10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 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 September 30, 2022

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: 001-37449

ALPINE IMMUNE SCIENCES, INC.

(Exact name of registrant as specified in its charter)

Delaware	20-8969493
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
188 East Blaine Street, Suite 200

Seattle, WA  98102

(206) 788-4545

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

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, par value $0.001 per share	ALPN	The Nasdaq Stock Market LLC

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, a 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 November 8, 2022, the registrant had 45,914,433 shares of common stock, $0.001 par value per share, outstanding.

ALPINE IMMUNE SCIENCES, INC.

FORM 10-Q

FOR THE QUARTER ENDED SEPTEMBER 30, 2022

TABLE OF CONTENTS

PART I. FINANCIAL INFORMATION
Item 1.	Financial Statements (unaudited)	1
	Condensed Consolidated Balance Sheets	1
	Condensed Consolidated Statements of Operations and Comprehensive Income (Loss)	2
	Condensed Consolidated Statements of Stockholders’ Equity	3
	Condensed Consolidated Statements of Cash Flows	4
	Notes to Condensed Consolidated Financial Statements	5
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	14
Item 3.	Quantitative and Qualitative Disclosures about Market Risk	26
Item 4.	Controls and Procedures	26
PART II. OTHER INFORMATION
Item 1.	Legal Proceedings	28
Item 1A.	Risk Factors	28
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	71
Item 3.	Defaults Upon Senior Securities	71
Item 4.	Mine Safety Disclosure	71
Item 5.	Other Information	71
Item 6.	Exhibits	72
	Signatures

In this report, unless otherwise stated or as the context otherwise requires, references to “Alpine,” “the Company,” “we,” “us,” “our” and similar references refer to Alpine Immune Sciences, Inc. “TIP” and “SIP are registered trademarks and the Company logo is a trademark of Alpine Immune Sciences, Inc. All rights reserved. This report also contains registered marks, trademarks, and trade names of other companies. All other trademarks, registered marks, and trade names appearing in this report are the property of their respective holders. 

SUMMARY RISK FACTORS

Our business is subject to numerous risks and uncertainties, including those highlighted in the section of this report captioned “Risk Factors.” The following is a summary of the principal risks we face:

•Our approach to the discovery and development of innovative therapeutic treatments based on our technology is unproven and may not result in marketable products.

•Our therapeutic candidates are in early stages of development and may fail in development or suffer delays that materially and adversely affect their commercial viability.

•Product development involves a lengthy and expensive process with an uncertain outcome, and results of earlier preclinical and clinical trials may not be predictive of future clinical trial results.

•We face competition from entities that have developed or may develop therapeutic candidates for our target disease indications, including companies developing novel treatments and technology platforms based on modalities and technology similar to us.

•To date, our revenue has been primarily derived from our collaboration agreements, and our success will be dependent, in part, on our collaborators’ efforts to develop our therapeutic candidates.

•If third parties on which we depend to conduct our clinical or preclinical studies, or any future clinical trials, do not perform as expected, fail to satisfy regulatory or legal requirements, or miss expected deadlines, our development program could be delayed, which may result in materially adverse effects on our business, financial condition, results of operations, and prospects.

•We may not successfully engage in strategic transactions, including any additional collaborations we seek, which could adversely affect our ability to develop and commercialize therapeutic candidates, impact our cash position, increase our expenses, and present significant distractions to our management.

•If any of our therapeutic candidates are approved for marketing and commercialization and we are unable to develop sales, marketing and distribution capabilities on our own or enter into agreements with third parties to perform these functions on acceptable terms, we may be unable to successfully commercialize any such future products.

•The COVID-19 coronavirus could adversely impact our business, including our clinical trials.

•We depend on our information technology systems and any failure of these systems could harm our business.

•We will need to raise substantial additional funds to advance development of our therapeutic candidates, and we cannot guarantee we will have sufficient funds available in the future to develop and commercialize our current or future therapeutic candidates.

•We are an early-stage biopharmaceutical company with a history of losses, we expect to continue to incur significant loses for the foreseeable future, we may never achieve or maintain profitability, and we have a limited operating history that may make it difficult for investors to evaluate the potential success of our business.

