10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended March 31, 2024

OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission File Number: 001-39866

eFFECTOR Therapeutics, Inc.

(Exact name of Registrant as specified in its Charter)

Delaware	85-3306396
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
142 North Cedros Avenue, Suite B Solana Beach, CA	92075
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (858) 925-8215

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common stock, $0.0001 par value per share	EFTR	Nasdaq Capital Market
Warrants to purchase common stock	EFTRW	Nasdaq Capital Market

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

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.

Large accelerated filer	☐	Accelerated filer	☐
Non-accelerated filer	☒	Smaller reporting company	☒
Emerging growth company	☒

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 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of April 30, 2024, the registrant had 4,704,409 shares of common stock, $0.0001 par value per share, outstanding.

Table of Contents

		Page
PART I.	FINANCIAL INFORMATION	1
Item 1.	Financial Statements (Unaudited)	1
	Condensed Consolidated Balance Sheets	1
	Condensed Consolidated Statements of Operations and Comprehensive Loss	2
	Condensed Consolidated Statements of Stockholders' Equity (Deficit)	3
	Condensed Consolidated Statements of Cash Flows	4
	Notes to Unaudited Condensed Consolidated Financial Statements	5
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	19
Item 3.	Quantitative and Qualitative Disclosures About Market Risk	27
Item 4.	Controls and Procedures	27
PART II.	OTHER INFORMATION	29
Item 1.	Legal Proceedings	29
Item 1A.	Risk Factors	29
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	29
Item 3.	Defaults Upon Senior Securities	29
Item 4.	Mine Safety Disclosures	29
Item 5.	Other Information	29
Item 6.	Exhibits	30
Signatures		32

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PART I—FINANCIAL INFORMATION

Item 1. Financial Statements.

eFFECTOR THERAPEUTICS, INC.

Condensed Consolidated Balance Sheets

(in thousands, except share and par value data)

(Unaudited)

	March 31, 2024			December 31, 2023
Assets
Current assets:
Cash and cash equivalents	$	15,508		$	14,875
Short-term investments		9,875			3,495
Prepaid expenses and other current assets		867			1,468
Total current assets		26,250			19,838
Property and equipment, net		190			140
Operating lease right-of-use assets		225			53
Other assets		466			513
Total assets	$	27,131		$	20,544
Liabilities and stockholders' equity (deficit)
Current liabilities:
Accounts payable	$	1,713		$	2,330
Accrued expenses		3,787			2,921
Current term loans, net		18,916			19,385
Accrued final payment on term loans, current		1,100			1,100
Lease liabilities, current portion		53			60
Total current liabilities		25,569			25,796
Other accrued liabilities, non-current		516			503
Non-current warrant liability		40			40
Non-current lease liabilities		179			—
Total liabilities		26,304			26,339
Commitments and contingencies
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 100,000,000 shares authorized at March 31, 2024      and December 31, 2023; zero shares issued and outstanding as of      March 31, 2024 and December 31, 2023		—			—
Common stock, $0.0001 par value; 40,000,000 shares authorized at March 31, 2024      and December 31, 2023; 3,914,309 shares issued and 3,902,309 shares issued and      outstanding as of March 31, 2024; 2,994,679 shares issued and 2,982,679 shares      issued and outstanding as of December 31, 2023		—			—
Additional paid-in capital		189,038			173,582
Accumulated other comprehensive income (loss)		—			—
Accumulated deficit		(188,211	)		(179,377	)
Total stockholders' equity (deficit)		827			(5,795	)
Total liabilities and stockholders' equity (deficit)	$	27,131		$	20,544

The accompanying notes are an integral part of these condensed consolidated financial statements.

1

eFFECTOR THERAPEUTICS, INC.

Condensed Consolidated Statements of Operations and Comprehensive Loss

(in thousands, except share and per share data)

(Unaudited)

	Three Months Ended March 31,
	2024			2023
Operating expenses:
Research and development		5,306			6,609
General and administrative		3,090			2,927
Total operating expenses		8,396			9,536
Operating loss		(8,396	)		(9,536	)
Other income (expense)
Interest income		323			226
Interest expense		(749	)		(689	)
Other expense		(12	)		(15	)
Total other income (expense)		(438	)		(478	)
Net loss	$	(8,834	)	$	(10,014	)
Comprehensive loss:
Net loss	$	(8,834	)	$	(10,014	)
Other comprehensive income		—			19
Comprehensive loss	$	(8,834	)	$	(9,995	)
Net loss per share, basic and diluted	$	(2.16	)	$	(5.96	)
Weighted-average common shares outstanding, basic and diluted		4,081,580			1,680,032

The accompanying notes are an integral part of these condensed consolidated financial statements.

2

eFFECTOR THERAPEUTICS, INC.

Condensed Consolidated Statements of Stockholders’ Equity (Deficit)

(in thousands, except share data)

(Unaudited)

							Accumulated
					Additional		Other						Total
	Common Stock				Paid-in		Comprehensive			Accumulated			Stockholders'
	Shares		Amount		Capital		Income			Deficit			Equity (Deficit)
Balance at December 31, 2023		2,982,679	$	—	$	173,582	$	—		$	(179,377	)	$	(5,795	)
Stock option and pre-funded warrant exercises		497,834		—		—		—			—			—
Issuance of common stock, net of issuance costs		421,796		—		14,446		—			—			14,446
Stock-based compensation expense		—		—		1,010		—			—			1,010
Unrealized gain on short-term investments		—		—		—		—			—			—
Net loss		—		—		—		—			(8,834	)		(8,834	)
Balance at March 31, 2024		3,902,309	$	—	$	189,038	$	—		$	(188,211	)	$	827
							Accumulated
					Additional		Other						Total
	Common Stock				Paid-in		Comprehensive			Accumulated			Stockholders'
	Shares		Amount		Capital		Loss			Deficit			Equity (Deficit)
Balance at December 31, 2022		1,667,602	$	—	$	147,480	$	(18	)	$	(143,566	)	$	3,896
Stock option exercises		—		—		—		—			—			—
Issuance of common stock, net of issuance costs		16,433		—		119		—			—			119
Stock-based compensation expense		—		—		1,167		—			—			1,167
Unrealized loss on short-term investments		—		—		—		19			—			19
Net loss		—		—		—		—			(10,014	)		(10,014	)
Balance at March 31, 2023		1,684,035	$	—	$	148,766	$	1		$	(153,580	)	$	(4,813	)

The accompanying notes are an integral part of these condensed consolidated financial statements.

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eFFECTOR THERAPEUTICS, INC.

Condensed Consolidated Statements of Cash Flows

(in thousands)

(Unaudited)

	Three Months Ended March 31,
	2024			2023
Operating activities:
Net loss	$	(8,834	)	$	(10,014	)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization expense		28			28
Accretion of discount and amortization of premium on investments, net		(60	)		(119	)
Stock-based compensation		1,010			1,167
Other expense related to equity purchase agreement		12			15
Non-cash interest expense		87			76
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		267			(180	)
Other non-current assets		53			48
Accounts payable		(716	)		2,225
Accrued expenses		875			(886	)
Operating lease right-of-use assets and liabilities, net		—			3
Net cash used in operating activities		(7,278	)		(7,637	)
Investing activities:
Purchases of fixed assets		—			(13	)
Maturities of short-term investments		3,500			12,000
Purchases of short-term investments		(9,821	)		(2,960	)
Net cash provided by (used in) investing activities		(6,321	)		9,027
Financing activities:
Repayment of term loans		(556	)		—
Proceeds from exercise of common stock options and pre-funded warrants		1			—
Proceeds from issuance of common stock, net of issuance costs		14,787			212
Net cash provided by financing activities		14,232			212
Net increase in cash and cash equivalents		633			1,602
Cash and cash equivalents at beginning of period		14,875			8,708
Cash and cash equivalents at end of period	$	15,508		$	10,310
Supplemental disclosure of cash flow information:
Interest paid	$	655		$	589
Operating lease liabilities arising from obtaining right-of-use assets		186			—
Supplemental disclosure of non-cash investing and financing activities:
Accrued issuance costs	$	109		$	170

The accompanying notes are an integral part of these condensed consolidated financial statements.

4

eFFECTOR THERAPEUTICS, INC.

Notes to Consolidated Financial Statements

(Unaudited)

1. Organization and Basis of Presentation

Description of Business

Locust Walk Acquisition Corp. ("LWAC”) was initially formed on October 2, 2020 as a Delaware corporation formed for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or other similar business transaction with one or more operating businesses.

On May 26, 2021, LWAC entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Locust Walk Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of LWAC (“Merger Sub”), and eFFECTOR Therapeutics, Inc., a Delaware corporation (“ Old eFFECTOR”).

Pursuant to the terms of the Merger Agreement, a business combination between LWAC and Old eFFECTOR was effected through the merger of the Merger Sub with and into Old eFFECTOR, with Old eFFECTOR becoming the surviving company and a wholly-owned subsidiary of LWAC with the name of eFFECTOR Therapeutics Operations, Inc. On August 25, 2021, and in connection with the closing of the business combination (the "Business Combination"), LWAC was renamed eFFECTOR Therapeutics, Inc. ("eFFECTOR" or the "Company"). All outstanding preferred shares of Old eFFECTOR converted into common shares of Old eFFECTOR on a 1:1 basis, which were then converted, along with all outstanding common shares of Old eFFECTOR, into common shares of the surviving eFFECTOR company through application of an exchange ratio of approximately 0.09657.

The Company is a clinical-stage biopharmaceutical company focused on pioneering the development of a new class of oncology drugs the Company refers to as selective translation regulator inhibitors ("STRIs"). The Company’s principal operations are in the United States, with its headquarters in Solana Beach, California. The Company has devoted substantially all of its resources to raising capital, identifying potential product candidates, establishing its intellectual property portfolio, conducting preclinical studies and clinical trials, establishing arrangements with third parties for the manufacture of its product candidates and related raw materials, and providing general and administrative support for these operations. The Company has not generated revenues from its principal operations, other than from licensing and grant revenue, through March 31, 2024.

Reverse Stock Split

On January 9, 2024, the Company filed a Certificate of Amendment to the Company’s Amended and Restated Certificate of Incorporation, as amended to date, with the Secretary of State of the State of Delaware to effect a reverse stock split of the Company’s common stock, par value $0.0001 at a ratio of 1-for-25 (the “Reverse Stock Split”), as authorized at the Company’s 2023 annual meeting of stockholders held on June 22, 2023. The Company effected the Reverse Stock Split on January 12, 2024. No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who otherwise were entitled to a fractional share of common stock were entitled to receive a proportional cash payment. The number of shares of common stock that the Company is authorized to issue was proportionally reduced from 1,000,000,000 shares to 40,000,000 shares and the par value of its common stock remains unchanged at $0.0001 per share.

The Company has retroactively restated the share and per share amounts in the consolidated financial statements as of December 31, 2023 and for the three months ended March 31, 2024 and 2023. Proportionate adjustments were made to the per share exercise price and number of shares of common stock issuable under all outstanding stock options and warrants. In addition, proportionate adjustments have been made to the number of shares of common stock reserved for the Company’s equity incentive compensation plans. The consolidated statements of stockholders’ equity (deficit) and balance sheets reflect the impact of the Reverse Stock Split by reclassifying from “common stock” to “additional paid-in capital” in an amount equal to the par value of the decreased shares resulting from the Reverse Stock Split.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements as of March 31, 2024 and for the three months ended March 31, 2024 and 2023 have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act of 1933, as amended (the “Securities Act”). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. These unaudited financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows. The results for the three months ended March 31, 2024 are not necessarily indicative of the results expected for the full fiscal year or any subsequent interim period. The balance sheet at December 31, 2023 has been derived from the audited financial statements at that date but does not include all the disclosures required by GAAP for complete financial statements. Because all of the disclosures required by GAAP for complete financial

5

statements are not included herein, these unaudited financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2023 included in its Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 26, 2024.

Liquidity

The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of 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 the outcome of this uncertainty.

Management is required to perform a two-step analysis over its ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (step 2).

The Company has experienced net losses and negative cash flows from operating activities since its inception, aside from the years ended December 31, 2021 and December 31, 2020 when net income was realized as a result of a gain in fair value recognized associated with the earn-out liability and revenue in connection with the Research Collaboration and License Agreement with Pfizer, respectively. The Company has an accumulated deficit of $188.2 million at March 31, 2024. For the three months ended March 31, 2024, the Company used $7.3 million in cash for operations. At March 31, 2024, the Company had cash and cash equivalents and short-term investments of $25.4 million. The Company anticipates that its expenses will increase significantly in connection with its ongoing activities to support its research and development efforts, and it expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. Management has prepared cash flow forecasts which indicate that based on the Company’s expected operating losses and negative cash flows, there is substantial doubt about the Company’s ability to continue as a going concern within twelve months from the date that these financial statements for the three months ended March 31, 2024 are issued. The principal payments due under the Oxford Loans (as defined below), and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed above and the assessment that the material adverse change clause under the Oxford Loans is not within the Company’s control. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements.

The Company’s ability to continue as a going concern is dependent upon its ability to receive additional capital. Management intends to raise additional capital through equity offerings or other capital sources, including potential additional collaborations, licenses and other similar arrangements. Additionally, the Company may receive additional milestone payments from the Research Collaboration and License Agreement with Pfizer (described in Note 10), through the issuance of common stock under the equity purchase agreement with Lincoln Park Capital Fund, LLC (described in Note 8) or through the issuance of common stock under the at-the-market offering program (described in Note 8) with Cantor Fitzgerald & Co. However, the Company may not be able to secure additional financing in a timely manner or on favorable terms, if at all, and may not receive any milestone payments. Without additional capital, the Company may be forced to delay, scale back or eliminate some of its research and development activities, or other operations and potentially delay product development in an effort to provide sufficient funds to continue its operations, or may be required to pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of its stockholders.

2.Summary of Significant Accounting Policies

Research and Development Costs

Research and development expenses primarily consist of costs associated with the preclinical and clinical development of the Company’s product candidates. Research and development costs are expensed as incurred.

Clinical Trial Accruals and Preclinical Studies

The Company records expenses resulting from our obligations under contracts with vendors and consultants, CROs and clinical sites in connection with conducting clinical trials and preclinical studies. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects clinical trial and preclinical study expenses in the financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial or preclinical study as measured by the timing of various aspects of the clinical trial, preclinical study, or related activities. The Company determines accrual estimates based on the underlying contracts, correspondence with clinical and other key personnel and third-party service providers as to the progress of the clinical trials, preclinical studies, or other services being conducted, and amounts invoiced or paid to date. During the course of a clinical trial or preclinical study, the Company adjusts the rate of expense recognition if actual results differ from estimates.

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Public and Private Placement Warrants

Upon completion of the Business Combination, the Company assumed public and private placement warrants that were issued by LWAC in connection with their initial public offering in January 2021 whereby holders of the public and private placement warrants are entitled to acquire common stock of the Company. The Company has concluded that the public warrants are equity-classified. Since the settlement value of the private placement warrants is dependent, in part, on who holds the warrants at the time of settlement, they are not considered indexed to the Company's stock and are therefore recorded as liabilities. Warrants classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying consolidated statements of operations and comprehensive income (loss). The Company estimates the fair value of these warrants using the Black-Scholes option pricing model.

Stock-Based Compensation Expense

Stock-based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model. The Company accounts for stock options granted to non-employees using the fair value approach.

The Black-Scholes option-pricing model requires the use of subjective assumptions, including the risk-free interest rate, the expected stock price volatility, the expected term of stock options, and the expected dividend yield. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The fair value of the underlying common stock used within the Black-Scholes option-pricing model is based on the closing price of common stock on the date of grant.

Comprehensive Loss

Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company presents comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss.

Cash, Cash Equivalents and Short-term Investments

Cash and Cash Equivalents

The Company considers all highly liquid investments with insignificant interest rate risk and an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase.

Short-term Investments

Short-term investments consist of U.S. Treasury securities, classified as available-for-sale securities and have maturities of greater than three months but less than one year. The Company has classified all of its available-for-sale securities as current assets on the balance sheets because these are considered highly liquid securities and are available for use in current operations. The Company carries these securities at fair value and reports unrealized gains and losses as a separate component of accumulated other comprehensive loss. Amortization and accretion of any purchase premiums or discounts is included in interest income in the consolidated statements of operations and comprehensive loss.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes, based on its preliminary assessment, that the impact of recently issued standards that are not yet effective will not have a material impact on their financial position or results of operations upon adoption.

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as

7

they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position.

For the three months ended March 31, 2024, all pre-funded warrants that were issued during the January 2024 Registered Direct Offering (as defined below) with an exercise price of $0.001, regardless of whether they were exercised as of March 31, 2024, were considered outstanding in the calculation of basic and diluted net loss per share (See Note 7 for details about pre-funded warrants).

Potentially dilutive securities as of March 31, 2024 and 2023 are as follows (in common stock equivalent shares):

	For the Three Months Ended March 31,
	2024		2023
Common stock warrants		2,257,426		—
Placement agent warrants		158,017		—
Public warrants		233,332		233,332
Private placement warrants		7,266		7,266
Earn-Out Shares		—		200,000
Unvested sponsor shares		12,000		12,000
Stock options outstanding		694,764		473,900
Total		3,362,805		926,498

3. Fair Value Measurements

The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

Level 2: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability.

Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e. supported by little or no market activity).

The Company’s cash equivalents are classified using Level 1 inputs within the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented.

The Company estimates the fair value of its warrant liabilities at the time of issuance and subsequent remeasurement using the Black-Scholes option pricing model at each reporting date, if required, based on the following inputs: the risk-free interest rates; the expected dividend rates; the remaining contractual life of the warrants; the fair value of the underlying stock; and the expected volatility of the price of the underlying stock. The estimates are based, in part, on subjective assumptions and could differ materially in the future. Changes to these assumptions as well as the fair value of the Company’s stock on the reporting date can have a significant impact on the fair value of the warrant liability.

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The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy as of March 31, 2024 and December 31, 2023 (in thousands):

			Fair Value Measurements Using
	March 31,		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	2024		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	6,048	$	6,048	$	—	$	—
U.S. Treasury securities		9,460		—		9,460		—
Short-term investments:
U.S. Treasury securities		9,875		—		9,875		—
Total assets	$	25,383	$	6,048	$	19,335	$	—
Liabilities
Private placement warrant liability	$	40	$	—	$	—	$	40
Total liabilities	$	40	$	—	$	—	$	40

			Fair Value Measurements Using
	December 31,		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	2023		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	10,887	$	10,887	$	—	$	—
U.S. Treasury securities		3,988		—		3,988		—
Short-term investments:
U.S. Treasury securities		3,495		—		3,495		—
Total assets	$	18,370	$	10,887	$	7,483	$	—
Liabilities
Private placement warrant liability	$	40	$	—	$	—	$	40
Total liabilities	$	40	$	—	$	—	$	40

Cash Equivalents and Short-Term Investments

Financial assets measured at fair value on a recurring basis consist of the Company’s cash equivalents and short-term investments. Cash equivalents consisted of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase and short-term investments consisted of U.S. Treasury securities with an original maturity of more than three months at the date of purchase. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, and bids and/or offers.

Investments are classified as Level 1 within the fair value hierarchy if their quoted prices are available in active markets for identical securities. Investments in money market funds of $6.0 million and $10.9 million as of March 31, 2024 and December 31, 2023, respectively, were classified as Level 1 instruments and were included in cash and cash equivalents.

Investments in marketable securities are valued using Level 2 inputs. Level 2 securities are initially valued at the transaction price and subsequently valued and reported upon utilizing inputs other than quoted prices that are observable either directly or indirectly, such as quotes from third-party pricing vendors. Fair values determined by Level 2 inputs, which utilize data points that are observable such as quoted prices, interest rates and yield curves, require the exercise of judgment and use of estimates, that if changed, could significantly affect the Company’s financial position and results of operations. The marketable securities of $19.3 million as of March 31, 2024 were classified as Level 2 instruments, $9.5 million of which is included in cash and cash equivalents and $9.9 million of which is included in short-term investments. The marketable securities of $7.5 million as of December 31, 2023 were classified as Level 2 instruments, $4.0 million of which is included in cash and cash equivalents and $3.5 million of which is included in short-term investments. Accrued interest receivable related to short-term investments was $17,000 and $52,000 as of March 31, 2024 and December 31, 2023, respectively, and included as part of prepaid expenses and other current assets in the condensed balance sheets.

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The following tables summarize the Company’s short-term investments accounted for as available-for-sale securities as of March 31, 2024 and December 31, 2023 (in thousands):

				March 31, 2024
	Maturity	Amortized		Unrealized		Unrealized		Estimated
	(in years)	Cost		Gains		Losses		Fair Value
U.S. Treasury securities	1 year or less	$	9,875	$	—	$	—	$	9,875
		$	9,875	$	—	$	—	$	9,875

				December 31, 2023
	Maturity	Amortized		Unrealized		Unrealized		Estimated
	(in years)	Cost		Gains		Losses		Fair Value
U.S. Treasury securities	1 year or less	$	3,495	$	—	$	—	$	3,495
		$	3,495	$	—	$	—	$	3,495

Private Placement Warrant Liability

In connection with the Business Combination, the Company assumed the public and private placement warrants described in Note 2. The private placement warrants are precluded from equity treatment and are recorded as liabilities as they are not considered indexed to the Company's common stock. The private placement warrant liability is measured at fair value, using a combination of observable and unobservable inputs. The change in fair value of the private placement warrant liability is recorded in other income (expense) on the statement of operations and comprehensive loss. The following key assumptions were used in determining the fair value of the private placement warrant liability valued using the Black-Scholes option pricing model as of March 31, 2024 and December 31, 2023:

	March 31, 2024			December 31, 2023
Common stock price	$	14.39		$	11.69
Expected volatility		125.0	%		125.0	%
Risk-free interest rate		4.5	%		4.1	%
Expected term (in years)		2.4			2.7
Expected dividend yield		—			—

The following table presents activity for the private placement warrant liability measured at fair value using significant unobservable Level 3 inputs during the three months ended March 31, 2024 (in thousands):

	Private Placement Warrant Liability
Balance at December 31, 2023	$	40
Change in fair value		—
Balance at March 31, 2024	$	40

4. Property and Equipment, net

Property and equipment, net consists of the following (in thousands):

	March 31, 2024			December 31, 2023
Lab equipment	$	108		$	30
Computer and office equipment		154			154
Furniture and fixtures		78			78
Leasehold improvements		188			188
Construction in process		14			14
		542			464
Less accumulated depreciation and amortization		(352	)		(324	)
	$	190		$	140

The Company recorded depreciation and amortization expense of approximately $28,000 for each of the three months ended March 31, 2024 and 2023.

