and characterize the active TIL produc