•If we are not able to obtain and enforce patent protection for our technology, including therapeutic candidates, therapeutic products, and platform technology, development of our therapeutic candidates and platform, and commercialization of our therapeutic products may be materially and adversely affected.

•We may license patent rights from third-party owners or licensees. If such owners or licensees do not properly or successfully obtain, maintain or enforce the patents underlying such licenses, or if they retain or license to others any competing rights, our competitive position and business prospects may be materially and adversely affected.

•We or our licensors, collaborators, or any future strategic partners may become subject to third-party claims or litigation alleging infringement of patents or other proprietary rights or seeking to invalidate patents or other proprietary rights, and we may need to resort to litigation to protect or enforce our patents or other proprietary rights, all of which could be costly, time consuming, delay or prevent the development of our therapeutic candidates and commercialization of our therapeutic products, or put our patents and other proprietary rights at risk.

•If we fail to comply with our obligations under any license, collaboration, or other agreements, we may be required to pay damages and could lose intellectual property rights necessary for developing and protecting our technology, including our platform technology, therapeutic candidates, and therapeutic products, or we could lose

certain rights to grant sublicenses, either of which could have a material adverse effect on our results of operations and business prospects.

•We may be unable to obtain U.S. or foreign regulatory approval and, as a result, may be unable to commercialize our therapeutic candidates.

•The healthcare industry is heavily regulated in the U.S. at the federal, state, and local levels, and our failure to comply with applicable requirements may subject us to penalties and negatively affect our financial condition.

•Our stock price may be volatile, and an active, liquid, and orderly trading market may not develop for our common stock. As a result, stockholders may not be able to resell shares at or above their purchase price.

•Our officers and directors, and their respective affiliates, have a controlling influence over our business affairs and may make business decisions with which stockholders disagree and which may adversely affect the value of their investment.

Our Risk Factors are not guarantees that no such conditions exist as of the date of this report and should not be interpreted as an affirmative statement that such risks or conditions have not materialized, in whole or in part.

PART I. FINANCIAL INFORMATION

Item 1. Financial Statements (unaudited).

ALPINE IMMUNE SCIENCES, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands, except share and per share amounts)

	September 30, 2022		December 31, 2021
Assets	(unaudited)
Current assets:
Cash and cash equivalents	$	126,625	$	67,907
Short-term investments	122,237		94,396
Accounts receivable	382		25,000
Prepaid expenses and other current assets	3,995		4,710
Total current assets	253,239		192,013
Restricted cash, noncurrent	254		254
Property and equipment, net	1,608		1,716
Operating lease, right-of-use asset	8,381		8,837
Long-term investments	28,016		52,866
Deferred tax asset	101		214
Total assets	$	291,599	$	255,900
Liabilities and stockholders’ equity
Current liabilities:
Accounts payable	$	3,240	$	3,349
Accrued liabilities	13,744		9,417
Deferred revenue, current	46,210		51,773
Operating lease liability, current	718		617
Current portion of long-term debt	4,547		4,622
Total current liabilities	68,459		69,778
Deferred revenue, noncurrent	30,803		50,830
Operating lease liability, noncurrent	10,328		11,009
Long-term debt	—		3,380
Total liabilities	109,590		134,997
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized at September 30, 2022 and December 31, 2021; zero shares issued and outstanding at September 30, 2022 and December 31, 2021	—		—
Common stock, $0.001 par value per share; 200,000,000 shares authorized at September 30, 2022 and December 31, 2021; 45,261,618 shares issued and 44,011,151 shares outstanding at September 30, 2022; 31,444,746 shares issued and 30,194,279 shares outstanding at December 31, 2021	44		30
Treasury stock, at cost; 1,250,467 shares at September 30, 2022 and December 31, 2021	—		—
Additional paid-in capital	388,731		287,345
Accumulated other comprehensive loss	(1,669)		(273)
Accumulated deficit	(205,097)		(166,199)
Total stockholders’ equity	182,009		120,903
Total liabilities and stockholders’ equity	$	291,599	$	255,900

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

1

ALPINE IMMUNE SCIENCES, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)

(in thousands, except share and per share amounts)