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5. Accrued Expenses

Accrued expenses consist of the following (in thousands):

	March 31, 2024		December 31, 2023
Employee compensation	$	978	$	1,587
Research and development		2,461		1,036
Professional and outside services		131		75
Interest		217		223
	$	3,787	$	2,921

6. Term Loans

Oxford Term Loans

In March 2021, Old eFFECTOR entered into a Loan and Security Agreement (“Oxford LSA”) with Oxford Finance LLC (“Oxford”), pursuant to which the Company may borrow up to $30.0 million, issuable in two separate tranches of $20.0 million (“Term A Loans”) and $10.0 million (“Term B Loans”), collectively referred to as the Oxford Loans. In March 2021, the Company borrowed $20.0 million of the Term A Loans. The Company is required to make a final payment equal to 5.5% of the Term A Loans at maturity, which has been recorded as a debt discount for the Term A Loans and is being amortized over the term of the debt arrangements. In connection with the Oxford LSA, the Company issued warrants to purchase a total of 1,503 shares of Series C Preferred Stock at an exercise price of $133.25 per share.

On February 22, 2022, the Company entered into an amendment to the Oxford LSA whereby the interest only period for the Term A Loans ended on March 1, 2024. In connection with the amendment, the maturity of the Term A Loans was extended from March 18, 2026 to February 1, 2027. Additionally, Term B Loans would have become available to the Company after January 1, 2023 upon achievement of certain clinical development milestones, until the earlier of (i) June 30, 2023, (ii) 45 days after the achievement of certain clinical development milestones, and (iii) the occurrence of an event of default. As the Company did not achieve the clinical development milestones by June 30, 2023, it no longer has access to the additional $10.0 million under the Term B Loans. The amendment was accounted for as a debt modification as the modified debt was not substantially different from the original debt and the cash flows were not significantly changed.

The Oxford Loans carry a variable interest rate equal to the greater of (i) 7.7% and (ii) the sum of the prime rate plus 4.45%. The Company has the option to prepay all, but not less than all, of the borrowed amounts, and there is no prepayment fee for a prepayment made after the third anniversary of the effective date of the Oxford LSA and prior to the maturity date.

The Company’s obligations under the Oxford LSA are secured by a first priority security interest in substantially all of its current and future assets, other than its owned intellectual property. The Company is also obligated to comply with various other customary covenants, including restrictions on its ability to encumber intellectual property assets without consent.

The Company recorded a debt discount of $1.6 million for the estimated fair value of warrants, debt issuance costs, and final payment to be made, which is being amortized to interest expense over the term of the loan using the effective-interest method. As of March 31, 2024, the Company had $19.4 million of outstanding principal under the Term A Loans of which $18.9 million is reflected on the balance sheet net of debt discounts. As of December 31, 2023, the Company had $20.0 million of outstanding principal under the Term A Loans of which $19.4 million is reflected on the balance sheet net of debt discounts. Interest expense, including amortization of debt discount related to the Oxford Term A Loans, totaled $0.7 million for each of the three months ended March 31, 2024 and 2023. The Company is in compliance with all covenants under the Oxford LSA as of March 31, 2024. The Term A Loans include customary events of default, including instances of a material adverse change in our operations, that may require prepayment of the outstanding Term A Loans. The principal payments due under the Oxford Loans, and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed in the Liquidity section of Note 1. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements.

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Based on the outstanding principal amounts for the Company’s Term A Loans, the following table sets forth by year the Company’s required future principal payments as of March 31, 2024 (in thousands):

As of March 31, 2024
Remainder of 2024	$	5,000
2025		6,667
2026		6,667
2027		1,110
Required future principal payments	$	19,444
Unamortized debt discount		(528	)
Current term loans, net as of March 31, 2024	$	18,916

7. Warrants

Assumed Public Warrants and Private Placement Warrants

Following the consummation of the Business Combination, holders of the public warrants and private placement warrants are entitled to acquire common stock of the Company. The warrants became exercisable on January 12, 2022, which is 12 months from the closing of the LWAC's initial public offering. Each warrant entitles the registered holder to purchase one share of common stock at an exercise price of $287.50 per share. The public warrants and private placement warrants will expire on August 25, 2026, which is five years after the completion of the Business Combination.

Once the public warrants and private placement warrants became exercisable, the Company has the right to redeem the outstanding warrants in whole and not in part at a price of $0.25 per warrant upon a minimum of 30 days’ prior written notice of redemption, if and only if the last sale price of the common stock equals or exceeds $450.00 per share for any 20 trading days within a 30-trading day period ending on the third trading day prior to the date on which the Company sends the notice of redemption to the warrant holders.

The private placement warrants are identical to the public warrants except that, so long as they are held by the sponsor or its permitted transferees: (i) they will not be redeemable by the Company; (ii) they may be exercised by the holders on a cashless basis; and (iii) they are subject to registration rights.

Private placement warrants are liability-classified (See Note 3) and the public warrants are equity-classified. The following table summarizes the number of outstanding public warrants and private placement warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023		Exercise Price		Expiration Date
Public warrants		233,332		233,332	$	287.50	August 24, 2026
Private placement warrants		7,266		7,266	$	287.50	August 24, 2026

Warrants - Registered Direct Offerings

In May 2023, the Company completed a registered direct offering (“May 2023 Registered Direct Offering”) which included the issuance of 270,015 shares of common stock in the form of pre-funded warrants with a purchase price of $16.35 per share and an exercise price of $0.025 (the “May 2023 Pre-Funded Warrants”). The May 2023 Pre-Funded Warrants were immediately exercised. Additionally, in a concurrent private placement, the Company issued warrants to purchase up to 458,015 shares of common stock (the “May 2023 Common Stock Warrants”) with an exercise price of $13.25 per share. The May 2023 Common Stock Warrants will expire on November 30, 2028, which is five and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 32,060 shares of common stock ("May 2023 Placement Agent Warrants") with an exercise price of $20.47 per share. The May 2023 Placement Agent Warrants will expire on May 26, 2028, which is five years following the commencement of sales in the May 2023 Registered Direct Offering. See Note 8 for additional detail surrounding the May 2023 Registered Direct Offering.

In June 2023, the Company completed a registered direct offering (“June 2023 Registered Direct Offering”) which included the issuance of 72,578 shares of common stock in the form of pre-funded warrants with a purchase price of $28.10 per share and an exercise price of $0.025 (the “June 2023 Pre-Funded Warrants”). The June 2023 Pre-Funded Warrants were immediately exercised. Additionally, in a concurrent private placement, the Company issued warrants to purchase up to 310,577 shares of common stock (the “June 2023 Common Stock Warrants”) with an exercise price of $25.00 per share. The June 2023 Common Stock Warrants will expire on December 8, 2028, which is five and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 21,739 shares of common stock ("June 2023 Placement Agent Warrants") with an exercise price of $35.1575 per share. The June 2023 Placement Agent Warrants will expire on June 6, 2028, which is five years

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following the commencement of sales in the June 2023 Registered Direct Offering. See Note 8 for additional detail surrounding the June 2023 Registered Direct Offering.

In January 2024, the Company completed a registered direct offering (“January 2024 Registered Direct Offering”) which included the issuance of 1,150,834 shares of common stock in the form of pre-funded warrants with a purchase price of $10.074 per share and an exercise price of $0.001 (the “January 2024 Pre-Funded Warrants”), of which 497,834 were exercised as of March 31, 2024. Additionally, the Company concurrently issued warrants to purchase up to 1,488,834 shares of common stock (the “January 2024 Common Stock Warrants”) with an exercise price of $9.95 per share. The January 2024 Common Stock Warrants will expire on July 29, 2027, which is three and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 104,218 shares of common stock ("January 2024 Placement Agent Warrants") with an exercise price of $12.5938 per share. The January 2024 Placement Agent Warrants will expire on July 29, 2027, which is three and one-half years from the issuance date. See Note 8 for additional detail surrounding the January 2024 Registered Direct Offering.

The common stock warrants, placement agent warrants and pre-funded warrants are equity-classified. The following table summarizes the number of outstanding common stock warrants, placement agent warrants and pre-funded warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023		Exercise Price		Expiration Date
May 2023 Common Stock Warrants		458,015		458,015	$	13.25	November 30, 2028
May 2023 Placement Agent Warrants		32,060		32,060	$	20.47	May 26, 2028
June 2023 Common Stock Warrants		310,577		310,577	$	25.00	December 8, 2028
June 2023 Placement Agent Warrants		21,739		21,739	$	35.1575	June 6, 2028
January 2024 Pre-funded Warrants		653,000		—	$	0.001	N/A
January 2024 Common Stock Warrants		1,488,834		—	$	9.95	July 29, 2027
January 2024 Placement Agent Warrants		104,218		—	$	12.5938	July 29, 2027

8. Preferred Stock and Stockholders’ Equity (Deficit)

Purchase Agreement

On January 24, 2022, the Company entered into an equity purchase agreement (the “Purchase Agreement”) and a registration rights agreement with Lincoln Park Capital Fund, LLC (“Lincoln Park”) which provides for the sale to Lincoln Park up to $50.0 million of shares (the “Purchase Shares”) of the Company's common stock over the thirty-six (36) month term of the Purchase Agreement. In connection with the Purchase Agreement, Lincoln Park made an initial purchase of $3.0 million of shares of common stock, which equated to 22,304 shares of common stock, and the Company issued 5,717 shares of common stock to Lincoln Park as a commitment fee in connection with entering into the Purchase Agreement. The Company recognized $0.8 million of other expense relating to the commitment fee share issuance. As of March 31, 2024, a total of 1,200 shares of common stock have been sold in addition to the upfront amount, with such shares sold during the three months ended June 30, 2022. There were no purchases under the Purchase Agreement during the three months ended March 31, 2024 and 2023.

Under the Purchase Agreement, the Company has sole discretion, subject to certain conditions, on any business day selected by the Company to require Lincoln Park to purchase up to 1,200 shares of common stock (the “Fully Adjusted Regular Purchase Share Limit”) at the Purchase Price (as defined below) per purchase notice (each such purchase, a “Regular Purchase”). The Fully Adjusted Regular Purchase Share Limit may be increased as follows: to up to 2,000 shares if the closing price is not below $125.00, and up to 3,000 shares if the closing price is not below $250.00. Lincoln Park’s committed obligation under each Regular Purchase is capped at $500,000, unless the Parties agree otherwise. The purchase price for Regular Purchases (the “Purchase Price”) shall be equal to the lesser of: (i) the lowest sale price of the common shares during the Purchase Date (as defined in the Purchase Agreement), or (ii) the average of the three (3) lowest closing sale prices of the common shares during the ten (10) business days prior to the Purchase Date.

In addition to Regular Purchases and subject to certain conditions and limitations, the Company in its sole discretion may require Lincoln Park on each Purchase Date to purchase on the following business day up to the lesser of (i) three (3) times the number of shares purchased pursuant to such Regular Purchase or (ii) 25% of the trading volume on the Accelerated Purchase Date (as defined in the Purchase Agreement) (the “Accelerated Purchase”) (unless the Parties agree otherwise) at a purchase price equal to the lesser of 97% of (i) the closing sale price on the Accelerated Purchase Date, or (ii) the Accelerated Purchase Date’s volume weighted average price (the “Accelerated Purchase Price”). The Company has the sole right to set a minimum price threshold for each Accelerated Purchase in the notice provided with respect to such Accelerated Purchase and under certain circumstances and in accordance with the Purchase Agreement the Company may direct multiple Accelerated Purchases in a day.

The aggregate number of shares that the Company can sell to Lincoln Park under the Purchase Agreement may not exceed 325,357 shares of the Common Shares (which is equal to approximately 19.99% of the shares of the Common Shares outstanding

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immediately prior to the execution of the Purchase Agreement) (the “Exchange Cap”), unless (i) shareholder approval is obtained to issue Purchase Shares above the Exchange Cap, in which the Exchange Cap will no longer apply, or (ii) the average price of all applicable sales of Common Shares to Lincoln Park under the Purchase Agreement equals or exceeds $160.50 per share; provided that at no time may Lincoln Park (together with its affiliates) beneficially own more than 4.99% of the Company’s issued and outstanding Common Shares.

The Purchase Agreement contains customary representations, warranties, covenants, closing conditions, indemnification and termination provisions. The Purchase Agreement may be terminated by the Company at any time, at its sole discretion, without any cost or penalty, by giving one business day notice to Lincoln Park. Further, Lincoln Park has covenanted not to engage in any direct or indirect short selling or hedging of the Common Shares. There are no limitations on the use of proceeds, financial or business covenants, restrictions on future financings (other than restrictions on the Company’s ability to enter into a similar type of agreement or Equity Line of Credit during the Term, excluding an At-The-Market transaction with a registered broker-dealer), rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement.

At-the-Market Offering Program

In September 2022, the Company entered into a Controlled Equity Offering Sales Agreement (the "Cantor Sales Agreement") with Cantor Fitzgerald & Co ("Cantor"), under which the Company could have sold, from time to time, shares of the Company’s common stock having an aggregate offering price of up to $50.0 million in “at the market” offerings (the "ATM Offering Program") through Cantor. In August 2023, the Company supplemented its prospectus, dated September 9, 2022 (the “Prospectus Supplement”), to increase the aggregate offering amount under the ATM Offering Program to $50.0 million as the Company was no longer subject to General Instruction I.B.6. of Form S-3, which limited the amounts that the Company could sell under the ATM Offering Program. In April 2024, the Company supplemented the prospectus to reduce the aggregate offering amount under the ATM Offering Program to approximately $6.8 million, which was less than one-third of our public float, as calculated on the day of filing. Sales of the shares of common stock were made at prevailing market prices at the time of sale, or as otherwise agreed with Cantor. Cantor received a commission from the Company of up to 3.0% of the gross proceeds of any shares of common stock sold under the Sales Agreement. During the three months ended March 31, 2024, the Company sold an aggregate of 83,948 shares of common stock at a weighted-average price of $11.07 per share for gross proceeds of approximately $0.9 million under the ATM Offering Program. Offering costs, including commissions, of approximately $0.1 million were recorded as an offset to gross proceeds within additional paid-in capital.

Registered Direct Offerings

The May 2023 Registered Direct Offering included the issuance and sale of an aggregate of 188,000 shares of the Company’s common stock at a purchase price of $16.375 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the May 2023 Pre-Funded Warrants, which were immediately exercised, and the May 2023 Common Stock Warrants. The Company received gross proceeds from the May 2023 Registered Direct Offering of $7.5 million with net proceeds of approximately $6.7 million after deducting $0.8 million in commissions and other transaction costs.

In connection with the May 2023 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0% of the gross proceeds received by the Company from the offering and a management fee equal to 1.0% of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $75,000 for non-accountable expenses and $15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the May 2023 Placement Agent Warrants, equal to 7.0% of the aggregate number of shares of common stock and pre-funded warrants placed in the offering.

The June 2023 Registered Direct Offering included the issuance and sale of an aggregate of 238,000 shares of the Company’s common stock at a purchase price of $28.125 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the June 2023 Pre-Funded Warrants, which were immediately exercised, and the June 2023 Common Stock Warrants. The Company received gross proceeds from the June 2023 Registered Direct Offering of $8.7 million with net proceeds of approximately $7.8 million after deducting $0.9 million in commissions and other transaction costs.

In connection with the June 2023 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0% of the gross proceeds received by the Company from the offering and a management fee equal to 1.0% of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $50,000 for non-accountable expenses and $15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the June 2023 Placement Agent Warrants, equal to 7.0% of the aggregate number of shares of common stock and pre-funded warrants placed in the offering.

The January 2024 Registered Direct Offering included the issuance and sale of an aggregate of 338,000 shares of the Company’s common stock at a purchase price of $10.075 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the January 2024 Pre-Funded Warrants and the January 2024 Common Stock Warrants. The Company received gross proceeds from the January 2024 Registered Direct Offering of $15.0 million with net proceeds of approximately $13.6 million after deducting $1.4 million in commissions and other transaction costs.

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In connection with the January 2024 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0% of the gross proceeds received by the Company from the offering and a management fee equal to 1.0% of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $25,000 for non-accountable expenses, $50,000 for fees and expenses of legal counsel and other out-of-pocket expenses, and $15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the January 2024 Placement Agent Warrants, equal to 7.0% of the aggregate number of shares of common stock and pre-funded warrants placed in the offering.

Preferred Stock

Upon closing of the Business Combination transaction, pursuant to the terms of the Amended and Restated Certificate of Incorporation, 100,000,000 shares of preferred stock with a par value of $0.0001 per share were authorized. eFFECTOR's Board of Directors (the "Board of Directors") has the authority, without further action by the stockholders to issue such shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, and to fix the dividend, voting, and other rights, preferences and privileges of the shares. There were no issued and outstanding shares of preferred stock immediately after the closing of the Business Combination and no preferred stock has been issued as of March 31, 2024.

Sponsor Shares

In connection with the closing of the Business Combination, the LWAC sponsor received 162,250 shares of eFFECTOR common stock, of which 12,000 shares were subject to vesting if, on or prior to August 25, 2024, the price of shares of common stock equals or exceeds $375.00 per share for a period of at least 20 trading days out of 30 consecutive trading days ending on the trading day immediately prior to the date of determination (the "Sponsor Shares"). The 12,000 Sponsor Shares subject to vesting meet the criteria for equity classification, but are not considered outstanding from an accounting perspective. These shares are considered issued but not outstanding as of March 31, 2024 and December 31, 2023, and have been excluded from outstanding shares in the calculation of loss per share for the three months ended March 31, 2024 and 2023.

Employee Stock Purchase Plan

The ESPP provides for six-month offering periods, and at the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. An aggregate of 35,200 shares were initially reserved and available for issuance under the ESPP. The ESPP provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, by 1.0% of the outstanding number of shares of common stock on the immediately preceding December 31, or such lesser amount as determined by our Board of Directors; provided that the total number of shares of common stock that become available for issuance under the ESPP will never exceed 600,000. If our capital structure changes because of a stock dividend, stock split or similar event, the number of shares that can be issued under the ESPP will be appropriately adjusted. As of March 31, 2024, 89,090 shares were reserved for future issuance under the ESPP. There were no shares of common stock issued under the ESPP during the three months ended March 31, 2024 and 2023.

2013 Equity Incentive Plan

Prior to the Business Combination, Old eFFECTOR maintained its 2013 Equity Incentive Plan (the “2013 Plan”), under which Old eFFECTOR granted incentive stock options, restricted stock awards, and other stock-based awards to employees, directors, and non-employee consultants. Upon the completion of the Business Combination, the Company ceased granting awards under the 2013 Plan and, as described below, all awards under the 2013 Plan were converted into awards under the 2021 Plan with the same terms and conditions. In connection with the completion of the Business Combination and the adoption of the 2021 Plan, no further awards will be granted under the 2013 Plan. As of March 31, 2024, the number of shares reserved and options outstanding under the 2013 Plan was 130,617.

2021 Equity Incentive Plan

In connection with the consummation of the Business Combination on August 25, 2021, the Board of Directors approved the adoption of the 2021 Equity Incentive Plan (the “2021 Plan”). As of March 31, 2024, 596,440 shares of common stock are authorized for issuance pursuant to awards under the 2021 Plan, inclusive of any shares of common stock subject to stock options, restricted stock awards or other awards that were assumed in the Business Combination. As of March 31, 2024, 607,306 options to purchase common shares have been awarded and 32,293 shares remain available for issuance under the 2021 Plan. The 2021 Plan permits the granting of incentive stock options, restricted stock awards, other stock-based award or other cash-based awards to employees, directors, and non-employee consultants.

Options granted under the 2021 Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant, or in the case of certain non-statutory options, ten years from the date of grant. The exercise price of

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each option shall be determined by the Board of Directors based on the fair market value of the Company’s stock on the date of the option grant, defined as the closing sales price of the Company's common stock. In the case of incentive stock options, the exercise price shall not be less than 100% of the fair market value of the Company’s common stock at the time the option is granted. For holders of more than 10% of the Company’s total combined voting power of all classes of stock, incentive stock options may not be granted at less than 110% of the fair market value of the Company’s stock at the date of grant and for a term not to exceed five years.

A summary of the Company’s stock option activity under the plans is as follows (in thousands, except share and per share amounts and years):

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2023		480,875		$	51.67		7.3	$	—
Granted		231,800			11.32		9.9
Cancelled or forfeited		(17,911	)		13.53		3.9
Outstanding at March 31, 2024		694,764		$	39.19		7.9	$	1,039
Vested and exercisable at March 31, 2024		325,122		$	56.29		6.3	$	151

For the three months ended March 31, 2024 the total fair value of vested options was $1.0 million. The weighted-average grant date fair value of employee and non-employee option grants during the three months ended March 31, 2024 was $8.27 per share.

Stock-Based Compensation Expense

The Company recognized stock-based compensation expense specifically related to stock options of $1.0 million and $1.2 million for three months ended March 31, 2024 and 2023, respectively. The assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows:

	Three Months Ended March 31,
	2024	2023
Risk-free interest rate	4.3%	3.6% - 4.1%
Expected volatility	84% - 85%	84%
Expected term (in years)	5.3 - 6.0	5.3 - 6.1
Expected dividend yield	0%	0%

Risk-free interest rate. The risk-free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options.

Expected volatility. Due to the Company’s limited operating history and lack of company-specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available.

Expected term. The expected term of stock options represents the weighted-average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term as provided by the SEC. The simplified method calculates the expected term as the weighted average of the time-to-vesting and the contractual life of the options.

Expected dividend yield. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends.

Forfeitures. The Company reduces stock-based compensation expense for actual forfeitures during the period in which they occur.

As of March 31, 2024, the unrecognized compensation cost related to outstanding employee options was $5.6 million and is expected to be recognized as expense over approximately 2.8 years. Unrecognized compensation cost related to outstanding nonemployee options was $0.6 million as of March 31, 2024, and is expected to be recognized as expense over approximately 1.0 year.

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Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consists of the following as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023
Stock options issued and outstanding		694,764		480,875
Public warrants issued and outstanding		233,332		233,332
Private placement warrants issued and outstanding		7,266		7,266
Common stock warrants issued and outstanding		2,257,426		768,592
Placement agent warrants issued and outstanding		158,017		53,799
Pre-funded warrants		653,000		—
Unvested sponsor shares		12,000		12,000
Authorized for future stock awards or option grants		32,293		96,449
Authorized for future issuances under the ESPP		89,090		59,144
Total		4,137,188		1,711,457

9. License Agreements

In May 2013, the Company entered into an agreement with the Regents of the University of California (“UCSF”) which provides the Company with an exclusive license to UCSF’s patent rights in certain inventions (the “UCSF Translational Profiling Patent Rights”) relating to translational profiling laboratory techniques initially developed at UCSF. Under the agreement, the Company is permitted to research, develop, make and sell products that it discovers and develops utilizing the UCSF Translational Profiling Patent Rights, which the Company refers to as licensed products, and use certain licensed processes utilizing the UCSF Translational Profiling Patent Rights and to sublicense such licensed products and processes.

In July 2021, the Company entered into an amendment to the license agreement to confirm the impact of the Business Combination on the license agreement, including clarifying that in connection with the closing of the Business Combination, the Company would pay UCSF a one-time cash payment of approximately $1.0 million. The $1.0 million payment was made to UCSF in August 2021 in connection with the close of the Business Combination. The Company is also required to make cash milestone payments to UCSF upon the completion of certain clinical and regulatory milestones for the licensed products. No milestone events occurred during the three months ended March 31, 2024 and March 31, 2023. The aggregate remaining potential milestone payments are approximately $375,000.

The Company pays an annual minimum royalty of $15,000 to UCSF. All license related fees are recorded as research and development expense.

10. Research Collaboration and License Agreement

In December 2019, the Company entered into a Research Collaboration and License Agreement (the “Pfizer Agreement”) with Pfizer to research and develop small molecules that target eIF4E.

Under the Pfizer Agreement, the Company was responsible for initial research in collaboration with Pfizer, and Pfizer is responsible for all further development of the program, including submission of an investigational new drug application and conducting all clinical development and commercialization activities. Pfizer is obligated to use commercially reasonable efforts to develop and seek regulatory approval for a licensed product, and commercialize a licensed product where Pfizer has received regulatory approval, in the United States and certain other countries. In the event the Company exercises its co-funding and co-promotion option, a joint steering committee will oversee the development plan and budget of the co-developed product, and the Company will have the responsibility to conduct a portion of product marketing presentations to healthcare providers.

Pursuant to the Pfizer Agreement, the Company received an upfront, one-time, non-refundable, non-creditable payment of $15 million from Pfizer. Pfizer was obligated to reimburse the Company for costs incurred for research performed, up to a specified cap in the low double-digit millions. Upon the achievement of specified early development and regulatory milestones, Pfizer will be obligated to pay the Company up to $80 million in the aggregate. For other non-early stage development milestones Pfizer’s payment obligations to the Company depends upon whether the Company has exercised its co-funding and co-promotion option: 1) if it does not exercise the option, non-early stage development payments may total up to $165 million in aggregate, and 2) if it does exercise the option, non-early stage development payments may total up to $70 million in aggregate. Upon the achievement of specified sales milestones, Pfizer is also obligated to make tiered milestone payments of up to $235 million in aggregate. On a product-by-product basis, Pfizer will also be required to pay the Company high single-digit percentage royalties on annual net sales of each licensed product. If the Company exercises its co-promotion and co-funding option, royalty payments will exclude sales in the United States and the Company will share with Pfizer profits from sale of the relevant licensed product in the United States.

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The initial transaction price of $27.0 million was allocated to the two performance obligations on a relative standalone value basis, with $25.6 million allocated to the license and $1.4 million allocated to the research activities, which were completed in 2020. The value attributable to the license was recognized upon delivery of the license to Pfizer and the value attributable to the research activities was recognized pro-rata based on the actual costs incurred by the Company compared to the total estimated costs of the research activities from the time of execution to the end of the research program.

There was no revenue recorded in connection with this agreement for the three months ended March 31, 2024 and 2023 because all development and sales milestones (variable consideration) were fully constrained.

11. Commitments and Contingencies

Leases

In September 2021, the Company entered a non-cancelable three-year lease for certain office space in Solana Beach, California, with an option to renew for an additional three-year term. In January 2024, the Company executed a three-year extension to the lease with a new expiration date of October 31, 2027. The initial term of the lease started on November 1, 2021, and is serving as the Company's headquarters. Rent expense under this lease was $18,000 and $16,000 for the three months ended March 31, 2024 and 2023, respectively.

During the three months ended March 31, 2024 and 2023, the Company paid $19,000 and $14,000 in lease payments, respectively, which were included in operating activities in the statements of cash flows.

The following table summarizes supplemental balance sheet information related to leases as of March 31, 2024 and December 31, 2023 (in thousands):

	March 31, 2024		December 31, 2023
Assets:
Operating lease right-of-use assets	$	225	$	53
Total right-of-use assets		225		53
Liabilities
Operating lease liabilities, current		53		60
Operating lease liabilities, non-current		179		—
Total operating lease liabilities	$	232	$	60

As of March 31, 2024, the future minimum annual lease payments under the existing operating leases were as follows (in thousands, except for weighted-average remaining lease term and weighted-average discount rate):

Remainder of 2024	$	56
2025		77
2026		79
2027		68
Total remaining lease payments		280
Less: imputed interest		(48	)
Total operating lease liabilities		232
Less: current portion		(53	)
Long-term operating lease liabilities	$	179
Weighted-average remaining lease term (in years)		3.60
Weighted-average discount rate		11.5	%

12. Employee Benefits

The Company has a defined contribution 401(k) plan available to eligible employees. Under the terms of the plan, employees may make voluntary contributions as a percent of compensation, limited to the maximum amount allowable under federal tax regulations. The Company, at its discretion, may make certain contributions to the 401(k) plan. Through March 31, 2024, the Company made no matching contributions.

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Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Unless the context otherwise requires, all references in this section to “we,” “our,” “us” or “eFFECTOR” refer to the business of eFFECTOR Therapeutics, Inc. prior to the consummation of the Business Combination, which is our business following the consummation of the Business Combination. The following discussion and analysis should be read in conjunction with our unaudited condensed consolidated financial statements and notes thereto included elsewhere in this Quarterly Report on Form 10-Q and with our audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K, filed with the SEC on March 26, 2024.

Cautionary Note Regarding Forward-Looking Statements

This Quarterly Report contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements other than statements of historical facts contained in this Quarterly Report, including statements regarding our future results of operations or financial condition, research and development plans, the anticipated timing, costs, design and conduct of our ongoing and planned preclinical studies and planned clinical trials for our 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 to develop future product candidates, the potential benefits of strategic collaborations, the timing and likelihood of success, plans and objectives of management for future operations, and future results of anticipated product development efforts, are forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “could,” “expect,” “intend,” "target," “plan,” “anticipate,” “believe,” “estimate,” “predict,” “potential,” “continue,” or the negative of these terms or other similar expressions. These forward-looking statements 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, financial condition and results of operations. These forward-looking statements speak only as of the date of this Quarterly Report and are subject to a number of risks, uncertainties and assumptions, including those described in Part II, Item 1A, “Risk Factors” in this Quarterly Report on Form 10-Q and in Part I, Item 1A, “Risk Factors” in our Annual Report on Form 10-K, filed with the SEC on March 26, 2024. 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. Except as required by applicable law, we do not plan 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.

Overview

We are a clinical-stage biopharmaceutical company focused on pioneering the development of a new class of oncology drugs we refer to as STRIs. Translation is the process in cells whereby the production of proteins is directed by information contained in genetic sequences. We utilized our proprietary selective translation regulation technology platform to internally discover a portfolio of small molecule STRI product candidates. Our product candidates target the eIF4F complex and its activating kinase, mitogen-activated protein interacting kinase (“MNK”). The eIF4F complex is a central node where two of the most frequently mutated signaling pathways in cancer, the PI3K-AKT and RAS-MEK pathways, converge to activate the translation of select mRNA into proteins that are frequent culprits in key disease-driving processes. Inhibition of any one of these targets simultaneously downregulates multiple disease-driving proteins before they are produced. Each of our product candidates is designed to act on a single protein that drives the expression of a network of multiple functionally related proteins, including oncoproteins, which are proteins whose aberrant function can cause cancer, immunosuppressive proteins in T cells and proteins known to drive drug resistance that together control tumor growth, survival and immune evasion.

Our lead product candidate, zotatifin, is an inhibitor of eIF4A, a component of the eIF4F complex, and is currently being evaluated in a Phase 1/2 clinical trial in patients with certain solid tumors. We have completed the initial dose escalation portion of this trial as well as the initial Phase 2 expansion portion in certain indications, including the evaluation of zotatifin in combination with fulvestrant and abemaciclib (“ZFA triplet”) in patients with ER+ breast cancer. In light of the favorable safety results observed in the Phase 1/2 clinical trial and target engagement data generated to date, we resumed dose escalation of zotatifin dosed every other week, initially in combination with fulvestrant ("ZF doublet"), in patients with ER+ breast cancer to determine if a higher dose of zotatifin can be utilized in future clinical studies. Subsequently we also initiated dose escalation in the ZFA triplet. In the first quarter of 2024, dose escalation of the ZF doublet concluded with the determination of 0.2 mg/kg zotatifin Q2W as the RP2D for the doublet.

To date, we’ve reported interim data from five cohorts including patients with ER+ breast cancer, which demonstrated that zotatifin was generally well tolerated and showed signals of activity, including partial responses in heavily pretreated ER+ breast cancer patients. We reported topline results for the fully enrolled ZFA triplet cohort in ER+ breast cancer at the American Society of Clinical Oncology (“ASCO”) 2023 Annual Meeting in June, where partial responses were observed in 5 of 19 (26%) evaluable patients treated with the ZFA triplet. In addition, a partial response was observed in 1 of 3 (33%) patients in the first resumed dose escalation cohort of the ZF doublet. Both ZFA and ZF combinations were generally well tolerated with a large majority of adverse events Grade 1 or 2. We reported mature data for the ZFA triplet cohort at the 2023 San Antonio Breast Cancer Symposium

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(SABCS®) in December, where median PFS was 7.4 months. We anticipate reporting additional data, including the RP2D for the ZFA triplet, in the second half of 2024.

If zotatifin continues to demonstrate an adequate safety profile and sufficient signals of activity, we plan to continue clinical development of zotatifin, potentially as a combination in a randomized trial against a relevant comparator control group. We are currently evaluating plans to test the ZFA triplet in a randomized trial after we finalize the dose and schedule in the second half of 2024. We anticipate interacting with FDA on development strategy utilizing the fast-track designation received in 2023.

Our other clinical-stage product candidate, tomivosertib, is an oral small-molecule inhibitor of MNK that we tested in combination with inhibitors of anti-PD-(L)1 therapy, for the treatment of patients with solid tumors. In the second quarter of 2021, we initiated dosing in KICKSTART, our randomized Phase 2b clinical trial evaluating tomivosertib in combination with pembrolizumab in patients with metastatic non-small cell lung cancer (“NSCLC”) with PD-L1 expression level greater than or equal to 50% (“PD-L1≥50%”). Pembrolizumab is owned and marketed by Merck for frontline NSCLC and several other indications. We reported topline results from the primary analysis of this trial in April 2024. The hazard ratio for progression free survival, based on 36 events, was 0.62 (95% confidence intervals 0.3 to 1.3) using a stratified COX proportional hazards model, with a two-sided p value for PFS of 0.21, which did not meet the pre-specified threshold of 0.2. Based on the totality of the data available as of the primary analysis, we do not see an obvious path forward to continue developing tomivosertib in frontline NSCLC.

Since our inception in 2012 we have devoted substantially all of our resources to raising capital, identifying potential product candidates, establishing our intellectual property portfolio, conducting preclinical studies and clinical trials, establishing arrangements with third parties for the manufacture of our product candidates and related raw materials, and providing general and administrative support for these operations. We do not have any products approved for sale and have not generated any revenue from product sales. As of March 31, 2024, we have raised a total of $341.8 million to fund our operations, comprised of aggregate gross proceeds of $150.0 million from the sale and issuance of convertible preferred stock, gross proceeds of $67.0 million from the issuance of common stock in connection with the Business Combination in August 2021, $42.0 million in collaboration revenue under our research collaboration and license agreement with Pfizer ("Pfizer Agreement"), $35.0 million from loans under credit facilities, $31.2 million in gross proceeds from the sale of common stock in the May 2023 Registered Direct Offering (as defined below), June 2023 Registered Direct Offering (as defined below) and January 2024 Registered Direct Offering (as defined below), $8.5 million in gross proceeds from the sale of common stock under our Controlled Equity Offering Sales Agreement (“Sales Agreement”) with Cantor Fitzgerald & Co ("Cantor") ("ATM Offering Program"), $5.0 million in grant revenue under the Research Subaward Agreement with The Regents of the University of California, on behalf of its San Francisco campus ("UCSF"), and $3.1 million in gross proceeds from the sale of common stock under the equity purchase agreement ("Purchase Agreement") with Lincoln Park Capital Fund, LLC ("Lincoln Park"). Other than with respect to the net income generated as a result of revenue under the Pfizer Agreement generated in 2020 and the net income generated in 2021 as a result of the change in valuation of the earn-out liability in 2021, we have incurred significant operating losses since our inception. Our net loss for the three months ended March 31, 2024 was $8.8 million and our net income for the three months ended March 31, 2023 was $10.0 million. As of March 31, 2024, we had an accumulated deficit of $188.2 million. Substantially all of our operating losses resulted from expenses incurred in connection with the research and development of our product candidates and general and administrative costs associated with our operations.

We expect to continue to incur significant expenses and losses for at least the next several years. We anticipate our expenses will increase substantially as we continue our development of, seek regulatory approval for and potentially commercialize any approved product candidates, hire additional personnel, protect our intellectual property and incur additional costs associated with being a public company. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of our clinical trials and preclinical studies and our expenditures on other research and development activities. As of March 31, 2024, we had $25.4 million in cash, cash equivalents and short-term investments. To fund further operations, we will need to raise additional capital. Our current capital resources will not be sufficient for us to complete the clinical development of any of our product candidates or, if applicable, to prepare for commercializing any product candidate which may receive approval from the FDA or comparable foreign regulatory authority. Accordingly, we expect to finance our cash needs through a combination of equity offerings, debt financings, or other capital sources, including potential additional collaborations, licenses, and other similar arrangements. Adequate funding may not be available to us on acceptable terms, if at all. Our failure to raise capital or enter into such other arrangements when needed would have a negative impact on our financial condition and could force us to delay, limit, reduce, or terminate our research and development programs or other operations, or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Reverse Stock Split

On January 9, 2024, we filed a Certificate of Amendment to our Amended and Restated Certificate of Incorporation, as amended to date, with the Secretary of State of the State of Delaware to effect a reverse stock split of our common stock at a ratio of 1-for-25 (the “Reverse Stock Split”), as authorized at our 2023 annual meeting of stockholders held on June 22, 2023. We effected the Reverse Stock Split on January 12, 2024. The number of shares of common stock that we are authorized to issue was proportionally reduced from 1,000,000,000 shares to 40,000,000 shares and the par value of its common stock remains unchanged at $0.0001 per share.

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Share and per share amounts in this Quarterly Report are presented after giving effect to the Reverse Stock Split. Proportionate adjustments were made to the per share exercise price and number of shares of common stock issuable under all outstanding stock options and warrants. In addition, proportionate adjustments have been made to the number of shares of common stock reserved for our equity incentive compensation plans.

Financial Operations Overview

Revenue

We currently have no products approved for sale, and all revenue generated has been from the Pfizer Agreement along with grant revenue. In the future, we may generate additional revenue from collaboration, grant or license agreements we have entered into, or may enter into, with respect to our product candidates, as well as product sales from any approved product. Our ability to generate product revenues will depend on the successful development and eventual commercialization of our product candidates. If we fail to complete the development of our product candidates in a timely manner or to obtain regulatory approval for our product candidates, our ability to generate future revenue and our results of operations and financial position would be materially adversely affected.

Pfizer Agreement

In December 2019, we entered into the Pfizer Agreement, to research and develop small molecules that target eIF4E. Pursuant to the Pfizer Agreement, we granted Pfizer a worldwide, exclusive license, with a right to sublicense, under certain of our patents, know-how, and materials to use, develop, manufacture, commercialize, and otherwise exploit compounds or products targeting eIF4E, for any and all indications. Under the agreement, we were responsible for initial research in collaboration with Pfizer, and Pfizer is responsible for all further development of this development program, including submission of an IND and conducting all clinical development and commercialization activities.

Pursuant to the Pfizer Agreement, we received an upfront, one-time, non-refundable, non-creditable payment of $15 million dollars from Pfizer. Pfizer was obligated to reimburse us for costs incurred for research performed, up to a specified cap in the low double-digit millions. Upon the achievement of specified development, regulatory and sales milestones, Pfizer will be obligated to pay us up to $480 million dollars in the aggregate, as well as to pay us high single-digit percentage royalties on annual net sales of each licensed product. See “Business — Our Collaboration and License Agreements” in our Annual Report on Form 10-K filed with the SEC on March 26, 2024, for additional information about this agreement, including with respect to potential payments to us thereunder.

Operating Expenses

Research and Development Expenses

Research and development expenses primarily consist of costs associated with the preclinical and clinical development of our product candidates. Our research and development expenses include:

•external costs, including:

•expenses incurred under arrangements with third parties, such as CROs and consultants and advisors that perform biology, chemistry, toxicology, clinical and regulatory functions;

•costs related to acquiring and manufacturing preclinical and clinical trial materials, including continued testing such as process validation and stability of drug product;

•costs related to toxicology testing and other research and preclinical studies; and

•costs related to compliance with regulatory requirements and license fees.

•internal costs, including:

•salaries and related overhead expenses, which include stock-based compensation and benefits, for personnel in research and development functions; and

•facilities, depreciation, insurance and other expenses related to research and development.

We expense research and development costs as incurred. We account for nonrefundable advance payments for goods and services that will be used in future research and development activities as expenses when the service has been performed or when the goods have been received. We track external expenses on a development program and other program specific basis. However, we do not track internal costs on a program specific basis because these costs primarily relate to personnel and facilities, which are deployed across multiple programs under development.

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The following table summarizes our research and development expenses for the periods indicated (in thousands).

	Three Months Ended March 31,
	2024		2023
External development program expenses:
tomivosertib (eFT508)	$	2,053	$	2,552
zotatifin (eFT226)		1,481		2,218
Unallocated internal research and development expenses:
Personnel related		1,344		1,305
Other		428		534
Total research and development expenses	$	5,306	$	6,609

We expect our research and development expenses to increase substantially for the foreseeable future as we continue the development of our product candidates, particularly as we move into later stages of clinical development which typically cost more. The process of conducting clinical trials and preclinical studies necessary to obtain regulatory approval is costly and time-consuming. We may never succeed in achieving marketing approval for any of our product candidates. At this time, we cannot reasonably estimate the nature, timing or costs of the efforts that will be necessary to complete the remainder of the development of any of our product candidates or the period, if any, in which material net cash inflows from these product candidates may commence. We anticipate we will make determinations as to which product candidates and programs to pursue and how much funding to direct to each product candidate and program on an ongoing basis in response to clinical and preclinical results, regulatory developments, ongoing assessments as to each product candidate’s and program’s commercial potential, and our ability to enter into collaborations, to the extent we determine the resources or expertise of a collaborator would be beneficial for a given product candidate or program.

Our development costs may vary significantly based on factors such as:

•per patient trial costs;

•the number and scope of trials required for approval and preclinical and IND-enabling studies;

•the number of sites included in the trials;

•the length of time required to enroll suitable patients;

•the number of doses that patients receive;

•the number of patients that participate in the trials;

•the drop-out or discontinuation rates of patients;

•the duration of patient follow-up;

•the extent of reimbursement for the costs of approved therapies used in our combination trials;

•potential additional safety monitoring or other studies requested by regulatory agencies;

•the number and complexity of procedures, analyses and tests performed during the trial;

•the phase of development of the product candidate;

•the impact of any interruptions to our operations or to those of the third parties with whom we work due to any healthcare emergencies;

•the efficacy and safety profile of the product candidate; and

•the extent to which we establish additional collaboration, license or other arrangements.

General and Administrative Expenses

General and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation and benefits, and consulting fees for finance, accounting, and other administrative functions. Other costs include legal fees relating to patent and corporate matters, insurance, and facility costs not otherwise included in research and development expenses.

We expect our general and administrative expenses will increase substantially for the foreseeable future as we advance our product candidates through clinical development. In addition, if we obtain regulatory approval for any of our product candidates, we expect to incur expenses associated with building a sales and marketing team if we choose to commercialize such product candidates on our own.

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Other Income (Expense)

Interest Income

Interest income consists of interest earned on our cash equivalents and short-term investments.

Interest Expense

Interest expense recorded in the three months ended March 31, 2024 and 2023 consisted of amounts attributable to our outstanding term loan with Oxford Financial LLC (“Oxford”).

Other Income (Expense)

We assumed private placement warrants in connection with the Business Combination transaction that are required to be accounted for as liabilities and remeasured to fair value at each reporting date, with changes in the fair value reported as a component of other income (expense).

In January 2022, we entered into the Purchase Agreement with Lincoln Park. We record other expense in connection with costs paid to maintain the Lincoln Park facility.

Results of Operations

Comparison of the three months ended March 31, 2024 and 2023

The following table sets forth our results of operations for the three months ended March 31, 2024 and 2023 (in thousands):

	Three Months Ended March 31,						Period-to- Period
	2024			2023			Change
Operating expenses:
Research and development		5,306			6,609			(1,303	)
General and administrative		3,090			2,927			163
Total operating expenses		8,396			9,536			(1,140	)
Loss from operations		(8,396	)		(9,536	)		1,140
Other income (expense)		(438	)		(478	)		40
Net loss	$	(8,834	)	$	(10,014	)	$	1,180

Research and Development Expenses

Research and development expenses were $5.3 million and $6.6 million for the three months ended March 31, 2024 and 2023, respectively. The decrease in research and development expenses of $1.3 million was primarily due to a $0.7 million decrease for the zotatifin program due to decreased clinical cost related to the oncology trial and a $0.5 million decrease for the tomivosertib program due to reduced costs associated with the KICKSTART trial, along with decreased costs related to drug product manufacturing. Further, there was a $0.1 million decrease in consultant costs in the three months ended March 31, 2024 as compared to the same period in 2023.