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
Collaboration revenue	$	8,367	$	8,516	$	27,288	$	18,913
Operating expenses:
Research and development	17,589		18,309		51,487		43,380
General and administrative	4,610		3,470		13,579		10,016
Total operating expenses	22,199		21,779		65,066		53,396
Loss from operations	(13,832)		(13,263)		(37,778)		(34,483)
Other income (expense):
Interest expense	(105)		(203)		(389)		(638)
Interest income	664		52		1,123		166
Other expense	—		—		(72)		—
Loss before taxes	(13,273)		(13,414)		(37,116)		(34,955)
Income tax expense	—		(80)		(1,782)		(211)
Net loss	$	(13,273)	$	(13,494)	$	(38,898)	$	(35,166)
Comprehensive income (loss):
Unrealized loss on investments	(307)		(17)		(1,385)		(1)
Unrealized gain (loss) on foreign currency translation	7		(13)		(11)		(37)
Comprehensive loss	$	(13,573)	$	(13,524)	$	(40,294)	$	(35,204)
Weighted-average shares used to compute basic and diluted net loss per share	31,574,358		24,724,442		31,559,886		24,169,993
Basic and diluted net loss per share	$	(0.42)	$	(0.55)	$	(1.23)	$	(1.45)

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

2

ALPINE IMMUNE SCIENCES, INC.

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (unaudited)

(in thousands, except share amounts)

	Common Stock			Treasury			Additional Paid-in Capital		Accumulated Other Comprehensive Income (Loss)		Accumulated Deficit		Total Stockholders’ Equity
	Shares	Amount		Shares	Amount
Balance, December 31, 2021	30,194,279	$	30	1,250,467	$	—	$	287,345	$	(273)	$	(166,199)	$	120,903
Stock-based compensation	—	—		—	—		2,289		—		—		2,289
Issuance of common stock under equity incentive plans	100,155	—		—	—		550		—		—		550
Unrealized loss on investments	—	—		—	—		—		(774)		—		(774)
Unrealized loss on foreign currency translation	—	—		—	—		—		(14)		—		(14)
Net loss	—	—		—	—		—		—		(7,527)		(7,527)
Balance, March 31, 2022	30,294,434	30		1,250,467	—		290,184		(1,061)		(173,726)		115,427
Stock-based compensation	—	—		—	—		2,335		—		—		2,335
Issuance of common stock under equity incentive plans	41,728	—		—	—		180		—		—		180
Unrealized loss on investments	—	—		—	—		—		(304)		—		(304)
Unrealized loss on foreign currency translation	—	—		—	—		—		(4)		—		(4)
Net loss	—	—		—	—		—		—		(18,098)		(18,098)
Balance, June 30, 2022	30,336,162	30		1,250,467	—		292,699		(1,369)		(191,824)		99,536
Stock-based compensation	—	—		—	—		2,555		—		—		2,555
Issuance of common stock under equity incentive plans	68,989	—		—	—		12		—		—		12
Unrealized loss on investments	—	—		—	—		—		(307)		—		(307)
Unrealized gain on foreign currency translation	—	—		—	—		—		7		—		7
Issuance of common stock in public offering, net of financing costs	13,606,000	14		—	—		93,465		—		—		93,479
Net loss	—	—		—	—		—		—		(13,273)		(13,273)
Balance, September 30, 2022	44,011,151	$	44	1,250,467	$	—	$	388,731	$	(1,669)	$	(205,097)	$	182,009
Balance, December 31, 2020	23,803,183	$	24	50,467	$	—	$	177,947	$	53	$	(115,866)	$	62,158
Stock-based compensation	—	—		—	—		1,597		—		—		1,597
Issuance of common stock under equity incentive plans	78,955	—		—	—		202		—		—		202
Unrealized loss on investments	—	—		—	—		—		(5)		—		(5)
Unrealized loss on foreign currency translation	—	—		—	—		—		(15)		—		(15)
Net loss	—	—		—	—		—		—		(10,643)		(10,643)
Balance, March 31, 2021	23,882,138	24		50,467	—		179,746		33		(126,509)		53,294
Stock-based compensation	—	—		—	—		1,545		—		—		1,545
Issuance of common stock under equity incentive plans	32,741	—		—	—		9		—		—		9
Unrealized gain on investments	—	—		—	—		—		21		—		21
Unrealized loss on foreign currency translation	—	—		—	—		—		(9)		—		(9)
Net loss	—	—		—	—		—		—		(11,029)		(11,029)
Balance, June 30, 2021	23,914,879	24		50,467	—		181,300		45		(137,538)		43,831
Issuance of common stock in Private Placement, net of offering costs	6,489,357	6		—	—		90,805		—		—		90,811
Exchange of common stock for prefunded warrants	(1,200,000)	(1)		1,200,000	—		1		—		—		—
Stock-based compensation	—	—		—	—		1,638		—		—		1,638
Issuance of common stock under equity incentive plans	13,456	—		—	—		69		—		—		69
Unrealized loss on investments	—	—		—	—		—		(17)		—		(17)
Unrealized loss on foreign currency translation	—	—		—	—		—		(13)		—		(13)
Net loss	—	—		—	—		—		—		(13,494)		(13,494)
Balance, September 30, 2021	29,217,692	$	29	1,250,467	$	—	$	273,813	$	15	$	(151,032)	$	122,825