General and Administrative Expenses

General and administrative expenses were $3.1 million and $2.9 million for the three months ended March 31, 2024 and 2023, respectively. The increase in general and administrative expenses of $0.2 million was primarily due to a $0.2 million increase in personnel-related costs, and a $0.1 million increase each in consultant and legal costs for the three months ended March 31, 2024 as compared to the three months ended March 31, 2023. These increases were partially offset by a $0.2 million decrease in premiums paid on directors and officers insurance.

Other Income (Expense)

Other expense was $0.4 million and $0.5 million for the three months ended March 31, 2024 and 2023, respectively.

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Liquidity and Capital Resources

Sources of Liquidity

From our inception through March 31, 2024, we have raised a total of $341.8 million to fund our operations, comprised of aggregate gross proceeds of $150.0 million from the sale and issuance of convertible preferred stock, gross proceeds of $67.0 million from the issuance of common stock in connection with the Business Combination in August 2021, $42.0 million in collaboration revenue under our research collaboration and license agreement with Pfizer, $35.0 million from loans under credit facilities, $31.2 million in gross proceeds from the sale of common stock in the May 2023 Registered Direct Offering, June 2023 Registered Direct Offering and January 2024 Registered Direct Offering, $8.5 million in gross proceeds from the sale of common stock under the ATM Offering Program, $5.0 million in grant revenue under the Research Subaward Agreement with UCSF, and $3.1 million in gross proceeds from the sale of common stock to Lincoln Park under the Purchase Agreement ($46.9 million remaining available for sale under the Purchase Agreement as of March 31, 2024).

Our cash and cash equivalents and short-term investments totaled $25.4 million as of March 31, 2024. Until required for use in our business, we typically invest our cash in investments that are highly liquid, readily convertible to cash with original maturities of 1 year or less at the date of purchase. We attempt to minimize the risks related to our cash and cash equivalents and investments by maintaining balances in accounts only with accredited financial institutions and, consequently, we do not believe we are subject to unusual credit risk beyond the normal credit risk associated with ordinary commercial banking relationships.

Oxford Loan Facility

In March 2021, we entered into a Loan and Security Agreement (“Oxford LSA”) with Oxford, pursuant to which we could borrow up to $30.0 million, issuable in two separate tranches of $20.0 million (“Term A Loan”) and $10.0 million (“Term B Loan”), collectively referred to as the Oxford Loans. In March 2021, we borrowed $20.0 million of the Term A Loan. The Term A Loan had an interest-only period that commenced upon the borrowing with interest due and payable upon the first day of each month.

On February 22, 2022, we entered into an amendment to the Oxford LSA whereby the interest only period for the Term A Loans ended on March 1, 2024. In connection with the amendment, the maturity of the Term A Loans was extended from March 18, 2026 to February 1, 2027. We began principal repayment in March 2024 and will make principal payments of approximately $0.6 million on the first of each month through the maturity date of February 1, 2027. The principal payments due under the Oxford Loans, and the related accrued final payment, have been classified as current liabilities as of December 31, 2023 and March 31, 2024, due to our assessment that the material adverse change clause under the Oxford Loans is not within our control. We have not been notified of an event of default by the lender as of the date of this report.

The Term B Loan would have become available upon achievement of certain clinical development milestones, and was available until the earlier of (i) June 30, 2023, (ii) forty-five days after the occurrence of such clinical development milestone, and (iii) the occurrence of an event of default. As we did not achieve the clinical development milestones by June 30, 2023, we no longer have access to the additional $10.0 million under the Term B Loan.

We are required to make a final payment equal to 5.5% of each funded tranche at maturity, which has been recorded as a debt discount and is being amortized over the term of the debt arrangements.

Equity Purchase Agreement with Lincoln Park

On January 24, 2022, we entered into the Purchase Agreement with Lincoln Park which provides for the sale to Lincoln Park up to $50.0 million of shares of our common stock over the thirty-six (36) month term of the Purchase Agreement, subject to certain conditions. In connection with the Purchase Agreement, Lincoln Park made an initial purchase of $3.0 million of shares of common stock, which equated to 22,304 shares of common stock, and we issued 5,717 shares of common stock to Lincoln Park as a commitment fee in connection with entering into the Purchase Agreement. As of March 31, 2024, a total of 1,200 shares of common stock have been sold in addition to the upfront amount, with such shares sold during the three months ended June 30, 2022. The minimum price that we can sell shares to Lincoln Park is $1.00 per share. No assurance can be given that we will sell any additional shares of common stock under the Purchase Agreement, or, if we do, as to the price or amount of shares of common stock that we sell or the dates when such sales will take place.

At-the-Market Offering Program with Cantor

In September 2022, we entered into the Cantor Sales Agreement with Cantor, under which we may, from time to time, sell shares of our common stock having an aggregate offering price of up to $50.0 million (the "ATM Offering Program"). Sales of the shares of common stock will be made at prevailing market prices at the time of sale, or as otherwise agreed with Cantor. We will pay a commission to Cantor of up to 3.0% of the gross proceeds of any shares of common stock sold under the Cantor Sales Agreement. During the three months ended March 31, 2024, we sold an aggregate of 83,948 shares of common stock at a weighted-average price of $11.07 per share for gross proceeds of approximately $0.9 million under the ATM Offering Program. We incurred offering costs in

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connection with the ATM Offering Program, including commissions, of approximately $0.1 million during the three months ended March 31, 2024.

Registered Direct Offerings

In May 2023, we entered into a securities purchase agreement with a single institutional investor in which 188,000 shares of common stock were issued in a registered direct offering (the "May 2023 Registered Direct Offering"). In connection with the May 2023 Registered Direct Offering, we issued 270,015 shares of common stock in the form of pre-funded warrants, which were immediately exercised. In a concurrent private placement, we issued warrants to purchase up to 458,015 shares of common stock with an exercise price of $13.25 per share ("May 2023 Common Stock Warrants"). The May 2023 Common Stock Warrants were exercisable immediately upon issuance and will expire on November 30, 2028, which is five and one-half years from the issuance date. Additionally, we issued H.C. Wainwright & Co., LLC (the "Placement Agent") warrants to purchase up to 32,060 shares of common stock with an exercise price of $20.47 per share ("May 2023 Placement Agent Warrants"). The May 2023 Placement Agent Warrants will expire on May 26, 2028, which is five years following the commencement of sales in the May 2023 Registered Direct Offering. We received gross proceeds from the May 2023 Registered Direct Offering of $7.5 million with net proceeds of approximately $6.7 million after deducting $0.8 million in commissions and other transaction costs.

In June 2023, we entered into an additional securities purchase agreement with the same institutional investor in which 238,000 shares of common stock were issued in a registered direct offering (the "June 2023 Registered Direct Offering"). In connection with the June 2023 Registered Direct Offering, we issued 72,578 shares of common stock in the form of pre-funded warrants, which were immediately exercised. In a concurrent private placement, we issued warrants to purchase up to 310,577 shares of common stock with an exercise price of $25.00 per share ("June 2023 Common Stock Warrants"). The June 2023 Common Stock Warrants were exercisable immediately upon issuance and will expire on December 8, 2028, which is five and one-half years from the issuance date. Additionally, we issued the Placement Agent warrants to purchase up to 21,739 shares of common stock with an exercise price of $35.1575 per share ("June 2023 Placement Agent Warrants"). The June 2023 Placement Agent Warrants will expire on June 6, 2028, which is five years following the commencement of sales in the June 2023 Registered Direct Offering. We received gross proceeds from the June 2023 Registered Direct Offering of $8.7 million with net proceeds of approximately $7.8 million after deducting $0.9 million in commissions and other transaction costs.

In January 2024, we entered into an additional securities purchase agreement with a new single institutional investor in which 338,000 shares of common stock were issued in a registered direct offering (the "January 2024 Registered Direct Offering"). In connection with the January 2024 Registered Direct Offering, we issued 1,150,834 shares of common stock in the form of pre-funded warrants, 497,834 of which were subsequently exercised. We concurrently issued warrants to purchase up to 1,488,834 shares of common stock with an exercise price of $9.95 per share ("January 2024 Common Stock Warrants"). The January 2024 Common Stock Warrants were exercisable immediately upon issuance and will expire on July 29, 2027, which is three and one-half years from the issuance date. Additionally, we issued the Placement Agent warrants to purchase up to 104,218 shares of common stock with an exercise price of $12.5938 per share (“January 2024 Placement Agent Warrants"). The January 2024 Placement Agent Warrants will expire on July 29, 2027, which is three and one-half years following the commencement of sales in the January 2024 Registered Direct Offering. We received gross proceeds from the January 2024 Registered Direct Offering of $15.0 million with net proceeds of approximately $13.6 million after deducting $1.4 million in commissions and other transaction costs.

As of March 15, 2024, our public float was approximately $65.6 million, based on 3,914,309 shares of outstanding common stock held by non-affiliates and at a price of $16.95 per share, which was the last reported sale price of our common stock on the Nasdaq Capital Market on March 4, 2024. As a result of our public float being below $75 million, we were limited by the baby shelf rules until such time as our public float exceeded $75 million, which means we only had the capacity to sell shares up to one-third of our public float under shelf registration statements in any twelve-month period. On April 5, 2024, our public float exceeded $75 million, based on 4,437,540 shares of outstanding common stock held by non-affiliates and at a price of $16.95 per share, the closing price of our common stock on March 4, 2024 which was the highest reported sale price of our common stock on the Nasdaq Capital Market within 60 days of April 5, 2024. As a result of our public float being above $75 million, we are no longer subject to the baby shelf rules.

Funding Requirements

As of March 31, 2024, we had $25.4 million in cash and cash equivalents and short-term investments, which we estimate is sufficient to fund operations into the first quarter of 2025. However, we have prepared cash flow forecasts which indicate that based on our expected operating cash flows, without taking into account future projected cash inflows, there is substantial doubt about our ability to continue as a going concern within twelve months after the date that the financial statements for the three months ended March 31, 2024, are issued. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we expect. Furthermore, our operating plans may change and we may need additional funds sooner than

25

planned. Additionally, the process of testing product candidates in clinical trials is costly, and the timing of progress in these trials is uncertain. Our future capital requirements are difficult to forecast and will depend on many factors, including but not limited to:

•the type, number, scope, progress, expansions, results of and timing of clinical trials and preclinical studies of our product candidates which we are pursuing or may choose to pursue in the future;

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

•the costs of obtaining, maintaining and enforcing our patents and other intellectual property rights;

•the costs and timing of manufacturing for our product candidates, including commercial manufacturing if any product candidate is approved;

•our efforts to enhance operational systems and hire additional personnel to satisfy our obligations as a public company, including enhanced internal controls over financial reporting;

•the costs associated with hiring additional personnel and consultants as our clinical and preclinical activities increase;

•the costs and timing of establishing or securing sales and marketing capabilities if any product candidate is approved;

•our ability to achieve sufficient market acceptance, coverage and adequate reimbursement from third-party payors and adequate market share and revenue for any approved products;

•any delays and cost increases that result from future epidemic diseases;

•the terms and timing of establishing and maintaining additional collaborations, licenses and other similar arrangements; and

•the costs associated with any products or technologies that we may in-license or acquire.

We have no other committed sources of capital, other than potential future sales under the Purchase Agreement with Lincoln Park and the ATM Offering Program with Cantor. Until we can generate a sufficient amount of product revenue to finance our cash requirements, if ever, we expect to finance our future cash needs primarily through equity offerings, debt financings or other capital sources, including potential additional collaborations, licenses and other similar arrangements. However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our stockholders will be or could be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing, if available, may involve agreements that include 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 funds through other collaborations 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 grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our research and development programs or other operations, or grant rights to develop and market product candidates to third parties that we would otherwise prefer to develop and market ourselves.

Cash Flows

The following table sets forth a summary of the net cash flow activity for each of the periods indicated (in thousands):

	Three Months Ended March 31,
	2024			2023
Net cash provided by (used in):
Operating activities	$	(7,278	)	$	(7,637	)
Investing activities		(6,321	)		9,027
Financing activities		14,232			212
Net increase in cash and cash equivalents	$	633		$	1,602

Operating Activities

During the three months ended March 31, 2024, net cash used in operating activities was $7.3 million, which resulted from a net loss of $8.8 million adjusted for changes in operating assets and liabilities and non-cash charges. Non-cash charges and other adjustments included $1.0 million in stock-based compensation, $0.1 million in accretion of discount and amortization of premium on investments, and $0.1 million in non-cash interest expense. Changes in operating assets and liabilities included a $0.7 million decrease in accounts payable due to timing of invoices paid, a $0.9 million increase in accrued expenses due to an increase in research and

26

development accruals, and a $0.3 million decrease in prepaid expenses and other assets related to a decrease in prepaid research and development balance and the amortization of prepaid public company insurance policies.

During the three months ended March 31, 2023, net cash used in operating activities was $7.6 million, which resulted from a net loss of $10.0 million adjusted for changes in operating assets and liabilities and non-cash charges. Non-cash charges and other adjustments included $1.2 million in stock-based compensation, $0.1 million in accretion of discount and amortization of premium on investments, and $0.1 million in non-cash interest expense. Changes in operating assets and liabilities included a $2.2 million increase in accounts payable due to timing of invoices paid, a $0.9 million decrease in accrued expenses due to a decrease in accrued audit fees and decrease in accrued bonus, and a $0.1 million increase in prepaid expenses and other assets related to an increase in prepaid research and development balance offset by the amortization of prepaid public company insurance policies.

Investing Activities

During the three months ended March 31, 2024, net cash used in investing activities was $6.3 million as a result of the purchases of short-term investments, partially offset by maturities during the period.

During the three months ended March 31, 2023, net cash provided by investing activities was $9.0 million as a result of the maturities of short-term investments, partially offset by purchases during the period.

Financing Activities

During the three months ended March 31, 2024, net cash provided by financing activities was $14.2 million, which was primarily the result of net proceeds from the issuance of common stock in the January 2024 Registered Direct Offering as well as net proceeds from the issuance of common stock under the ATM Offering Program during the period.

During the three months ended March 31, 2023, net cash provided by financing activities was $0.2 million, which was the result of net proceeds from the issuance of common stock under the ATM Offering Program during the period.

Critical Accounting Policies and Estimates

There have been no material changes to our critical accounting policies and estimates during the three months ended March 31, 2024 as compared to those disclosed in "Management's Discussion and Analysis of Financial Condition and Results of Operations - Critical Accounting Policies and Estimates," in our Annual Report on Form 10-K for the year ended December 31, 2023, filed with the SEC on March 26, 2024.

Recent Accounting Pronouncements

See Note 2 to our financial statements contained elsewhere in this Form 10-Q for information concerning recent accounting pronouncements.

Item 3. Quantitative and Qualitative Disclosures About Market Risk.

As of March 31, 2024, there have been no material changes surrounding our market risk, including interest rate risk, foreign currency exchange risk, and inflation risk, from the discussion provided in “Management’s Discussion and Analysis of Financial Condition and Results of Operations – Quantitative and Qualitative Disclosures About Market Risk” in our Annual Report on Form 10-K for the year ended December 31, 2023, filed with the SEC on March 26, 2024.

Item 4. Controls and Procedures.

Conclusion Regarding the Effectiveness of Disclosure Controls and Procedures

We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed by us in our reports that we file or submit pursuant to the Exchange Act, is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including our Chief Executive Officer and Chief Financial Officer, as appropriate, to allow for timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives, and management is required to apply its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Under the supervision and with participation of our management, including our Chief Executive Officer and our Chief Financial Officer, we carried out an evaluation of the effectiveness of our disclosure controls and procedures (as such term is defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) as of the end of the period covered by this report.

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Changes in Internal Control over Financial Reporting

There has been no change in our internal control over financial reporting identified in connection with the evaluation required by paragraph (d) of Rules 13a-15 or 15d-15 under the Exchange Act that occurred during the three months ended March 31, 2024, that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

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PART II—OTHER INFORMATION

Item 1. Legal Proceedings.

We are not currently a party to any material legal proceedings. However, from time to time, we may become involved in legal proceedings or be subject to claims arising in the ordinary course of our business. Regardless of outcome, such proceedings or claims can have an adverse impact on us because of defense and settlement costs, diversion of resources and other factors, and there can be no assurances that favorable outcomes will be obtained.

Item 1A. Risk Factors.

We do not believe there have been any material changes to the risk factors disclosed in the section titled “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2023, filed with the SEC on March 26, 2024.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds.

Not applicable.

Item 3. Defaults Upon Senior Securities.

None.

Item 4. Mine Safety Disclosures.

Not applicable.

Item 5. Other Information.

During the three months ended March 31, 2024, none of our officers or directors adopted, modified or terminated any contract, instruction or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any “non Rule 10b5-1 trading arrangement."

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Item 6. Exhibits.

Exhibit Number	Description
3.1	Amended and Restated Certificate of Incorporation of eFFECTOR Therapeutics, Inc. (incorporated by reference to Exhibit 3.1 to the Company’s Form 8-K filed on August 31, 2021).
3.2	Certificate of Amendment to Amended and Restated Certificate of Incorporation of eFFECTOR Therapeutics, Inc. (incorporated by reference to Exhibit 3.1 to the Company’s Form 8-K filed on June 23, 2023).
3.3	Certificate of Amendment to Amended and Restated Certificate of Incorporation of eFFECTOR Therapeutics, Inc. (incorporated by reference to Exhibit 3.1 to the Company’s Form 8-K filed on January 10, 2024).
3.4	Amended and Restated Bylaws of eFFECTOR Therapeutics, Inc. (incorporated by reference to Exhibit 3.2 to the Company’s Form 8-K filed on August 31, 2021).
4.1	Specimen common stock certificate (incorporated by reference to Exhibit 4.1 to the Company’s Form S-4 (333-257091) filed on August 5, 2021).
4.2	Warrant Agreement, dated January 7, 2021, by and between Continental Stock Transfer & Trust Company and Locust Walk Acquisition Corp. (incorporated by reference Exhibit 4.1 to the Company’s Form 8-K filed on January 13, 2021).
4.3	Form of Pre-Funded Warrant (incorporated by reference to Exhibit 4.1 to the Company’s Form 8-K filed on May 30, 2023).
4.4	Form of Common Warrant (incorporated by reference to Exhibit 4.2 to the Company’s Form 8-K filed on May 30, 2023).
4.5	Form of Wainwright Warrant (incorporated by reference to Exhibit 4.3 to the Company’s Form 8-K filed on May 30, 2023).
4.6	Form of Pre-Funded Warrant (incorporated by reference to Exhibit 4.1 to the Company’s Form 8-K filed on June 8, 2023).
4.7	Form of Common Warrant (incorporated by reference to Exhibit 4.2 to the Company’s Form 8-K filed on June 8, 2023).
4.8	Form of Wainwright Warrant (incorporated by reference to Exhibit 4.3 to the Company’s Form 8-K filed on June 8, 2023).
4.9	Form of Pre-Funded Warrant (incorporated by reference to Exhibit 4.1 to the Company’s Form 8-K filed on January 26, 2024).
4.10	Form of Common Warrant (incorporated by reference to Exhibit 4.2 to the Company’s Form 8-K filed on January 26, 2024).
4.11	Form of Wainwright Warrant (incorporated by reference to Exhibit 4.3 to the Company’s Form 8-K filed on January 26, 2024).
10.1+	eFFECTOR Therapeutics, Inc. Amended and Restated Non-Employee Director Compensation Program (incorporated by reference to Exhibit 10.18 to the Company’s Form 10-K filed on March 26, 2024).
10.2+	General Release of Claims, dated as of February 13, 2024, by and between eFFECTOR and Mayank Gandhi (incorporated by reference to Exhibit 10.30 to the Company’s Form 10-K filed on March 26, 2024).
10.3	Form of Securities Purchase Agreement, dated as of January 24, 2024, by and between eFFECTOR and the purchasers named therein (incorporated by reference to Exhibit 10.1 to the Company’s Form 8-K filed on January 26, 2024).
31.1	Certification of Principal Executive Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2	Certification of Principal Financial Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
32.1*	Certification of Principal Executive Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
32.2*	Certification of Principal Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

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101.INS	Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because XBRL tags are embedded within the Inline XBRL document.
101.SCH	Inline XBRL Taxonomy Extension Schema With Embedded Linkbase Documents
104	Cover Page Interactive Data File (embedded within the Inline XBRL document)

+ Indicates a management contract or compensatory plan.

* This certification is deemed not filed for purpose of Section 18 of the Exchange Act or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act.

31

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	eFFECTOR Therapeutics, Inc.
Date: May 9, 2024	By:	/s/ Stephen Worland
		Stephen Worland, Ph.D.
		President and Chief Executive Officer (Principal Executive Officer)

Date: May 9, 2024	By:	/s/ Michael Byrnes
		Michael Byrnes
		Chief Financial Officer (Principal Financial and Accounting Officer)

32

EX-31.1

Exhibit 31.1

CERTIFICATION PURSUANT TO

RULES 13a-14(a) AND 15d-14(a) UNDER THE SECURITIES EXCHANGE ACT OF 1934,

AS ADOPTED PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Stephen T. Worland, certify that:

1.I have reviewed this quarterly report on Form 10-Q of eFFECTOR Therapeutics, Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: May 9, 2024	By:	/s/ Stephen Worland
		Stephen T. Worland, Ph.D.
		President, Chief Executive Officer and Director

EX-31.2

Exhibit 31.2

CERTIFICATION PURSUANT TO

RULES 13a-14(a) AND 15d-14(a) UNDER THE SECURITIES EXCHANGE ACT OF 1934,

AS ADOPTED PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Michael Byrnes, certify that:

1.I have reviewed this quarterly report on Form 10-Q of eFFECTOR Therapeutics, Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d)Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

(a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

(b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: May 9, 2024	By:	/s/ Michael Byrnes
		Michael Byrnes
		Chief Financial Officer

EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of eFFECTOR Therapeutics, Inc. (the “Company”) on Form 10-Q for the period ending March 31, 2024 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

Date: May 9, 2024	By:	/s/ Stephen Worland
		Stephen T. Worland, Ph.D.
		President, Chief Executive Officer and Director

EX-32.2

Exhibit 32.2

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of eFFECTOR Therapeutics, Inc. (the “Company”) on Form 10-Q for the period ending March 31, 2024 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Company.

Date: May 9, 2024	By:	/s/ Michael Byrnes
		Michael Byrnes
		Chief Financial Officer

XML

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	Apr. 30, 2024
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Registrant Name	eFFECTOR Therapeutics, Inc.
Entity Central Index Key	0001828522
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		4,704,409
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity File Number	001-39866
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3306396
Entity Address, Address Line One	142 North Cedros Avenue
Entity Address, Address Line Two	Suite B
Entity Address, City or Town	Solana Beach
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92075
City Area Code	858
Local Phone Number	925-8215
Document Quarterly Report	true
Document Transition Report	false
Common Stock [Member]
Document Information [Line Items]
Trading Symbol	EFTR
Title of 12(b) Security	Common stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Warrant [Member]
Document Information [Line Items]
Trading Symbol	EFTRW
Title of 12(b) Security	Warrants to purchase common stock
Security Exchange Name	NASDAQ

XML

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 15,508	$ 14,875
Short-term investments	9,875	3,495
Prepaid expenses and other current assets	867	1,468
Total current assets	26,250	19,838
Property and equipment, net	190	140
Operating lease right-of-use assets	225	53
Other assets	466	513
Total assets	27,131	20,544
Current liabilities:
Accounts payable	1,713	2,330
Accrued expenses	3,787	2,921
Current term loans, net	18,916	19,385
Accrued final payment on term loans, current	1,100	1,100
Lease liabilities, current portion	53	60
Total current liabilities	25,569	25,796
Other accrued liabilities, non-current	516	503
Non-current warrant liability	40	40
Non-current lease liabilities	179	0
Total liabilities	26,304	26,339
Commitments and contingencies
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 100,000,000 shares authorized at March 31, 2024 and December 31, 2023; zero shares issued and outstanding as March 31, 2024 and December 31, 2023	0	0
Common stock, $0.0001 par value; 40,000,000 shares authorized at March 31, 2024 and December 31, 2023; 3,914,309 shares issued and 3,902,309 shares issued and outstanding as of March 31, 2024; 2,994,679 shares issued and 2,982,679 shares issued and outstanding as of December 31, 2023	0	0
Additional paid-in capital	189,038	173,582
Accumulated other comprehensive income (loss)	0	0
Accumulated deficit	(188,211)	(179,377)
Total stockholders' equity (deficit)	827	(5,795)
Total liabilities and stockholders' equity (deficit)	$ 27,131	$ 20,544

XML

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock price per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	3,914,309	2,994,679
Common stock, shares outstanding	3,902,309	2,982,679

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Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating expenses:
Research and development	$ 5,306	$ 6,609
General and administrative	3,090	2,927
Total operating expenses	8,396	9,536
Operating loss	(8,396)	(9,536)
Other income (expense)
Interest income	323	226
Interest expense	(749)	(689)
Other expense	(12)	(15)
Total other income (expense)	(438)	(478)
Net loss	(8,834)	(10,014)
Comprehensive income (loss):
Net Income (Loss)	(8,834)	(10,014)
Other comprehensive income	0	19
Comprehensive loss	$ (8,834)	$ (9,995)
Net income (loss) per share attributable to common shareholders:
Net loss per share - Basic	$ (2.16)	$ (5.96)
Net loss per share - diluted	$ (2.16)	$ (5.96)
Weighted-average common shares outstanding:
Weighted average common shares outstanding - basic	4,081,580	1,680,032
Weighted average common shares outstanding - diluted	4,081,580	1,680,032

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Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2022	$ 3,896	$ 0	$ 147,480	$ (18)	$ (143,566)
Balance, shares at Dec. 31, 2022		1,667,602
Stock option exercises	0
Issuance of common stock, net of issuance costs, value	119		119
Issuance of common stock, net of issuance costs, shares		16,433
Stock-based compensation expense	1,167		1,167
Unrealized loss on short-term investments	19			19
Net Income (Loss)	(10,014)				(10,014)
Balance at Mar. 31, 2023	(4,813)	$ 0	148,766	1	(153,580)
Balance, shares at Mar. 31, 2023		1,684,035
Balance at Dec. 31, 2023	$ (5,795)	$ 0	173,582		(179,377)
Balance, shares at Dec. 31, 2023	2,982,679	2,982,679
Stock Option And Prefunded Warrant Exercises shares		497,834
Issuance of common stock, net of issuance costs, value	$ 14,446		14,446
Issuance of common stock, net of issuance costs, shares		421,796
Stock-based compensation expense	1,010		1,010
Net Income (Loss)	(8,834)				(8,834)
Balance at Mar. 31, 2024	$ 827	$ 0	$ 189,038	$ 0	$ (188,211)
Balance, shares at Mar. 31, 2024	3,902,309	3,902,309

XML

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities:
Net Income (Loss)	$ (8,834)	$ (10,014)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization expense	28	28
Accretion of discount and amortization of premium on investments, net	(60)	(119)
Stock-based compensation	1,010	1,167
Other expense related to equity purchase agreement	12	15
Non-cash interest expense	87	76
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	267	(180)
Other non-current assets	53	48
Accounts payable	(716)	2,225
Accrued expenses	875	(886)
Operating lease right-of-use assets and liabilities, net	0	3
Net cash used in operating activities	(7,278)	(7,637)
Investing activities:
Purchases of fixed assets	0	(13)
Maturities of short-term investments	3,500	12,000
Purchases of short-term investments	(9,821)	(2,960)
Net cash provided by (used in) investing activities	(6,321)	9,027
Financing activities:
Repayment of term loans	(556)	0
Proceeds from exercise of common stock options and prefunded warrants	1	0
Proceeds from issuance of common stock, net of issuance costs	14,787	212
Net cash provided by financing activities	14,232	212
Net increase in cash and cash equivalents	633	1,602
Cash and cash equivalents at beginning of period	14,875	8,708
Cash and cash equivalents at end of period	15,508	10,310
Supplemental disclosure of cash flow information
Interest paid	655	589
Operating lease liabilities arising from obtaining right-of-use assets	186	0
Supplemental disclosure of non-cash investing and financing activities:
Accrued issuance costs	$ 109	$ 170

XML

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (8,834)	$ (10,014)

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Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arrangement Modified	false
Non-Rule 10b5-1 Arrangement Modified	false

XML

Organization and Basis of Presentation

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Basis of Presentation

1. Organization and Basis of Presentation

Description of Business

Locust Walk Acquisition Corp. ("LWAC”) was initially formed on October 2, 2020 as a Delaware corporation formed for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or other similar business transaction with one or more operating businesses.

On May 26, 2021, LWAC entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Locust Walk Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of LWAC (“Merger Sub”), and eFFECTOR Therapeutics, Inc., a Delaware corporation (“ Old eFFECTOR”).

Pursuant to the terms of the Merger Agreement, a business combination between LWAC and Old eFFECTOR was effected through the merger of the Merger Sub with and into Old eFFECTOR, with Old eFFECTOR becoming the surviving company and a wholly-owned subsidiary of LWAC with the name of eFFECTOR Therapeutics Operations, Inc. On August 25, 2021, and in connection with the closing of the business combination (the "Business Combination"), LWAC was renamed eFFECTOR Therapeutics, Inc. ("eFFECTOR" or the "Company"). All outstanding preferred shares of Old eFFECTOR converted into common shares of Old eFFECTOR on a 1:1 basis, which were then converted, along with all outstanding common shares of Old eFFECTOR, into common shares of the surviving eFFECTOR company through application of an exchange ratio of approximately 0.09657.

The Company is a clinical-stage biopharmaceutical company focused on pioneering the development of a new class of oncology drugs the Company refers to as selective translation regulator inhibitors ("STRIs"). The Company’s principal operations are in the United States, with its headquarters in Solana Beach, California. The Company has devoted substantially all of its resources to raising capital, identifying potential product candidates, establishing its intellectual property portfolio, conducting preclinical studies and clinical trials, establishing arrangements with third parties for the manufacture of its product candidates and related raw materials, and providing general and administrative support for these operations. The Company has not generated revenues from its principal operations, other than from licensing and grant revenue, through March 31, 2024.

Reverse Stock Split

On January 9, 2024, the Company filed a Certificate of Amendment to the Company’s Amended and Restated Certificate of Incorporation, as amended to date, with the Secretary of State of the State of Delaware to effect a reverse stock split of the Company’s common stock, par value $0.0001 at a ratio of 1-for-25 (the “Reverse Stock Split”), as authorized at the Company’s 2023 annual meeting of stockholders held on June 22, 2023. The Company effected the Reverse Stock Split on January 12, 2024. No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who otherwise were entitled to a fractional share of common stock were entitled to receive a proportional cash payment. The number of shares of common stock that the Company is authorized to issue was proportionally reduced from 1,000,000,000 shares to 40,000,000 shares and the par value of its common stock remains unchanged at $0.0001 per share.

The Company has retroactively restated the share and per share amounts in the consolidated financial statements as of December 31, 2023 and for the three months ended March 31, 2024 and 2023. Proportionate adjustments were made to the per share exercise price and number of shares of common stock issuable under all outstanding stock options and warrants. In addition, proportionate adjustments have been made to the number of shares of common stock reserved for the Company’s equity incentive compensation plans. The consolidated statements of stockholders’ equity (deficit) and balance sheets reflect the impact of the Reverse Stock Split by reclassifying from “common stock” to “additional paid-in capital” in an amount equal to the par value of the decreased shares resulting from the Reverse Stock Split.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements as of March 31, 2024 and for the three months ended March 31, 2024 and 2023 have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act of 1933, as amended (the “Securities Act”). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. These unaudited financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows. The results for the three months ended March 31, 2024 are not necessarily indicative of the results expected for the full fiscal year or any subsequent interim period. The balance sheet at December 31, 2023 has been derived from the audited financial statements at that date but does not include all the disclosures required by GAAP for complete financial statements. Because all of the disclosures required by GAAP for complete financial

statements are not included herein, these unaudited financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2023 included in its Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 26, 2024.

Liquidity

The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of 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 the outcome of this uncertainty.

Management is required to perform a two-step analysis over its ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (step 2).

The Company has experienced net losses and negative cash flows from operating activities since its inception, aside from the years ended December 31, 2021 and December 31, 2020 when net income was realized as a result of a gain in fair value recognized associated with the earn-out liability and revenue in connection with the Research Collaboration and License Agreement with Pfizer, respectively. The Company has an accumulated deficit of $188.2 million at March 31, 2024. For the three months ended March 31, 2024, the Company used $7.3 million in cash for operations. At March 31, 2024, the Company had cash and cash equivalents and short-term investments of $25.4 million. The Company anticipates that its expenses will increase significantly in connection with its ongoing activities to support its research and development efforts, and it expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. Management has prepared cash flow forecasts which indicate that based on the Company’s expected operating losses and negative cash flows, there is substantial doubt about the Company’s ability to continue as a going concern within twelve months from the date that these financial statements for the three months ended March 31, 2024 are issued. The principal payments due under the Oxford Loans (as defined below), and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed above and the assessment that the material adverse change clause under the Oxford Loans is not within the Company’s control. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements.

The Company’s ability to continue as a going concern is dependent upon its ability to receive additional capital. Management intends to raise additional capital through equity offerings or other capital sources, including potential additional collaborations, licenses and other similar arrangements. Additionally, the Company may receive additional milestone payments from the Research Collaboration and License Agreement with Pfizer (described in Note 10), through the issuance of common stock under the equity purchase agreement with Lincoln Park Capital Fund, LLC (described in Note 8) or through the issuance of common stock under the at-the-market offering program (described in Note 8) with Cantor Fitzgerald & Co. However, the Company may not be able to secure additional financing in a timely manner or on favorable terms, if at all, and may not receive any milestone payments. Without additional capital, the Company may be forced to delay, scale back or eliminate some of its research and development activities, or other operations and potentially delay product development in an effort to provide sufficient funds to continue its operations, or may be required to pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of its stockholders.

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Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.Summary of Significant Accounting Policies

Research and Development Costs

Research and development expenses primarily consist of costs associated with the preclinical and clinical development of the Company’s product candidates. Research and development costs are expensed as incurred.

Clinical Trial Accruals and Preclinical Studies

The Company records expenses resulting from our obligations under contracts with vendors and consultants, CROs and clinical sites in connection with conducting clinical trials and preclinical studies. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects clinical trial and preclinical study expenses in the financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial or preclinical study as measured by the timing of various aspects of the clinical trial, preclinical study, or related activities. The Company determines accrual estimates based on the underlying contracts, correspondence with clinical and other key personnel and third-party service providers as to the progress of the clinical trials, preclinical studies, or other services being conducted, and amounts invoiced or paid to date. During the course of a clinical trial or preclinical study, the Company adjusts the rate of expense recognition if actual results differ from estimates.

Public and Private Placement Warrants

Upon completion of the Business Combination, the Company assumed public and private placement warrants that were issued by LWAC in connection with their initial public offering in January 2021 whereby holders of the public and private placement warrants are entitled to acquire common stock of the Company. The Company has concluded that the public warrants are equity-classified. Since the settlement value of the private placement warrants is dependent, in part, on who holds the warrants at the time of settlement, they are not considered indexed to the Company's stock and are therefore recorded as liabilities. Warrants classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying consolidated statements of operations and comprehensive income (loss). The Company estimates the fair value of these warrants using the Black-Scholes option pricing model.

Stock-Based Compensation Expense

Stock-based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model. The Company accounts for stock options granted to non-employees using the fair value approach.

The Black-Scholes option-pricing model requires the use of subjective assumptions, including the risk-free interest rate, the expected stock price volatility, the expected term of stock options, and the expected dividend yield. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The fair value of the underlying common stock used within the Black-Scholes option-pricing model is based on the closing price of common stock on the date of grant.

Comprehensive Loss

Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company presents comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss.

Cash, Cash Equivalents and Short-term Investments

Cash and Cash Equivalents

The Company considers all highly liquid investments with insignificant interest rate risk and an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase.

Short-term Investments

Short-term investments consist of U.S. Treasury securities, classified as available-for-sale securities and have maturities of greater than three months but less than one year. The Company has classified all of its available-for-sale securities as current assets on the balance sheets because these are considered highly liquid securities and are available for use in current operations. The Company carries these securities at fair value and reports unrealized gains and losses as a separate component of accumulated other comprehensive loss. Amortization and accretion of any purchase premiums or discounts is included in interest income in the consolidated statements of operations and comprehensive loss.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes, based on its preliminary assessment, that the impact of recently issued standards that are not yet effective will not have a material impact on their financial position or results of operations upon adoption.

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as

they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position.

For the three months ended March 31, 2024, all pre-funded warrants that were issued during the January 2024 Registered Direct Offering (as defined below) with an exercise price of $0.001, regardless of whether they were exercised as of March 31, 2024, were considered outstanding in the calculation of basic and diluted net loss per share (See Note 7 for details about pre-funded warrants).

Potentially dilutive securities as of March 31, 2024 and 2023 are as follows (in common stock equivalent shares):

	For the Three Months Ended March 31,
	2024		2023
Common stock warrants		2,257,426		—
Placement agent warrants		158,017		—
Public warrants		233,332		233,332
Private placement warrants		7,266		7,266
Earn-Out Shares		—		200,000
Unvested sponsor shares		12,000		12,000
Stock options outstanding		694,764		473,900
Total		3,362,805		926,498

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Fair Value Measurements

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

Level 2: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability.

Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e. supported by little or no market activity).

The Company’s cash equivalents are classified using Level 1 inputs within the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented.

The Company estimates the fair value of its warrant liabilities at the time of issuance and subsequent remeasurement using the Black-Scholes option pricing model at each reporting date, if required, based on the following inputs: the risk-free interest rates; the expected dividend rates; the remaining contractual life of the warrants; the fair value of the underlying stock; and the expected volatility of the price of the underlying stock. The estimates are based, in part, on subjective assumptions and could differ materially in the future. Changes to these assumptions as well as the fair value of the Company’s stock on the reporting date can have a significant impact on the fair value of the warrant liability.

The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy as of March 31, 2024 and December 31, 2023 (in thousands):

			Fair Value Measurements Using
	March 31,		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	2024		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	6,048	$	6,048	$	—	$	—
U.S. Treasury securities		9,460		—		9,460		—
Short-term investments:
U.S. Treasury securities		9,875		—		9,875		—
Total assets	$	25,383	$	6,048	$	19,335	$	—
Liabilities
Private placement warrant liability	$	40	$	—	$	—	$	40
Total liabilities	$	40	$	—	$	—	$	40

			Fair Value Measurements Using
	December 31,		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	2023		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	10,887	$	10,887	$	—	$	—
U.S. Treasury securities		3,988		—		3,988		—
Short-term investments:
U.S. Treasury securities		3,495		—		3,495		—
Total assets	$	18,370	$	10,887	$	7,483	$	—
Liabilities
Private placement warrant liability	$	40	$	—	$	—	$	40
Total liabilities	$	40	$	—	$	—	$	40

Cash Equivalents and Short-Term Investments

Financial assets measured at fair value on a recurring basis consist of the Company’s cash equivalents and short-term investments. Cash equivalents consisted of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase and short-term investments consisted of U.S. Treasury securities with an original maturity of more than three months at the date of purchase. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, and bids and/or offers.

Investments are classified as Level 1 within the fair value hierarchy if their quoted prices are available in active markets for identical securities. Investments in money market funds of $6.0 million and $10.9 million as of March 31, 2024 and December 31, 2023, respectively, were classified as Level 1 instruments and were included in cash and cash equivalents.

Investments in marketable securities are valued using Level 2 inputs. Level 2 securities are initially valued at the transaction price and subsequently valued and reported upon utilizing inputs other than quoted prices that are observable either directly or indirectly, such as quotes from third-party pricing vendors. Fair values determined by Level 2 inputs, which utilize data points that are observable such as quoted prices, interest rates and yield curves, require the exercise of judgment and use of estimates, that if changed, could significantly affect the Company’s financial position and results of operations. The marketable securities of $19.3 million as of March 31, 2024 were classified as Level 2 instruments, $9.5 million of which is included in cash and cash equivalents and $9.9 million of which is included in short-term investments. The marketable securities of $7.5 million as of December 31, 2023 were classified as Level 2 instruments, $4.0 million of which is included in cash and cash equivalents and $3.5 million of which is included in short-term investments. Accrued interest receivable related to short-term investments was $17,000 and $52,000 as of March 31, 2024 and December 31, 2023, respectively, and included as part of prepaid expenses and other current assets in the condensed balance sheets.

The following tables summarize the Company’s short-term investments accounted for as available-for-sale securities as of March 31, 2024 and December 31, 2023 (in thousands):

				March 31, 2024
	Maturity	Amortized		Unrealized		Unrealized		Estimated
	(in years)	Cost		Gains		Losses		Fair Value
U.S. Treasury securities	1 year or less	$	9,875	$	—	$	—	$	9,875
		$	9,875	$	—	$	—	$	9,875

				December 31, 2023
	Maturity	Amortized		Unrealized		Unrealized		Estimated
	(in years)	Cost		Gains		Losses		Fair Value
U.S. Treasury securities	1 year or less	$	3,495	$	—	$	—	$	3,495
		$	3,495	$	—	$	—	$	3,495

Private Placement Warrant Liability

In connection with the Business Combination, the Company assumed the public and private placement warrants described in Note 2. The private placement warrants are precluded from equity treatment and are recorded as liabilities as they are not considered indexed to the Company's common stock. The private placement warrant liability is measured at fair value, using a combination of observable and unobservable inputs. The change in fair value of the private placement warrant liability is recorded in other income (expense) on the statement of operations and comprehensive loss. The following key assumptions were used in determining the fair value of the private placement warrant liability valued using the Black-Scholes option pricing model as of March 31, 2024 and December 31, 2023:

	March 31, 2024			December 31, 2023
Common stock price	$	14.39		$	11.69
Expected volatility		125.0	%		125.0	%
Risk-free interest rate		4.5	%		4.1	%
Expected term (in years)		2.4			2.7
Expected dividend yield		—			—

The following table presents activity for the private placement warrant liability measured at fair value using significant unobservable Level 3 inputs during the three months ended March 31, 2024 (in thousands):

	Private Placement Warrant Liability
Balance at December 31, 2023	$	40
Change in fair value		—
Balance at March 31, 2024	$	40

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Property and Equipment , net

3 Months Ended

Mar. 31, 2024

Property, Plant and Equipment [Abstract]

Property and Equipment , net

4. Property and Equipment, net

Property and equipment, net consists of the following (in thousands):

	March 31, 2024			December 31, 2023
Lab equipment	$	108		$	30
Computer and office equipment		154			154
Furniture and fixtures		78			78
Leasehold improvements		188			188
Construction in process		14			14
		542			464
Less accumulated depreciation and amortization		(352	)		(324	)
	$	190		$	140

The Company recorded depreciation and amortization expense of approximately $28,000 for each of the three months ended March 31, 2024 and 2023.

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Accrued Expenses

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Accrued Expenses

5. Accrued Expenses

Accrued expenses consist of the following (in thousands):

	March 31, 2024		December 31, 2023
Employee compensation	$	978	$	1,587
Research and development		2,461		1,036
Professional and outside services		131		75
Interest		217		223
	$	3,787	$	2,921

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Term Loans

3 Months Ended

Mar. 31, 2024

Notes and Loans Payable, by Type, Current and Noncurrent [Abstract]

Term Loans

6. Term Loans

Oxford Term Loans

In March 2021, Old eFFECTOR entered into a Loan and Security Agreement (“Oxford LSA”) with Oxford Finance LLC (“Oxford”), pursuant to which the Company may borrow up to $30.0 million, issuable in two separate tranches of $20.0 million (“Term A Loans”) and $10.0 million (“Term B Loans”), collectively referred to as the Oxford Loans. In March 2021, the Company borrowed $20.0 million of the Term A Loans. The Company is required to make a final payment equal to 5.5% of the Term A Loans at maturity, which has been recorded as a debt discount for the Term A Loans and is being amortized over the term of the debt arrangements. In connection with the Oxford LSA, the Company issued warrants to purchase a total of 1,503 shares of Series C Preferred Stock at an exercise price of $133.25 per share.