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

3

ALPINE IMMUNE SCIENCES, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

	Nine Months Ended September 30,
	2022		2021
	(unaudited)
Operating activities
Net loss	$	(38,898)	$	(35,166)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	7,179		4,780
Amortization of premium/discount on investments	634		602
Depreciation expense	452		482
Non-cash interest expense	145		213
Loss on sale of property and equipment	68		—
Deferred income tax	113		(61)
Changes in operating assets and liabilities:
Accounts receivable	24,618		—
Prepaid expenses and other current assets	858		(1,500)
Operating lease, right-of-use asset	456		421
Accounts payable and accrued liabilities	3,577		4,133
Deferred revenue	(25,590)		26,086
Operating lease liability	(580)		(509)
Net cash used in operating activities	(26,968)		(519)
Investing activities
Purchases of property and equipment	(296)		(69)
Purchase of investments	(120,335)		(99,957)
Maturities of investments	115,182		51,831
Net cash used in investing activities	(5,449)		(48,195)
Financing activities
Proceeds from sale of common stock and warrants, net of offering costs	94,004		90,812
Repayment of debt	(3,600)		(1,200)
Proceeds from exercise of stock options	742		279
Net cash provided by financing activities	91,146		89,891
Effect of exchange rate on cash and cash equivalents	(11)		(37)
Net increase in cash and cash equivalents and restricted cash	58,718		41,140
Cash and cash equivalents and restricted cash, beginning of period	68,161		35,213
Cash and cash equivalents and restricted cash, end of period	$	126,879	$	76,353
Supplemental Information
Cash paid for interest	$	262	$	432

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

4

ALPINE IMMUNE SCIENCES, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

(Information as of September 30, 2022 and for the three and nine months ended September 30, 2022 and 2021 is unaudited)

1. Description of Business

Alpine Immune Sciences, Inc. (the “Company”, “Alpine”, “we”, “us”, or “our”), together with its consolidated subsidiaries, is a clinical-stage biopharmaceutical company dedicated to discovering and developing innovative, protein-based immunotherapies to treat inflammatory and autoimmune diseases. Our approach includes a proprietary scientific platform that converts native immune system proteins into differentiated, multi-targeted therapeutics. We are seeking to create first- or best-in-class multifunctional immunotherapies via our unique protein engineering technologies to improve outcomes in patients with serious diseases. We were incorporated under the laws of the State of Delaware and are headquartered in Seattle, Washington.

As a result of the COVID-19 pandemic, many companies have experienced disruptions in their operations and in markets served. We have implemented temporary precautionary measures to ensure the well-being of our employees and minimize business disruption. We considered the impact of COVID-19 on the assumptions and estimates used and determined that there were no material adverse impacts to our results of operations and financial position at September 30, 2022. The full extent of the future impacts of the continuing COVID-19 pandemic on our operations is uncertain and may adversely impact our business, including our clinical trials.

2. Summary of Significant Accounting Policies

Basis of Presentation and Use of Estimates

The accompanying condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) and generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Significant estimates inherent in the preparation of the accompanying condensed consolidated financial statements include those used for revenue recognition, accruals for clinical trial activities and other accruals, the potential outcome of uncertain tax positions that have been recognized in our condensed consolidated financial statements or tax returns, and the estimated fair value of equity-based awards. We base our estimates and assumptions on historical experience when available and on various factors we believe to be reasonable under the circumstances. Actual results could differ materially from those estimates.

The accompanying condensed consolidated financial statements as of September 30, 2022 and for the three and nine months ended September 30, 2022 and 2021 and the related interim information contained within the notes to the condensed consolidated financial statements are unaudited. The interim financial statements have been prepared on the same basis as the audited financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The accompanying condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and accompanying notes for the year ended December 31, 2021 included in our Annual Report on Form 10-K for the year ended December 31, 2021, filed with the SEC on March 17, 2022 (“Annual Report”). The results of our operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year.

Principles of Consolidation

Our condensed consolidated financial statements include the financial position and results of operations of Alpine Immune Sciences, Inc. and our wholly owned operating company and subsidiary, AIS Operating Co., Inc., and our wholly-owned subsidiary, Alpine Immune Sciences Australia PTY LTD. All inter-company balances and transactions have been eliminated in consolidation. 

Cash and Cash Equivalents and Restricted Cash

We consider all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of deposits with commercial banks in checking and interest-bearing accounts, and highly liquid money market funds.

5

Restricted cash represents cash drawn on our line of credit used to establish collateral to support the security deposit on our operating lease to rent office and laboratory space in Seattle, Washington.

Periodically, we maintain deposits in financial institutions in excess of government insured limits. We believe we are not exposed to significant credit risk as our deposits, which are held at financial institutions, are high credit quality securities such as money market funds, U.S. Treasury securities, and commercial paper. To date, we have not realized any losses on these deposits.

Investments

Our investments include funds invested in highly liquid money market funds, U.S. Treasury securities, commercial paper, and corporate debt securities with a final maturity of each security of less than two years. These investments are classified as available-for-sale debt securities, which are recorded at fair value based on quoted prices in active markets. We classify our investments maturing within one year of the reporting date as short-term investments.

If the estimated fair value of a debt security is below its amortized cost basis, we evaluate whether it is more likely than not that we will sell the security before its anticipated recovery in market value and whether credit losses exist for the related securities. A credit loss exists if the present value of expected cash flows is less than the amortized cost basis of the security. Credit-related losses are recognized as an allowance for credit losses on the balance sheet with a corresponding adjustment to earnings. Unrealized gains and losses that are unrelated to credit deterioration are reported in other comprehensive income (loss). Purchase premiums and discounts are recognized as interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value deemed to be other than temporary are reflected in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) using the specific-identification method.

3. Net Loss Per Share

Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period.

The net loss per share for the three and nine months ended September 30, 2022 partially reflects 13,606,000 shares of common stock sold in September 2022 through an underwritten public offering. Additionally, we issued 6,489,357 shares of our common stock pursuant to a private placement financing completed in September 2021 and 951,980 shares of our common stock issued in December 2021 pursuant to a private placement financing with Horizon Therapeutics Ireland DAC (“Horizon”). The increased number of shares issued during the periods presented impacts the year-over-year comparability of our net loss per share calculations.

The common stock issuable upon the conversion or exercise of the following dilutive securities has been excluded from the diluted net loss per share calculation because their effect would have been anti-dilutive. Diluted net loss per share, therefore, does not differ from basic net loss per share for the periods presented.

	September 30,
	2022	2021
	(unaudited)
Warrants to purchase common stock	8,838,694	8,851,116
Stock options and restricted stock units outstanding	7,327,631	5,692,264
Total	16,166,325	14,543,380

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4. Cash Equivalents and Investments

The amortized cost and fair value of our cash equivalents and investments are as follows (in thousands):

	September 30, 2022
	(unaudited)
Assets:	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair market value
Money market funds	$	121,916	$	—	$	—	$	121,916
U.S. treasury bills	53,660		—		(804)		52,856
Corporate debt securities and commercial paper	98,215		—		(818)		97,397
Total	$	273,791	$	—	$	(1,622)	$	272,169
Classified as:
Cash equivalents							$	121,916
Short-term investments							122,237
Long-term investments							28,016
Total							$	272,169