On February 22, 2022, the Company entered into an amendment to the Oxford LSA whereby the interest only period for the Term A Loans ended on March 1, 2024. In connection with the amendment, the maturity of the Term A Loans was extended from March 18, 2026 to February 1, 2027. Additionally, Term B Loans would have become available to the Company after January 1, 2023 upon achievement of certain clinical development milestones, until the earlier of (i) June 30, 2023, (ii) 45 days after the achievement of certain clinical development milestones, and (iii) the occurrence of an event of default. As the Company did not achieve the clinical development milestones by June 30, 2023, it no longer has access to the additional $10.0 million under the Term B Loans. The amendment was accounted for as a debt modification as the modified debt was not substantially different from the original debt and the cash flows were not significantly changed.

The Oxford Loans carry a variable interest rate equal to the greater of (i) 7.7% and (ii) the sum of the prime rate plus 4.45%. The Company has the option to prepay all, but not less than all, of the borrowed amounts, and there is no prepayment fee for a prepayment made after the third anniversary of the effective date of the Oxford LSA and prior to the maturity date.

The Company’s obligations under the Oxford LSA are secured by a first priority security interest in substantially all of its current and future assets, other than its owned intellectual property. The Company is also obligated to comply with various other customary covenants, including restrictions on its ability to encumber intellectual property assets without consent.

The Company recorded a debt discount of $1.6 million for the estimated fair value of warrants, debt issuance costs, and final payment to be made, which is being amortized to interest expense over the term of the loan using the effective-interest method. As of March 31, 2024, the Company had $19.4 million of outstanding principal under the Term A Loans of which $18.9 million is reflected on the balance sheet net of debt discounts. As of December 31, 2023, the Company had $20.0 million of outstanding principal under the Term A Loans of which $19.4 million is reflected on the balance sheet net of debt discounts. Interest expense, including amortization of debt discount related to the Oxford Term A Loans, totaled $0.7 million for each of the three months ended March 31, 2024 and 2023. The Company is in compliance with all covenants under the Oxford LSA as of March 31, 2024. The Term A Loans include customary events of default, including instances of a material adverse change in our operations, that may require prepayment of the outstanding Term A Loans. The principal payments due under the Oxford Loans, and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed in the Liquidity section of Note 1. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements.

Based on the outstanding principal amounts for the Company’s Term A Loans, the following table sets forth by year the Company’s required future principal payments as of March 31, 2024 (in thousands):

As of March 31, 2024
Remainder of 2024	$	5,000
2025		6,667
2026		6,667
2027		1,110
Required future principal payments	$	19,444
Unamortized debt discount		(528	)
Current term loans, net as of March 31, 2024	$	18,916

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Warrants

3 Months Ended

Mar. 31, 2024

Warrants and Rights Note Disclosure [Abstract]

Warrants

7. Warrants

Assumed Public Warrants and Private Placement Warrants

Following the consummation of the Business Combination, holders of the public warrants and private placement warrants are entitled to acquire common stock of the Company. The warrants became exercisable on January 12, 2022, which is 12 months from the closing of the LWAC's initial public offering. Each warrant entitles the registered holder to purchase one share of common stock at an exercise price of $287.50 per share. The public warrants and private placement warrants will expire on August 25, 2026, which is five years after the completion of the Business Combination.

Once the public warrants and private placement warrants became exercisable, the Company has the right to redeem the outstanding warrants in whole and not in part at a price of $0.25 per warrant upon a minimum of 30 days’ prior written notice of redemption, if and only if the last sale price of the common stock equals or exceeds $450.00 per share for any 20 trading days within a 30-trading day period ending on the third trading day prior to the date on which the Company sends the notice of redemption to the warrant holders.

The private placement warrants are identical to the public warrants except that, so long as they are held by the sponsor or its permitted transferees: (i) they will not be redeemable by the Company; (ii) they may be exercised by the holders on a cashless basis; and (iii) they are subject to registration rights.

Private placement warrants are liability-classified (See Note 3) and the public warrants are equity-classified. The following table summarizes the number of outstanding public warrants and private placement warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023		Exercise Price		Expiration Date
Public warrants		233,332		233,332	$	287.50	August 24, 2026
Private placement warrants		7,266		7,266	$	287.50	August 24, 2026

Warrants - Registered Direct Offerings

In May 2023, the Company completed a registered direct offering (“May 2023 Registered Direct Offering”) which included the issuance of 270,015 shares of common stock in the form of pre-funded warrants with a purchase price of $16.35 per share and an exercise price of $0.025 (the “May 2023 Pre-Funded Warrants”). The May 2023 Pre-Funded Warrants were immediately exercised. Additionally, in a concurrent private placement, the Company issued warrants to purchase up to 458,015 shares of common stock (the “May 2023 Common Stock Warrants”) with an exercise price of $13.25 per share. The May 2023 Common Stock Warrants will expire on November 30, 2028, which is five and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 32,060 shares of common stock ("May 2023 Placement Agent Warrants") with an exercise price of $20.47 per share. The May 2023 Placement Agent Warrants will expire on May 26, 2028, which is five years following the commencement of sales in the May 2023 Registered Direct Offering. See Note 8 for additional detail surrounding the May 2023 Registered Direct Offering.

In June 2023, the Company completed a registered direct offering (“June 2023 Registered Direct Offering”) which included the issuance of 72,578 shares of common stock in the form of pre-funded warrants with a purchase price of $28.10 per share and an exercise price of $0.025 (the “June 2023 Pre-Funded Warrants”). The June 2023 Pre-Funded Warrants were immediately exercised. Additionally, in a concurrent private placement, the Company issued warrants to purchase up to 310,577 shares of common stock (the “June 2023 Common Stock Warrants”) with an exercise price of $25.00 per share. The June 2023 Common Stock Warrants will expire on December 8, 2028, which is five and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 21,739 shares of common stock ("June 2023 Placement Agent Warrants") with an exercise price of $35.1575 per share. The June 2023 Placement Agent Warrants will expire on June 6, 2028, which is five years

following the commencement of sales in the June 2023 Registered Direct Offering. See Note 8 for additional detail surrounding the June 2023 Registered Direct Offering.

In January 2024, the Company completed a registered direct offering (“January 2024 Registered Direct Offering”) which included the issuance of 1,150,834 shares of common stock in the form of pre-funded warrants with a purchase price of $10.074 per share and an exercise price of $0.001 (the “January 2024 Pre-Funded Warrants”), of which 497,834 were exercised as of March 31, 2024. Additionally, the Company concurrently issued warrants to purchase up to 1,488,834 shares of common stock (the “January 2024 Common Stock Warrants”) with an exercise price of $9.95 per share. The January 2024 Common Stock Warrants will expire on July 29, 2027, which is three and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 104,218 shares of common stock ("January 2024 Placement Agent Warrants") with an exercise price of $12.5938 per share. The January 2024 Placement Agent Warrants will expire on July 29, 2027, which is three and one-half years from the issuance date. See Note 8 for additional detail surrounding the January 2024 Registered Direct Offering.

The common stock warrants, placement agent warrants and pre-funded warrants are equity-classified. The following table summarizes the number of outstanding common stock warrants, placement agent warrants and pre-funded warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023		Exercise Price		Expiration Date
May 2023 Common Stock Warrants		458,015		458,015	$	13.25	November 30, 2028
May 2023 Placement Agent Warrants		32,060		32,060	$	20.47	May 26, 2028
June 2023 Common Stock Warrants		310,577		310,577	$	25.00	December 8, 2028
June 2023 Placement Agent Warrants		21,739		21,739	$	35.1575	June 6, 2028
January 2024 Pre-funded Warrants		653,000		—	$	0.001	N/A
January 2024 Common Stock Warrants		1,488,834		—	$	9.95	July 29, 2027
January 2024 Placement Agent Warrants		104,218		—	$	12.5938	July 29, 2027

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Preferred Stock and Stockholders' Equity

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Preferred Stock and Stockholders' Equity

8. Preferred Stock and Stockholders’ Equity (Deficit)

Purchase Agreement

On January 24, 2022, the Company entered into an equity purchase agreement (the “Purchase Agreement”) and a registration rights agreement with Lincoln Park Capital Fund, LLC (“Lincoln Park”) which provides for the sale to Lincoln Park up to $50.0 million of shares (the “Purchase Shares”) of the Company's common stock over the thirty-six (36) month term of the Purchase Agreement. In connection with the Purchase Agreement, Lincoln Park made an initial purchase of $3.0 million of shares of common stock, which equated to 22,304 shares of common stock, and the Company issued 5,717 shares of common stock to Lincoln Park as a commitment fee in connection with entering into the Purchase Agreement. The Company recognized $0.8 million of other expense relating to the commitment fee share issuance. As of March 31, 2024, a total of 1,200 shares of common stock have been sold in addition to the upfront amount, with such shares sold during the three months ended June 30, 2022. There were no purchases under the Purchase Agreement during the three months ended March 31, 2024 and 2023.

Under the Purchase Agreement, the Company has sole discretion, subject to certain conditions, on any business day selected by the Company to require Lincoln Park to purchase up to 1,200 shares of common stock (the “Fully Adjusted Regular Purchase Share Limit”) at the Purchase Price (as defined below) per purchase notice (each such purchase, a “Regular Purchase”). The Fully Adjusted Regular Purchase Share Limit may be increased as follows: to up to 2,000 shares if the closing price is not below $125.00, and up to 3,000 shares if the closing price is not below $250.00. Lincoln Park’s committed obligation under each Regular Purchase is capped at $500,000, unless the Parties agree otherwise. The purchase price for Regular Purchases (the “Purchase Price”) shall be equal to the lesser of: (i) the lowest sale price of the common shares during the Purchase Date (as defined in the Purchase Agreement), or (ii) the average of the three (3) lowest closing sale prices of the common shares during the ten (10) business days prior to the Purchase Date.

In addition to Regular Purchases and subject to certain conditions and limitations, the Company in its sole discretion may require Lincoln Park on each Purchase Date to purchase on the following business day up to the lesser of (i) three (3) times the number of shares purchased pursuant to such Regular Purchase or (ii) 25% of the trading volume on the Accelerated Purchase Date (as defined in the Purchase Agreement) (the “Accelerated Purchase”) (unless the Parties agree otherwise) at a purchase price equal to the lesser of 97% of (i) the closing sale price on the Accelerated Purchase Date, or (ii) the Accelerated Purchase Date’s volume weighted average price (the “Accelerated Purchase Price”). The Company has the sole right to set a minimum price threshold for each Accelerated Purchase in the notice provided with respect to such Accelerated Purchase and under certain circumstances and in accordance with the Purchase Agreement the Company may direct multiple Accelerated Purchases in a day.

The aggregate number of shares that the Company can sell to Lincoln Park under the Purchase Agreement may not exceed 325,357 shares of the Common Shares (which is equal to approximately 19.99% of the shares of the Common Shares outstanding

immediately prior to the execution of the Purchase Agreement) (the “Exchange Cap”), unless (i) shareholder approval is obtained to issue Purchase Shares above the Exchange Cap, in which the Exchange Cap will no longer apply, or (ii) the average price of all applicable sales of Common Shares to Lincoln Park under the Purchase Agreement equals or exceeds $160.50 per share; provided that at no time may Lincoln Park (together with its affiliates) beneficially own more than 4.99% of the Company’s issued and outstanding Common Shares.

The Purchase Agreement contains customary representations, warranties, covenants, closing conditions, indemnification and termination provisions. The Purchase Agreement may be terminated by the Company at any time, at its sole discretion, without any cost or penalty, by giving one business day notice to Lincoln Park. Further, Lincoln Park has covenanted not to engage in any direct or indirect short selling or hedging of the Common Shares. There are no limitations on the use of proceeds, financial or business covenants, restrictions on future financings (other than restrictions on the Company’s ability to enter into a similar type of agreement or Equity Line of Credit during the Term, excluding an At-The-Market transaction with a registered broker-dealer), rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement.

At-the-Market Offering Program

In September 2022, the Company entered into a Controlled Equity Offering Sales Agreement (the "Cantor Sales Agreement") with Cantor Fitzgerald & Co ("Cantor"), under which the Company could have sold, from time to time, shares of the Company’s common stock having an aggregate offering price of up to $50.0 million in “at the market” offerings (the "ATM Offering Program") through Cantor. In August 2023, the Company supplemented its prospectus, dated September 9, 2022 (the “Prospectus Supplement”), to increase the aggregate offering amount under the ATM Offering Program to $50.0 million as the Company was no longer subject to General Instruction I.B.6. of Form S-3, which limited the amounts that the Company could sell under the ATM Offering Program. In April 2024, the Company supplemented the prospectus to reduce the aggregate offering amount under the ATM Offering Program to approximately $6.8 million, which was less than one-third of our public float, as calculated on the day of filing. Sales of the shares of common stock were made at prevailing market prices at the time of sale, or as otherwise agreed with Cantor. Cantor received a commission from the Company of up to 3.0% of the gross proceeds of any shares of common stock sold under the Sales Agreement. During the three months ended March 31, 2024, the Company sold an aggregate of 83,948 shares of common stock at a weighted-average price of $11.07 per share for gross proceeds of approximately $0.9 million under the ATM Offering Program. Offering costs, including commissions, of approximately $0.1 million were recorded as an offset to gross proceeds within additional paid-in capital.

Registered Direct Offerings

The May 2023 Registered Direct Offering included the issuance and sale of an aggregate of 188,000 shares of the Company’s common stock at a purchase price of $16.375 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the May 2023 Pre-Funded Warrants, which were immediately exercised, and the May 2023 Common Stock Warrants. The Company received gross proceeds from the May 2023 Registered Direct Offering of $7.5 million with net proceeds of approximately $6.7 million after deducting $0.8 million in commissions and other transaction costs.

In connection with the May 2023 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0% of the gross proceeds received by the Company from the offering and a management fee equal to 1.0% of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $75,000 for non-accountable expenses and $15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the May 2023 Placement Agent Warrants, equal to 7.0% of the aggregate number of shares of common stock and pre-funded warrants placed in the offering.

The June 2023 Registered Direct Offering included the issuance and sale of an aggregate of 238,000 shares of the Company’s common stock at a purchase price of $28.125 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the June 2023 Pre-Funded Warrants, which were immediately exercised, and the June 2023 Common Stock Warrants. The Company received gross proceeds from the June 2023 Registered Direct Offering of $8.7 million with net proceeds of approximately $7.8 million after deducting $0.9 million in commissions and other transaction costs.

In connection with the June 2023 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0% of the gross proceeds received by the Company from the offering and a management fee equal to 1.0% of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $50,000 for non-accountable expenses and $15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the June 2023 Placement Agent Warrants, equal to 7.0% of the aggregate number of shares of common stock and pre-funded warrants placed in the offering.

The January 2024 Registered Direct Offering included the issuance and sale of an aggregate of 338,000 shares of the Company’s common stock at a purchase price of $10.075 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the January 2024 Pre-Funded Warrants and the January 2024 Common Stock Warrants. The Company received gross proceeds from the January 2024 Registered Direct Offering of $15.0 million with net proceeds of approximately $13.6 million after deducting $1.4 million in commissions and other transaction costs.

In connection with the January 2024 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0% of the gross proceeds received by the Company from the offering and a management fee equal to 1.0% of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $25,000 for non-accountable expenses, $50,000 for fees and expenses of legal counsel and other out-of-pocket expenses, and $15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the January 2024 Placement Agent Warrants, equal to 7.0% of the aggregate number of shares of common stock and pre-funded warrants placed in the offering.

Preferred Stock

Upon closing of the Business Combination transaction, pursuant to the terms of the Amended and Restated Certificate of Incorporation, 100,000,000 shares of preferred stock with a par value of $0.0001 per share were authorized. eFFECTOR's Board of Directors (the "Board of Directors") has the authority, without further action by the stockholders to issue such shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, and to fix the dividend, voting, and other rights, preferences and privileges of the shares. There were no issued and outstanding shares of preferred stock immediately after the closing of the Business Combination and no preferred stock has been issued as of March 31, 2024.

Sponsor Shares

In connection with the closing of the Business Combination, the LWAC sponsor received 162,250 shares of eFFECTOR common stock, of which 12,000 shares were subject to vesting if, on or prior to August 25, 2024, the price of shares of common stock equals or exceeds $375.00 per share for a period of at least 20 trading days out of 30 consecutive trading days ending on the trading day immediately prior to the date of determination (the "Sponsor Shares"). The 12,000 Sponsor Shares subject to vesting meet the criteria for equity classification, but are not considered outstanding from an accounting perspective. These shares are considered issued but not outstanding as of March 31, 2024 and December 31, 2023, and have been excluded from outstanding shares in the calculation of loss per share for the three months ended March 31, 2024 and 2023.

Employee Stock Purchase Plan

The ESPP provides for six-month offering periods, and at the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. An aggregate of 35,200 shares were initially reserved and available for issuance under the ESPP. The ESPP provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, by 1.0% of the outstanding number of shares of common stock on the immediately preceding December 31, or such lesser amount as determined by our Board of Directors; provided that the total number of shares of common stock that become available for issuance under the ESPP will never exceed 600,000. If our capital structure changes because of a stock dividend, stock split or similar event, the number of shares that can be issued under the ESPP will be appropriately adjusted. As of March 31, 2024, 89,090 shares were reserved for future issuance under the ESPP. There were no shares of common stock issued under the ESPP during the three months ended March 31, 2024 and 2023.

2013 Equity Incentive Plan

Prior to the Business Combination, Old eFFECTOR maintained its 2013 Equity Incentive Plan (the “2013 Plan”), under which Old eFFECTOR granted incentive stock options, restricted stock awards, and other stock-based awards to employees, directors, and non-employee consultants. Upon the completion of the Business Combination, the Company ceased granting awards under the 2013 Plan and, as described below, all awards under the 2013 Plan were converted into awards under the 2021 Plan with the same terms and conditions. In connection with the completion of the Business Combination and the adoption of the 2021 Plan, no further awards will be granted under the 2013 Plan. As of March 31, 2024, the number of shares reserved and options outstanding under the 2013 Plan was 130,617.

2021 Equity Incentive Plan

In connection with the consummation of the Business Combination on August 25, 2021, the Board of Directors approved the adoption of the 2021 Equity Incentive Plan (the “2021 Plan”). As of March 31, 2024, 596,440 shares of common stock are authorized for issuance pursuant to awards under the 2021 Plan, inclusive of any shares of common stock subject to stock options, restricted stock awards or other awards that were assumed in the Business Combination. As of March 31, 2024, 607,306 options to purchase common shares have been awarded and 32,293 shares remain available for issuance under the 2021 Plan. The 2021 Plan permits the granting of incentive stock options, restricted stock awards, other stock-based award or other cash-based awards to employees, directors, and non-employee consultants.

Options granted under the 2021 Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant, or in the case of certain non-statutory options, ten years from the date of grant. The exercise price of

each option shall be determined by the Board of Directors based on the fair market value of the Company’s stock on the date of the option grant, defined as the closing sales price of the Company's common stock. In the case of incentive stock options, the exercise price shall not be less than 100% of the fair market value of the Company’s common stock at the time the option is granted. For holders of more than 10% of the Company’s total combined voting power of all classes of stock, incentive stock options may not be granted at less than 110% of the fair market value of the Company’s stock at the date of grant and for a term not to exceed five years.

A summary of the Company’s stock option activity under the plans is as follows (in thousands, except share and per share amounts and years):

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2023		480,875		$	51.67		7.3	$	—
Granted		231,800			11.32		9.9
Cancelled or forfeited		(17,911	)		13.53		3.9
Outstanding at March 31, 2024		694,764		$	39.19		7.9	$	1,039
Vested and exercisable at March 31, 2024		325,122		$	56.29		6.3	$	151

For the three months ended March 31, 2024 the total fair value of vested options was $1.0 million. The weighted-average grant date fair value of employee and non-employee option grants during the three months ended March 31, 2024 was $8.27 per share.

Stock-Based Compensation Expense

The Company recognized stock-based compensation expense specifically related to stock options of $1.0 million and $1.2 million for three months ended March 31, 2024 and 2023, respectively. The assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows:

	Three Months Ended March 31,
	2024	2023
Risk-free interest rate	4.3%	3.6% - 4.1%
Expected volatility	84% - 85%	84%
Expected term (in years)	5.3 - 6.0	5.3 - 6.1
Expected dividend yield	0%	0%

Risk-free interest rate. The risk-free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options.

Expected volatility. Due to the Company’s limited operating history and lack of company-specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available.

Expected term. The expected term of stock options represents the weighted-average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term as provided by the SEC. The simplified method calculates the expected term as the weighted average of the time-to-vesting and the contractual life of the options.

Expected dividend yield. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends.

Forfeitures. The Company reduces stock-based compensation expense for actual forfeitures during the period in which they occur.

As of March 31, 2024, the unrecognized compensation cost related to outstanding employee options was $5.6 million and is expected to be recognized as expense over approximately 2.8 years. Unrecognized compensation cost related to outstanding nonemployee options was $0.6 million as of March 31, 2024, and is expected to be recognized as expense over approximately 1.0 year.

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consists of the following as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023
Stock options issued and outstanding		694,764		480,875
Public warrants issued and outstanding		233,332		233,332
Private placement warrants issued and outstanding		7,266		7,266
Common stock warrants issued and outstanding		2,257,426		768,592
Placement agent warrants issued and outstanding		158,017		53,799
Pre-funded warrants		653,000		—
Unvested sponsor shares		12,000		12,000
Authorized for future stock awards or option grants		32,293		96,449
Authorized for future issuances under the ESPP		89,090		59,144
Total		4,137,188		1,711,457

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License Agreements

3 Months Ended

Mar. 31, 2024

License Agreement Disclosure [Abstract]

License Agreement

9. License Agreements

In May 2013, the Company entered into an agreement with the Regents of the University of California (“UCSF”) which provides the Company with an exclusive license to UCSF’s patent rights in certain inventions (the “UCSF Translational Profiling Patent Rights”) relating to translational profiling laboratory techniques initially developed at UCSF. Under the agreement, the Company is permitted to research, develop, make and sell products that it discovers and develops utilizing the UCSF Translational Profiling Patent Rights, which the Company refers to as licensed products, and use certain licensed processes utilizing the UCSF Translational Profiling Patent Rights and to sublicense such licensed products and processes.