	December 31, 2021
Assets:	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair market value
Money market funds	$	50,277	$	—	$	—	$	50,277
U.S. treasury bills	30,006		1		(100)		29,907
Corporate debt securities and commercial paper	117,492		2		(139)		117,355
Total	$	197,775	$	3	$	(239)	$	197,539
Classified as:
Cash equivalents							$	50,277
Short-term investments							94,396
Long-term investments							52,866
Total							$	197,539

All investments held as of September 30, 2022 and December 31, 2021 were classified as available-for-sale debt securities and had contractual maturities of less than two years. There were no realized gains and losses on these securities for the periods presented. The aggregate fair value of available-for-sale debt securities in an unrealized loss position as of September 30, 2022 and December 31, 2021 was $123.2 million and $83.0 million, respectively. Investments in a continuous unrealized loss position for more than twelve months related to our U.S. treasury bills, corporate debt securities and commercial paper, which had a carrying value of $26.0 million and gross unrealized losses of $0.5 million as of September 30, 2022 and none as of December 31, 2021. Our available-for-sale debt securities are invested in highly liquid funds with high credit ratings that have a final maturity of two years or less on the date of purchase. Unrealized losses on these investments were primarily due to changes in interest rates. We evaluated our investments that are in an unrealized loss position and believe it is more likely than not that we will hold these investments until maturity and will recover the amortized cost basis of these investments.

5. Fair Value Measurements

Cash and cash equivalents, restricted cash, receivables, accounts payable and accrued liabilities, which are recorded at invoiced amount or cost, approximate fair value based on the short-term nature of these financial instruments. Fair value is defined as the exchange price received for an asset or paid to transfer a liability, or an exit price, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, is as follows:

Level 1: Quoted prices in active markets for identical assets or liabilities.

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Level 2: Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3: Unobservable inputs supported by little or no market activity and significant to the fair value of the assets or liabilities.

As of September 30, 2022 and December 31, 2021, cash of $4.7 million and $17.6 million, respectively, is excluded from the fair value table below. The following tables summarize our financial assets and liabilities measured at fair value on a recurring basis (in thousands):

	September 30, 2022
	(unaudited)
Assets:	Level 1		Level 2		Level 3		Total
Money market funds	$	121,916	$	—	$	—	$	121,916
U.S. treasury bills	52,856		—		—		52,856
Corporate debt securities and commercial paper	—		97,397		—		97,397
Total	$	174,772	$	97,397	$	—	$	272,169

	December 31, 2021
Assets:	Level 1		Level 2		Level 3		Total
Money market funds	$	50,277	$	—	$	—	$	50,277
U.S. treasury bills	29,907		—		—		29,907
Corporate debt securities and commercial paper	—		117,355		—		117,355
Total	$	80,184	$	117,355	$	—	$	197,539

Our Level 2 assets consist of commercial paper and corporate debt securities. We review trading activity and pricing for our available-for-sale securities as of the measurement date. When sufficient quoted pricing for identical securities is not available, we use market pricing and other observable market inputs for similar securities obtained from various third-party data providers. These inputs either represent quoted prices for similar assets in active markets or have been derived from observable market data.

6. Additional Balance Sheet Information

Prepaid expenses and other current assets consist of the following (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Prepaid research and development	$	2,723	$	3,315
Prepaid insurance	547		454
Prepaid other	430		266
Deferred financing	—		352
Other receivables	295		323
Prepaid expenses and other current assets	$	3,995	$	4,710

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Accrued liabilities consist of the following (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Research and development services	$	8,293	$	5,536
Employee compensation	3,380		3,084
Accrued taxes	1,211		127
Legal and professional fees	822		394
Accrued other	38		276
Accrued liabilities	$	13,744	$	9,417

7. Long-term Debt

In August 2019, we entered into an Amended and Restated Loan and Security Agreement (the “Loan Agreement”) with Silicon Valley Bank (“SVB”), pursuant to which SVB agreed to extend term loans to us with an aggregate principal amount of up to $15.0 million (the “Term Loans”). Borrowings under the Loan Agreement consisted of up to three separate tranches. The initial tranche of $5.0 million was funded in August 2019, $3.0 million of which was used to repay amounts owing under our prior loan and security agreement with SVB. In March 2020, the second tranche of $5.0 million was funded to us. We did not draw down the final tranche of $5.0 million, which expired in July 2020.