In July 2021, the Company entered into an amendment to the license agreement to confirm the impact of the Business Combination on the license agreement, including clarifying that in connection with the closing of the Business Combination, the Company would pay UCSF a one-time cash payment of approximately $1.0 million. The $1.0 million payment was made to UCSF in August 2021 in connection with the close of the Business Combination. The Company is also required to make cash milestone payments to UCSF upon the completion of certain clinical and regulatory milestones for the licensed products. No milestone events occurred during the three months ended March 31, 2024 and March 31, 2023. The aggregate remaining potential milestone payments are approximately $375,000.

The Company pays an annual minimum royalty of $15,000 to UCSF. All license related fees are recorded as research and development expense.

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Research Collaboration and License Agreement

3 Months Ended

Mar. 31, 2024

Research and Development [Abstract]

Research Collaboration and License Agreement

10. Research Collaboration and License Agreement

In December 2019, the Company entered into a Research Collaboration and License Agreement (the “Pfizer Agreement”) with Pfizer to research and develop small molecules that target eIF4E.

Under the Pfizer Agreement, the Company was responsible for initial research in collaboration with Pfizer, and Pfizer is responsible for all further development of the program, including submission of an investigational new drug application and conducting all clinical development and commercialization activities. Pfizer is obligated to use commercially reasonable efforts to develop and seek regulatory approval for a licensed product, and commercialize a licensed product where Pfizer has received regulatory approval, in the United States and certain other countries. In the event the Company exercises its co-funding and co-promotion option, a joint steering committee will oversee the development plan and budget of the co-developed product, and the Company will have the responsibility to conduct a portion of product marketing presentations to healthcare providers.

Pursuant to the Pfizer Agreement, the Company received an upfront, one-time, non-refundable, non-creditable payment of $15 million from Pfizer. Pfizer was obligated to reimburse the Company for costs incurred for research performed, up to a specified cap in the low double-digit millions. Upon the achievement of specified early development and regulatory milestones, Pfizer will be obligated to pay the Company up to $80 million in the aggregate. For other non-early stage development milestones Pfizer’s payment obligations to the Company depends upon whether the Company has exercised its co-funding and co-promotion option: 1) if it does not exercise the option, non-early stage development payments may total up to $165 million in aggregate, and 2) if it does exercise the option, non-early stage development payments may total up to $70 million in aggregate. Upon the achievement of specified sales milestones, Pfizer is also obligated to make tiered milestone payments of up to $235 million in aggregate. On a product-by-product basis, Pfizer will also be required to pay the Company high single-digit percentage royalties on annual net sales of each licensed product. If the Company exercises its co-promotion and co-funding option, royalty payments will exclude sales in the United States and the Company will share with Pfizer profits from sale of the relevant licensed product in the United States.

The initial transaction price of $27.0 million was allocated to the two performance obligations on a relative standalone value basis, with $25.6 million allocated to the license and $1.4 million allocated to the research activities, which were completed in 2020. The value attributable to the license was recognized upon delivery of the license to Pfizer and the value attributable to the research activities was recognized pro-rata based on the actual costs incurred by the Company compared to the total estimated costs of the research activities from the time of execution to the end of the research program.

There was no revenue recorded in connection with this agreement for the three months ended March 31, 2024 and 2023 because all development and sales milestones (variable consideration) were fully constrained.

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Commitments and Contingencies

3 Months Ended

Mar. 31, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. Commitments and Contingencies

Leases

In September 2021, the Company entered a non-cancelable three-year lease for certain office space in Solana Beach, California, with an option to renew for an additional three-year term. In January 2024, the Company executed a three-year extension to the lease with a new expiration date of October 31, 2027. The initial term of the lease started on November 1, 2021, and is serving as the Company's headquarters. Rent expense under this lease was $18,000 and $16,000 for the three months ended March 31, 2024 and 2023, respectively.

During the three months ended March 31, 2024 and 2023, the Company paid $19,000 and $14,000 in lease payments, respectively, which were included in operating activities in the statements of cash flows.

The following table summarizes supplemental balance sheet information related to leases as of March 31, 2024 and December 31, 2023 (in thousands):

	March 31, 2024		December 31, 2023
Assets:
Operating lease right-of-use assets	$	225	$	53
Total right-of-use assets		225		53
Liabilities
Operating lease liabilities, current		53		60
Operating lease liabilities, non-current		179		—
Total operating lease liabilities	$	232	$	60

As of March 31, 2024, the future minimum annual lease payments under the existing operating leases were as follows (in thousands, except for weighted-average remaining lease term and weighted-average discount rate):

Remainder of 2024	$	56
2025		77
2026		79
2027		68
Total remaining lease payments		280
Less: imputed interest		(48	)
Total operating lease liabilities		232
Less: current portion		(53	)
Long-term operating lease liabilities	$	179
Weighted-average remaining lease term (in years)		3.60
Weighted-average discount rate		11.5	%

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Employee Benefits

3 Months Ended

Mar. 31, 2024

Retirement Benefits [Abstract]

Employee Benefits

12. Employee Benefits

The Company has a defined contribution 401(k) plan available to eligible employees. Under the terms of the plan, employees may make voluntary contributions as a percent of compensation, limited to the maximum amount allowable under federal tax regulations. The Company, at its discretion, may make certain contributions to the 401(k) plan. Through March 31, 2024, the Company made no matching contributions.

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Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements as of March 31, 2024 and for the three months ended March 31, 2024 and 2023 have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act of 1933, as amended (the “Securities Act”). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. These unaudited financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows. The results for the three months ended March 31, 2024 are not necessarily indicative of the results expected for the full fiscal year or any subsequent interim period. The balance sheet at December 31, 2023 has been derived from the audited financial statements at that date but does not include all the disclosures required by GAAP for complete financial statements. Because all of the disclosures required by GAAP for complete financial

statements are not included herein, these unaudited financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2023 included in its Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 26, 2024.

Liquidity

Liquidity

The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of 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 the outcome of this uncertainty.

Management is required to perform a two-step analysis over its ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (step 2).

The Company has experienced net losses and negative cash flows from operating activities since its inception, aside from the years ended December 31, 2021 and December 31, 2020 when net income was realized as a result of a gain in fair value recognized associated with the earn-out liability and revenue in connection with the Research Collaboration and License Agreement with Pfizer, respectively. The Company has an accumulated deficit of $188.2 million at March 31, 2024. For the three months ended March 31, 2024, the Company used $7.3 million in cash for operations. At March 31, 2024, the Company had cash and cash equivalents and short-term investments of $25.4 million. The Company anticipates that its expenses will increase significantly in connection with its ongoing activities to support its research and development efforts, and it expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. Management has prepared cash flow forecasts which indicate that based on the Company’s expected operating losses and negative cash flows, there is substantial doubt about the Company’s ability to continue as a going concern within twelve months from the date that these financial statements for the three months ended March 31, 2024 are issued. The principal payments due under the Oxford Loans (as defined below), and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed above and the assessment that the material adverse change clause under the Oxford Loans is not within the Company’s control. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements.

The Company’s ability to continue as a going concern is dependent upon its ability to receive additional capital. Management intends to raise additional capital through equity offerings or other capital sources, including potential additional collaborations, licenses and other similar arrangements. Additionally, the Company may receive additional milestone payments from the Research Collaboration and License Agreement with Pfizer (described in Note 10), through the issuance of common stock under the equity purchase agreement with Lincoln Park Capital Fund, LLC (described in Note 8) or through the issuance of common stock under the at-the-market offering program (described in Note 8) with Cantor Fitzgerald & Co. However, the Company may not be able to secure additional financing in a timely manner or on favorable terms, if at all, and may not receive any milestone payments. Without additional capital, the Company may be forced to delay, scale back or eliminate some of its research and development activities, or other operations and potentially delay product development in an effort to provide sufficient funds to continue its operations, or may be required to pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of its stockholders.

Research and Development Costs

Research and Development Costs

Research and development expenses primarily consist of costs associated with the preclinical and clinical development of the Company’s product candidates. Research and development costs are expensed as incurred.

Clinical Trial Accruals and Preclinical Studies

Clinical Trial Accruals and Preclinical Studies

The Company records expenses resulting from our obligations under contracts with vendors and consultants, CROs and clinical sites in connection with conducting clinical trials and preclinical studies. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects clinical trial and preclinical study expenses in the financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial or preclinical study as measured by the timing of various aspects of the clinical trial, preclinical study, or related activities. The Company determines accrual estimates based on the underlying contracts, correspondence with clinical and other key personnel and third-party service providers as to the progress of the clinical trials, preclinical studies, or other services being conducted, and amounts invoiced or paid to date. During the course of a clinical trial or preclinical study, the Company adjusts the rate of expense recognition if actual results differ from estimates.

Public and Private Placement Warrants

Public and Private Placement Warrants

Upon completion of the Business Combination, the Company assumed public and private placement warrants that were issued by LWAC in connection with their initial public offering in January 2021 whereby holders of the public and private placement warrants are entitled to acquire common stock of the Company. The Company has concluded that the public warrants are equity-classified. Since the settlement value of the private placement warrants is dependent, in part, on who holds the warrants at the time of settlement, they are not considered indexed to the Company's stock and are therefore recorded as liabilities. Warrants classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying consolidated statements of operations and comprehensive income (loss). The Company estimates the fair value of these warrants using the Black-Scholes option pricing model.

Stock-Based Compensation Expense

Stock-Based Compensation Expense

Stock-based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model. The Company accounts for stock options granted to non-employees using the fair value approach.

The Black-Scholes option-pricing model requires the use of subjective assumptions, including the risk-free interest rate, the expected stock price volatility, the expected term of stock options, and the expected dividend yield. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The fair value of the underlying common stock used within the Black-Scholes option-pricing model is based on the closing price of common stock on the date of grant.

Comprehensive Loss

Comprehensive Loss

Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company presents comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss.

Cash, Cash Equivalents and Short-term Investments

Cash, Cash Equivalents and Short-term Investments

Cash and Cash Equivalents

The Company considers all highly liquid investments with insignificant interest rate risk and an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase.

Short-term Investments

Short-term investments consist of U.S. Treasury securities, classified as available-for-sale securities and have maturities of greater than three months but less than one year. The Company has classified all of its available-for-sale securities as current assets on the balance sheets because these are considered highly liquid securities and are available for use in current operations. The Company carries these securities at fair value and reports unrealized gains and losses as a separate component of accumulated other comprehensive loss. Amortization and accretion of any purchase premiums or discounts is included in interest income in the consolidated statements of operations and comprehensive loss.

Recent Accounting Pronouncements

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes, based on its preliminary assessment, that the impact of recently issued standards that are not yet effective will not have a material impact on their financial position or results of operations upon adoption.

Net Loss Per Share

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as

they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position.

For the three months ended March 31, 2024, all pre-funded warrants that were issued during the January 2024 Registered Direct Offering (as defined below) with an exercise price of $0.001, regardless of whether they were exercised as of March 31, 2024, were considered outstanding in the calculation of basic and diluted net loss per share (See Note 7 for details about pre-funded warrants).

Potentially dilutive securities as of March 31, 2024 and 2023 are as follows (in common stock equivalent shares):

	For the Three Months Ended March 31,
	2024		2023
Common stock warrants		2,257,426		—
Placement agent warrants		158,017		—
Public warrants		233,332		233,332
Private placement warrants		7,266		7,266
Earn-Out Shares		—		200,000
Unvested sponsor shares		12,000		12,000
Stock options outstanding		694,764		473,900
Total		3,362,805		926,498

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Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2024

Accounting Policies [Abstract]

Schedule of Potentially Dilutive Securities

Potentially dilutive securities as of March 31, 2024 and 2023 are as follows (in common stock equivalent shares):

	For the Three Months Ended March 31,
	2024		2023
Common stock warrants		2,257,426		—
Placement agent warrants		158,017		—
Public warrants		233,332		233,332
Private placement warrants		7,266		7,266
Earn-Out Shares		—		200,000
Unvested sponsor shares		12,000		12,000
Stock options outstanding		694,764		473,900
Total		3,362,805		926,498

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Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Summary of assets and liabilities measured at fair value on a recurring basis

The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy as of March 31, 2024 and December 31, 2023 (in thousands):

			Fair Value Measurements Using
	March 31,		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	2024		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	6,048	$	6,048	$	—	$	—
U.S. Treasury securities		9,460		—		9,460		—
Short-term investments:
U.S. Treasury securities		9,875		—		9,875		—
Total assets	$	25,383	$	6,048	$	19,335	$	—
Liabilities
Private placement warrant liability	$	40	$	—	$	—	$	40
Total liabilities	$	40	$	—	$	—	$	40

			Fair Value Measurements Using
	December 31,		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	2023		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	10,887	$	10,887	$	—	$	—
U.S. Treasury securities		3,988		—		3,988		—
Short-term investments:
U.S. Treasury securities		3,495		—		3,495		—
Total assets	$	18,370	$	10,887	$	7,483	$	—
Liabilities
Private placement warrant liability	$	40	$	—	$	—	$	40
Total liabilities	$	40	$	—	$	—	$	40

Summary of Short term Investment

The following tables summarize the Company’s short-term investments accounted for as available-for-sale securities as of March 31, 2024 and December 31, 2023 (in thousands):

				March 31, 2024
	Maturity	Amortized		Unrealized		Unrealized		Estimated
	(in years)	Cost		Gains		Losses		Fair Value
U.S. Treasury securities	1 year or less	$	9,875	$	—	$	—	$	9,875
		$	9,875	$	—	$	—	$	9,875

				December 31, 2023
	Maturity	Amortized		Unrealized		Unrealized		Estimated
	(in years)	Cost		Gains		Losses		Fair Value
U.S. Treasury securities	1 year or less	$	3,495	$	—	$	—	$	3,495
		$	3,495	$	—	$	—	$	3,495

Private Placement Warrants Liability [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Summary of fair value measurements inputs

The following key assumptions were used in determining the fair value of the private placement warrant liability valued using the Black-Scholes option pricing model as of March 31, 2024 and December 31, 2023:

	March 31, 2024			December 31, 2023
Common stock price	$	14.39		$	11.69
Expected volatility		125.0	%		125.0	%
Risk-free interest rate		4.5	%		4.1	%
Expected term (in years)		2.4			2.7
Expected dividend yield		—			—

Summary of change in fair value of derivative warrant liabilities

The following table presents activity for the private placement warrant liability measured at fair value using significant unobservable Level 3 inputs during the three months ended March 31, 2024 (in thousands):

	Private Placement Warrant Liability
Balance at December 31, 2023	$	40
Change in fair value		—
Balance at March 31, 2024	$	40

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Property and Equipment , net (Tables)

3 Months Ended

Mar. 31, 2024

Property, Plant and Equipment [Abstract]

Summary of Property and Equipment ,net

Property and equipment, net consists of the following (in thousands):

	March 31, 2024			December 31, 2023
Lab equipment	$	108		$	30
Computer and office equipment		154			154
Furniture and fixtures		78			78
Leasehold improvements		188			188
Construction in process		14			14
		542			464
Less accumulated depreciation and amortization		(352	)		(324	)
	$	190		$	140

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Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consist of the following (in thousands):

	March 31, 2024		December 31, 2023
Employee compensation	$	978	$	1,587
Research and development		2,461		1,036
Professional and outside services		131		75
Interest		217		223
	$	3,787	$	2,921

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Term Loans (Tables)

3 Months Ended

Mar. 31, 2024

Notes and Loans Payable, by Type, Current and Noncurrent [Abstract]

Schedule of Principal Future Payments of Term Loans

Based on the outstanding principal amounts for the Company’s Term A Loans, the following table sets forth by year the Company’s required future principal payments as of March 31, 2024 (in thousands):

As of March 31, 2024
Remainder of 2024	$	5,000
2025		6,667
2026		6,667
2027		1,110
Required future principal payments	$	19,444
Unamortized debt discount		(528	)
Current term loans, net as of March 31, 2024	$	18,916

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Warrants (Tables)

3 Months Ended

Mar. 31, 2024

Class of Warrant or Right [Table]

Summary of Public and private placement warrants outstanding.

The following table summarizes the number of outstanding public warrants and private placement warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023		Exercise Price		Expiration Date
Public warrants		233,332		233,332	$	287.50	August 24, 2026
Private placement warrants		7,266		7,266	$	287.50	August 24, 2026

Warrant [Member]

Class of Warrant or Right [Table]

Summary of Public and private placement warrants outstanding.

The common stock warrants, placement agent warrants and pre-funded warrants are equity-classified. The following table summarizes the number of outstanding common stock warrants, placement agent warrants and pre-funded warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023		Exercise Price		Expiration Date
May 2023 Common Stock Warrants		458,015		458,015	$	13.25	November 30, 2028
May 2023 Placement Agent Warrants		32,060		32,060	$	20.47	May 26, 2028
June 2023 Common Stock Warrants		310,577		310,577	$	25.00	December 8, 2028
June 2023 Placement Agent Warrants		21,739		21,739	$	35.1575	June 6, 2028
January 2024 Pre-funded Warrants		653,000		—	$	0.001	N/A
January 2024 Common Stock Warrants		1,488,834		—	$	9.95	July 29, 2027
January 2024 Placement Agent Warrants		104,218		—	$	12.5938	July 29, 2027

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Preferred Stock and Stockholders' Deficit (Tables)

3 Months Ended

Mar. 31, 2024

Equity [Abstract]

Summary of option activity under the company's plans

A summary of the Company’s stock option activity under the plans is as follows (in thousands, except share and per share amounts and years):

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2023		480,875		$	51.67		7.3	$	—
Granted		231,800			11.32		9.9
Cancelled or forfeited		(17,911	)		13.53		3.9
Outstanding at March 31, 2024		694,764		$	39.19		7.9	$	1,039
Vested and exercisable at March 31, 2024		325,122		$	56.29		6.3	$	151

Schedule of assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants.

The assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows:

	Three Months Ended March 31,
	2024	2023
Risk-free interest rate	4.3%	3.6% - 4.1%
Expected volatility	84% - 85%	84%
Expected term (in years)	5.3 - 6.0	5.3 - 6.1
Expected dividend yield	0%	0%

Schedule of Common Stock, Reserved for Future Issuance

Common stock reserved for future issuance consists of the following as of March 31, 2024 and December 31, 2023:

	March 31, 2024		December 31, 2023
Stock options issued and outstanding		694,764		480,875
Public warrants issued and outstanding		233,332		233,332
Private placement warrants issued and outstanding		7,266		7,266
Common stock warrants issued and outstanding		2,257,426		768,592
Placement agent warrants issued and outstanding		158,017		53,799
Pre-funded warrants		653,000		—
Unvested sponsor shares		12,000		12,000
Authorized for future stock awards or option grants		32,293		96,449
Authorized for future issuances under the ESPP		89,090		59,144
Total		4,137,188		1,711,457

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Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2024

Commitments and Contingencies Disclosure [Abstract]

Schedule of Supplemental Balance sheet Information related to Leases

The following table summarizes supplemental balance sheet information related to leases as of March 31, 2024 and December 31, 2023 (in thousands):

	March 31, 2024		December 31, 2023
Assets:
Operating lease right-of-use assets	$	225	$	53
Total right-of-use assets		225		53
Liabilities
Operating lease liabilities, current		53		60
Operating lease liabilities, non-current		179		—
Total operating lease liabilities	$	232	$	60

Schedule of Future Minimum Rental Payments for Operating Leases

As of March 31, 2024, the future minimum annual lease payments under the existing operating leases were as follows (in thousands, except for weighted-average remaining lease term and weighted-average discount rate):

Remainder of 2024	$	56
2025		77
2026		79
2027		68
Total remaining lease payments		280
Less: imputed interest		(48	)
Total operating lease liabilities		232
Less: current portion		(53	)
Long-term operating lease liabilities	$	179
Weighted-average remaining lease term (in years)		3.60
Weighted-average discount rate		11.5	%

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Organization and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares shares	Jan. 09, 2024 $ / shares	Dec. 31, 2023 USD ($) $ / shares
Subsidiary Sale Of Stock [Line Items]
Place of incorporation	DE
Accumulated deficit	$ 188,211		$ 179,377
Cash from operation	7,300
Cash & Cash Equivalents in Securities	$ 25,400
Date of incorporation	Oct. 02, 2020
Common stock price per share | $ / shares	$ 0.0001		$ 0.0001
Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Common stock price per share | $ / shares	$ 0.0001	$ 0.0001
Maximum [Member] | Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Shares issued | shares	1,000,000,000
Minimum [Member] | Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Shares issued | shares	40,000,000
Locust Walk Acquisition Corp [Member]
Subsidiary Sale Of Stock [Line Items]
Conversion of outstanding common and preferred shares into common shares	0.09657

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Summary of Significant Accounting Policies - Additional Information (Detail)	Mar. 31, 2024 $ / shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Exercise price of warrants	$ 0.001

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Summary of Significant Accounting Policies - Schedule of basic and diluted net income (loss) per share (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Basic Net Income (Loss) per share
Weighted average common shares outstanding - basic	4,081,580	1,680,032
Net loss per share - Basic	$ (2.16)	$ (5.96)
Diluted Net income (Loss) per share
Weighted average common shares outstanding - basic	4,081,580	1,680,032
Weighted average common shares outstanding - diluted	4,081,580	1,680,032
Net loss per share - diluted	$ (2.16)	$ (5.96)

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Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities (Detail) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	3,362,805	926,498
Common Stock Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	2,257,426	0
Placement agent warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	158,017	0
Public warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	233,332	233,332
Private Placement [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	7,266	7,266
Earn-Out Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	0	200,000
Unvested sponsor shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	12,000	12,000
Stock Options Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	694,764	473,900

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Fair Value Measurementsn - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash & Cash Equivalents in Securities	$ 25,400
Short-term investments	9,875	$ 3,495
Fair Value, Inputs, Level 1, 2 and 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, net derivative asset (liability) measured on recurring basis, unobservable inputs reconciliation, transfers, net	0	0
Investments in money market fund	6,000	10,900
Marketable Securities	19,300	7,500
Interest Receivable	17,000	52,000
Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash & Cash Equivalents in Securities	9,500	4,000
Short-term investments	$ 9,900	$ 3,500

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Fair Value Measurements - Summary of Assets And Liabilities Measured At Fair Value On Recurring Basis (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Total assets	$ 25,383	$ 18,370
Liabilities
Total liabilities	40	40
US Treasury Securities [Member]
Assets
U.S. Treasury securities	9,460	3,988
Private Placement Warrant Liability
Liabilities
Warrant liability	40	40
Fair Value Inputs Level 1
Assets
Total assets	6,048	10,887
Liabilities
Total liabilities	0	0
Fair Value Inputs Level 2
Assets
Total assets	19,335	7,483
Liabilities
Total liabilities	0	0
Fair Value Inputs Level 2 | US Treasury Securities [Member]
Assets
U.S. Treasury securities	9,460	3,988
Fair Value Inputs Level 3
Assets
Total assets	0	0
Liabilities
Total liabilities	40	40
Fair Value Inputs Level 3 | Private Placement Warrant Liability
Liabilities
Warrant liability	40	40
Money Market Funds
Assets
Money market funds	6,048	10,887
Money Market Funds | Fair Value Inputs Level 1
Assets
Money market funds	6,048	10,887
Short-Term Investments [Member] | US Treasury Securities [Member]
Assets
U.S. Treasury securities	9,875	3,495
Short-Term Investments [Member] | Fair Value Inputs Level 2 | US Treasury Securities [Member]
Assets
U.S. Treasury securities	$ 9,875	$ 3,495

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Fair Value Measurements - Summary of Short term Investment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 9,875	$ 3,495
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	$ 9,875	$ 3,495
U.S. Treasury Securities
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year	1 year
Amortized Cost	$ 9,875	$ 3,495
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	$ 9,875	$ 3,495

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Fair Value Measurements - Summary of change in fair value of preferred stock warrant liability (Detail) - Series C Preferred Stock Warrant Liability [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, Beginning Balance	$ 40
Change in fair value	0
Fair value, Ending Balance	$ 40

XML

Fair Value Measurements - Summary of fair value measurements inputs of private placement warrant liability (Detail) - Private Placement Warrant Liability	Mar. 31, 2024 USD ($) yr	Dec. 31, 2023 yr USD ($)
Common Stock Price
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | $	14.39	11.69
Expected volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	125	125
Risk-free interest rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	4.5	4.1
Expected term (in years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | yr	2.4	2.7
Expected dividend yield
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	0	0

XML

Property and Equipment, net - Summary of Property and Equipment, net (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 542	$ 464
Less accumulated depreciation and amortization	(352)	(324)
Property and Equipment, Net	190	140
Lab Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	108	30
Computer And Office Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	154	154
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	78	78
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	188	188
Construction In Progress
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 14	$ 14

XML

Property and Equipment, net - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 28,000	$ 28,000

XML

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Employee compensation	$ 978	$ 1,587
Research and development	2,461	1,036
Professional and outside services	131	75
Interest	217	223
Accrued Liabilities, Current	$ 3,787	$ 2,921

XML

Term Loans - Additional Information (Detail) $ / shares in Units, $ in Thousands		3 Months Ended
	Feb. 22, 2022 USD ($)	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($)	Mar. 31, 2021 USD ($) Tranche	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Exercise price of warrants | $ / shares		$ 0.001
Outstanding principal, Term loans		$ 18,916
Extended cut off date before which the interest on term loan shall be paid	Mar. 01, 2024
Long term debt net of unamortized debt discounts		$ 19,444
Loan and Security Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Number of tranches | Tranche				2
Debt instrument, face amount				$ 30,000
Number of days within which a portion of term loan will be available subject to achievement of milestone	45 days
Long term debt variable interest rate percentage		7.70%
Loan and Security Agreement [Member] | Prime Rate [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt instrument variable interest rate spread		4.45%
Loan and Security Agreement [Member] | Warrants To Purchase Series C Redeemable Convertible Stock | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Exercise price of warrants | $ / shares		$ 133.25
Number of shares subject to each warrant | shares		1,503
Loan and Security Agreement [Member] | Debt Instrument, Term Loan A [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt Instrument, Discount		$ 1,600
Outstanding principal, Term loans		19,400		$ 20,000	$ 20,000
Amortization of debt discount		700	$ 700
Extended maturity of Term A Loans, Description	In connection with the amendment, the maturity of the Term A Loans was extended from March 18, 2026 to February 1, 2027.
Term loan final payment as a percentage of the amount funded				5.50%
Long term debt net of unamortized debt discounts		$ 18,900		$ 20,000	$ 19,400
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member]
Debt Instrument [Line Items]
Term Loans Additional	$ 10,000
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member] | Less Than One Year From The Date Of Loan Agreement [Member]
Debt Instrument [Line Items]
Loan initiation date	Jun. 30, 2023
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				$ 10,000

XML

Term Loans - Schedule of Principal Future Payments of Term Loans (Detail) $ in Thousands	Mar. 31, 2024 USD ($)
Notes and Loans Payable, by Type, Current and Noncurrent [Abstract]
Remainder of 2024	$ 5,000
2025	6,667
2026	6,667
2027	1,110
Required future principal payments	19,444
Unamortized debt discount	(528)
Current term loans, net as of March 31, 2024	$ 18,916

XML

Warrants - Additional Information (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.001
Public Warrants and Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise price of warrants	287.5
Class of warrants, redemption price per unit	$ 0.25
Class of warrants, redemption notice period	30 days
Share price	$ 450
Warrants and rights outstanding, term	5 years
Number of consecutive trading days for determining share price	20 days
Number of trading days to determine share price	30 days
May 2023 Registered Direct Offering
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.025
Class of Warrant or Right, Outstanding	270,015
Pre-funded warrants with a purchase price	$ 16.35
May 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 20.47
Class of Warrant or Right, Outstanding	32,060	32,060
Expiration date	May 26, 2028
May 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 13.25
Class of Warrant or Right, Outstanding	458,015	458,015
Expiration date	Nov. 30, 2028
June 2023 Registered Direct Offering
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.025
Class of Warrant or Right, Outstanding	72,578
Pre-funded warrants with a purchase price	$ 28.1
June 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 25
Class of Warrant or Right, Outstanding	310,577	310,577
Expiration date	Dec. 08, 2028
June 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 35.1575
Class of Warrant or Right, Outstanding	21,739	21,739
Expiration date	Jun. 06, 2028
January 2024 Registered Direct Offering
Class of Warrant or Right [Line Items]
Warrants exercise	497,834
Exercise price of warrants	$ 0.001
Class of Warrant or Right, Outstanding	1,150,834
Pre-funded warrants with a purchase price	$ 10.074
January Two Thousand Twenty Four Pre-funded Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.001
Class of Warrant or Right, Outstanding	653,000	0
January 2024 Common Stock Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 9.95
Class of Warrant or Right, Outstanding	1,488,834	0
Expiration date	Jul. 29, 2027
January 2024 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 12.5938
Class of Warrant or Right, Outstanding	104,218	0
Expiration date	Jul. 29, 2027

XML

Warrants - Schedule of Public and private placement warrants outstanding (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.001
Public Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	233,332	233,332
Exercise price of warrants	$ 287.5
Expiration date	Aug. 24, 2026
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	7,266	7,266
Exercise price of warrants	$ 287.5
Expiration date	Aug. 24, 2026
May 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	458,015	458,015
Exercise price of warrants	$ 13.25
Expiration date	Nov. 30, 2028
May 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	32,060	32,060
Exercise price of warrants	$ 20.47
Expiration date	May 26, 2028
June 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	310,577	310,577
Exercise price of warrants	$ 25
Expiration date	Dec. 08, 2028
June 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	21,739	21,739
Exercise price of warrants	$ 35.1575
Expiration date	Jun. 06, 2028
January 2024 Pre-funded Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	653,000	0
Exercise price of warrants	$ 0.001
January 2024 Common Stock Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	1,488,834	0
Exercise price of warrants	$ 9.95
Expiration date	Jul. 29, 2027
January 2024 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	104,218	0
Exercise price of warrants	$ 12.5938
Expiration date	Jul. 29, 2027

XML

Equity Purchase Agreement (Additional Information) (Details) $ in Millions	Jan. 24, 2022 USD ($)
Purchase Agreement [Member]
Defined Benefit Plan Disclosure [Line Items]
Other expense relating to the commitment fee	$ 0.8

XML

Preferred Stock and Stockholders' Equity - Additional Information (Detail)			3 Months Ended
	Sep. 30, 2022 USD ($)	Jan. 24, 2022 USD ($) $ / shares shares	Mar. 31, 2024 USD ($) TradingDays $ / shares shares	Mar. 31, 2023 USD ($) shares	Dec. 31, 2023 USD ($) $ / shares shares	Aug. 24, 2021 shares
Class Of Stock [Line Items]
Preferred Stock, Shares authorized | shares			100,000,000		100,000,000
Preferred stock, par value | $ / shares			$ 0.0001		$ 0.0001
Common Stock Value			$ 0		$ 0
Proceeds from exercise of common stock options and prefunded warrants			$ 1,000	$ 0
Preferred stock, shares outstanding | shares			0		0
Stock options outstanding | shares			694,764		480,875
Common stock, shares issued | shares			3,914,309		2,994,679
Number of Option Outstanding,Granted | shares			231,800
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit | $ / shares			$ 100
Increase in reserved shares, percentage | $ / shares			$ 110
No share purchases under the Purchase Agreement | shares			0	0
Fair value of vested option			$ 1,000,000
Share-based Payment Arrangement, Expense			1,000,000	$ 1,200,000
Unrecognized compensation cost related to outstanding employee options			$ 5,600,000
Expected term (in years)			2 years 9 months 18 days
Maximum [Member]
Class Of Stock [Line Items]
Expected term (in years)			6 years	6 years 1 month 6 days
Minimum [Member]
Class Of Stock [Line Items]
Expected term (in years)			5 years 3 months 18 days	5 years 3 months 18 days
Holder of More Than 10% [Member]
Class Of Stock [Line Items]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit | $ / shares			$ 10
Purchase Agreement [Member]
Class Of Stock [Line Items]
Other expense relating to the commitment fee		$ 800,000
Lincoln Park [Member]
Class Of Stock [Line Items]
Purchase Agreement		36 months
Initial Purchase Amount		$ 3,000,000
Initial purchase number of shares | shares		22,304
Shares issued, commitment shares | shares		5,717
Lincoln Park [Member] | Maximum [Member]
Class Of Stock [Line Items]
Available for sales of common shares under the facility		$ 50,000,000
Lincoln Park [Member] | Regular Purchase [Member]
Class Of Stock [Line Items]
Trading volume percentage		25.00%
Percentage of common shares outstanding prior to the execution of purchase agreement		97.00%
Sponsor Shares [Member]
Class Of Stock [Line Items]
Stock options outstanding | shares			162,250
Share based compensation options vesting shares | shares			12,000
Sponsor Shares [Member] | Maximum [Member]
Class Of Stock [Line Items]
Trading days | TradingDays			30
Sponsor Shares [Member] | Minimum [Member]
Class Of Stock [Line Items]
Trading days | TradingDays			20
Atm Offering Program Member
Class Of Stock [Line Items]
Payments Of Commission Percentage	3.00%
Preferred Units, Offering Costs	$ 6,800,000
Proceeds from exercise of common stock options and prefunded warrants			$ 900,000
Shares Issued Price Per Share | $ / shares			$ 11.07
Common stock, shares issued | shares			83,948
Temporary equity underwriting discounts, commissions and fees			$ 100,000
Atm Offering Program Member | Maximum [Member]
Class Of Stock [Line Items]
Common Stock Value	$ 50,000,000
2013, Equity Incentive Plan
Class Of Stock [Line Items]
Stock options outstanding | shares			130,617
June Two Thousand Twenty Three Registered Direct Offering [Member]
Class Of Stock [Line Items]
Amortization Of Sales Commissions			$ 900,000
Net Proceed			7,800,000
Proceeds from exercise of common stock options and prefunded warrants			$ 8,700,000
Shares Issued Price Per Share | $ / shares			$ 28.125
Common stock, shares issued | shares			238,000
January Two Thousand Twenty Four Registered Direct Offering Member [Member]
Class Of Stock [Line Items]
Amortization Of Sales Commissions			$ 1,400,000
Net Proceed			13,600,000
Proceeds from exercise of common stock options and prefunded warrants			$ 15,000,000
Shares Issued Price Per Share | $ / shares			$ 10.075
Common stock, shares issued | shares			338,000
2021, Equity Incentive Plan
Class Of Stock [Line Items]
Shares authorized | shares			596,440
Shares purchased for award | shares			607,306
Number of shares reserved for future issuance | shares			32,293
Shares grants | shares			32,293
2021 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Shares fair market value percentage						85.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Increase in Reserved Shares						1.00%
Number of shares reserved for future issuance | shares			89,090			35,200
Shares grants | shares			89,090			35,200
2021 Employee Stock Purchase Plan [Member] | Maximum [Member]
Class Of Stock [Line Items]
Number of shares reserved for future issuance | shares						600,000
Shares grants | shares						600,000
May Two Thousand Twenty Three Register Direct Offering [Member]
Class Of Stock [Line Items]
Amortization Of Sales Commissions			$ 800
Net Proceed			6,700,000
Proceeds from exercise of common stock options and prefunded warrants			$ 7,500,000
Shares Issued Price Per Share | $ / shares			$ 16.375
Common stock, shares issued | shares			188,000
Common Stock [Member] | Lincoln Park [Member]
Class Of Stock [Line Items]
Ownership percentage		4.99%
Common Stock [Member] | Lincoln Park [Member] | Maximum [Member]
Class Of Stock [Line Items]
Purchase shares | shares		1,200
Common Stock [Member] | Lincoln Park [Member] | Purchase Agreement [Member]
Class Of Stock [Line Items]
Price per share | $ / shares		$ 160.5
Percentage of common shares outstanding prior to the execution of purchase agreement		19.99%
Aggregate number of common shares | shares		325,357
Common Stock [Member] | Lincoln Park [Member] | Regular Purchase [Member]
Class Of Stock [Line Items]
Regular Purchase, Description		The Fully Adjusted Regular Purchase Share Limit may be increased as follows: to up to 2,000 shares if the closing price is not below $125.00, and up to 3,000 shares if the closing price is not below $250.00.
Committed obligation amount		$ 500,000,000
Common Stock [Member] | Lincoln Park [Member] | Regular Purchase [Member] | Maximum [Member]
Class Of Stock [Line Items]
Purchase shares | shares			1,200
Common Stock [Member] | Sponsor Shares [Member]
Class Of Stock [Line Items]
Shares Issued Price Per Share | $ / shares			$ 375
Common Stock [Member] | 2021 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Stock Issued During Period, Shares, Employee Stock Purchase Plans | shares			0	0
Employee Option [Member]
Class Of Stock [Line Items]
Weighted-average grant date fair value | $ / shares			$ 8.27
Non-Employee Option [Member]
Class Of Stock [Line Items]
Weighted-average grant date fair value | $ / shares			$ 8.27
Unrecognized compensation cost related to outstanding employee options			$ 600,000
Expected term (in years)			1 year
H.C. Wainwright & Co [Member] | January Two Thousand Twenty Four Registered Direct Offering Member [Member]
Class Of Stock [Line Items]
Costs and Expenses, Total			$ 50,000,000
H.C. Wainwright & Co [Member] | Private Placement [Member] | June Two Thousand Twenty Three Registered Direct Offering [Member]
Class Of Stock [Line Items]
gross proceed			7.00%
Managemengt fees percentage			1.00%
Costs and Expenses, Total			$ 50,000,000
clearing fees			$ 15,950,000
H.C. Wainwright & Co [Member] | Private Placement [Member] | January Two Thousand Twenty Four Registered Direct Offering Member [Member]
Class Of Stock [Line Items]
gross proceed			7.00%
Managemengt fees percentage			1.00%
Costs and Expenses, Total			$ 25,000,000
clearing fees			$ 15,950,000
H.C. Wainwright & Co [Member] | Private Placement [Member] | May Two Thousand Twenty Three Register Direct Offering [Member]
Class Of Stock [Line Items]
gross proceed			7.00%
Managemengt fees percentage			1.00%
Costs and Expenses, Total			$ 75,000,000
clearing fees			$ 15,950,000

XML

Preferred Stock and Stockholders' Equity - Summary of Option Activity Under the Company's Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Equity [Abstract]
Number of Option Outstanding,Beginning balance	480,875
Number of Option Outstanding,Granted	231,800
Number of Option Outstanding, Cancelled or forfeited	(17,911)
Number of Option Outstanding,Ending balance	694,764	480,875
Number of Option Exercisable	325,122
Weighted Average Exercise Price,Beginning balance	$ 51.67
Weighted Average Exercise Price,Granted	11.32
Weighted average exercise price,Cancelled	13.53
Weighted Average Exercise Price,Ending balance	39.19	$ 51.67
Weighted Average Exercise Price,Exercisable	$ 56.29
Weighted- Average Remaining Contractual Term,Beginning balance	7 years 10 months 24 days	7 years 3 months 18 days
Weighted- Average Remaining Contractual Term,Granted	9 years 10 months 24 days
Weighted- Average Remaining Contractual Term,Cancelled	3 years 10 months 24 days
Weighted- Average Remaining Contractual Term, Ending balance	7 years 10 months 24 days	7 years 3 months 18 days
Weighted- Average Remaining Contractual Term,Exercisable	6 years 3 months 18 days
Aggregate Intrinsic Value,Beginning balance	$ 0
Aggregate Intrinsic Value,Ending balance	1,039	$ 0
Aggregate Intrinsic Value,Exercisable	$ 151

XML

Preferred Stock and Stockholders' Equity - Schedule of assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants (Detail)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	4.30%
Expected volatility		84.00%
Expected term (in years)	2 years 9 months 18 days
Expected dividend yield	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate		3.60%
Expected volatility	84.00%
Expected term (in years)	5 years 3 months 18 days	5 years 3 months 18 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate		4.10%
Expected volatility	85.00%
Expected term (in years)	6 years	6 years 1 month 6 days

XML

Preferred Stock and Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Class Of Stock [Line Items]
Stock options issued and outstanding	694,764	480,875
Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants	$ 2,257,426	$ 768,592
Placement agent warrants issued and outstanding	$ 158,017	$ 53,799
Pre-funded Warrants	653,000	0
Unvested Shares Held By Sponsors	12,000	12,000
Authorized for future stock awards or option grants	32,293	96,449
Authorized for future issuances under the ESPP	89,090	59,144
Total	4,137,188	1,711,457
Public Warrants Issued and Outstanding
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding	233,332	233,332
Private Placement Warrants Issued and Outstanding
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding	7,266	7,266
Common Stock [Member]
Class Of Stock [Line Items]
Stock options issued and outstanding	694,764	480,875

XML

Earn-Out Shares - Additional Information (Detail) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Common stock price per share	$ 0.0001	$ 0.0001
Common stock, shares issued	3,914,309	2,994,679

XML

Earn-Out Shares - Summary of Activity for Earn-Out Liability (Detail) - Series C Preferred Stock Warrant Liability [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	$ 40
Change in fair value	0
Fair value, Ending Balance	$ 40

XML

License Agreements - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Aug. 31, 2021	Jul. 31, 2021
License Agreement Disclosure [Line Items]
Research and development	$ 5,306,000	$ 6,609,000
Regents of the University of California [Member]
License Agreement Disclosure [Line Items]
Payable in connection with the closing of the merger agreement			$ 1,000,000
Research and development	$ 15,000	$ 15,000
Regents of the University of California [Member] | Amendment to the License Agreement [Member]
License Agreement Disclosure [Line Items]
Payable in connection with the closing of the merger agreement				$ 1,000,000
Regents of the University of California [Member] | Amendment to the License Agreement [Member] | Certain Clinical and Regulatory Milestones [Member]
License Agreement Disclosure [Line Items]
Remaining milestone payments payable				$ 375,000

XML

Research Collaboration and License Agreement - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Dec. 31, 2019	Mar. 31, 2024	Mar. 31, 2023
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		$ 27,000
Revenue from contract with customer excluding assessed tax		0	$ 0
Based on License [Member]
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		25,600
Based on Research Activities [Member]
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		1,400
Early Development and Regulatory Milestones [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		80,000
Non Early Stage Development Milestones [Member] | Non Exercise of Co-Funding And Co-Promotion Option [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		165,000
Non Early Stage Development Milestones [Member] | Exercise of Co-Funding And Co-Promotion Option [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		70,000
Specified Sales Based Milestones [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		$ 235,000
Pfizer [Member]
Research Collaboration And License Agreement [Line Items]
Upfront payment received	$ 15,000

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Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2021
Lessee, Lease, Description [Line Items]
Operating lease, payments	$ 19,000	$ 14,000
Lease term			3 years
Building [Member]
Lessee, Lease, Description [Line Items]
Operating lease, cost	$ 18,000	$ 16,000

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Commitments and Contingencies - Schedule of Supplemental Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Operating lease right-of-use assets	$ 225	$ 53
Total right-of-use assets	225	53
Liabilities
Operating lease liabilities, current	53	60
Long-term operating lease liabilities	179	0
Total operating lease liabilities	$ 232	$ 60

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Commitments and Contingencies - Schedule of Future Minimum Rental Payments for Operating Leases (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2024	$ 56
2025	77
2026	79
2027	68
Total remaining lease payments	280
Less: imputed interest	(48)
Total operating lease liabilities	232	$ 60
Less: current portion	(53)
Long-term operating lease liabilities	$ 179	$ 0
Weighted-average remaining lease term (in years)	3 years 7 months 6 days
Weighted-average discount rate	11.50%

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Employee Benefits (Additional Information) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Retirement Benefits [Abstract]
Defined Contribution Plan, Cost	$ 0

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Subsequent Events - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Mar. 31, 2024	Dec. 31, 2023
Subsequent Event [Line Items]
Common Stock, Value, Issued		$ 0	$ 0
Atm Offering Program Member
Subsequent Event [Line Items]
Payments Of Commission Percentage	3.00%
Maximum | Atm Offering Program Member
Subsequent Event [Line Items]
Common Stock, Value, Issued	$ 50,000