The Term Loans accrue interest at a floating per annum rate of 0.25% above the prime rate, subject to a floor of 5.75%, which interest is payable monthly commencing in September 2019. Upon the occurrence and during the continuance of an event of default, a default interest rate will apply that is 4.0% above the otherwise applicable interest rate. The Term Loans were interest only until September 30, 2020, however, under the Loan Agreement our interest only period automatically extended to June 30, 2021 if we received aggregate new capital of at least $40.0 million no later than June 30, 2020. We met this milestone in June 2020 in conjunction with the execution of the agreement with AbbVie Ireland Unlimited Company (“AbbVie”), discussed in detail in Note 9. As a result of the interest only extension, the Term Loans are payable in 25 equal monthly installments of principal plus interest, with the final installment due and payable on July 1, 2023.

We may prepay all, but not less than all, of the Term Loans subject to a prepayment fee equal to $75,000. Additionally, a final payment in the amount of 5.5% of the funded Term Loans is payable to SVB on the date on which the Term Loans are prepaid, paid or become due and payable in full. The final payment fees are recorded in long-term debt in our accompanying Condensed Consolidated Balance Sheets.

The Loan Agreement contains customary representations and warranties, events of default and affirmative and negative covenants. We were in compliance with our covenants as of September 30, 2022. As such, as of September 30, 2022, the classification of the loan is split between current and noncurrent based on the timing of payment obligations. As security for our obligations under the Loan Agreement, we granted SVB a first priority security interest on substantially all of our assets, except intellectual property, and subject to certain other exceptions.

In connection with the Loan Agreement, we issued a warrant to SVB to purchase up to 52,083 shares of our common stock at a price of $4.32 per share, 17,361 shares of which became exercisable in August 2019 after we drew down the initial tranche. In March 2020, after we drew down the second tranche of our Term Loan, an additional 17,361 shares became exercisable. The remaining warrants did not vest and expired upon the expiration of the third tranche of our Term Loan. The fair value of the warrants on the date of issuance for the initial tranche and second tranche was $60,000 and $60,000, respectively, determined using the Black-Scholes option-pricing model, and was recorded as a component of equity and as a debt discount in our accompanying Condensed Consolidated Balance Sheets.

We recorded a total debt discount of $812,000 in connection with the Loan Agreement, which is being amortized to interest expense using the effective interest method over the repayment term of the loan. The unamortized discount included in long-term debt in our accompanying Condensed Consolidated Balance Sheets was $78,000 as of September 30, 2022. Interest expense associated with the amortization of the discount is recorded as non-cash interest expense on our accompanying Condensed Consolidated Statements of Cash Flows.

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Scheduled principal payments on our outstanding debt as of September 30, 2022 under our Loan Agreement, excluding final payment fees, are as follows (in thousands):

	Total
Year ending December 31,	(unaudited)
2022 (remainder of year)	$	1,200
2023	2,800
Total future principal payments	$	4,000

8. Contingencies

Certain credits received related to our research and development expenditures and previously recorded within other income in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) are subject to review by foreign taxing authorities. Upon reaching constructive agreement with the Australian Taxation Office during the quarter ended June 30, 2022, we recorded an estimated current foreign income tax provision of $1.3 million for the expected repayments, which is included within accrued liabilities on our accompanying Condensed Consolidated Balance Sheets.

9. License and Collaboration Agreements

AbbVie

In June 2020, we entered into an option and license agreement with AbbVie (the “AbbVie Agreement”) for the development of ALPN-101, (“acazicolcept”). The AbbVie Agreement grants AbbVie the exclusive option to purchase an exclusive worldwide license to acazicolcept (the “License Option”). The License Option is exercisable by AbbVie at any time and will expire 90 days from the achievement of certain development milestones. If AbbVie exercises the License Option, AbbVie will take over the future development and commercialization. Prior to the exercise of the License Option, we will perform research and development services, including conducting our Phase 2 study in systemic lupus erythematosus, based on an agreed-upon development plan (the “Development Plan”). We will be fully responsible for all costs incurred to conduct the activities under the Development Plan, provided that, AbbVie may be responsible for increased costs under the Development Plan in connection with certain material amendments proposed by AbbVie. We will also be solely responsible, at our sole cost and expense, for manufacturing and regulatory filings for acazicolcept necessary to complete activities under the Development Plan.

In June 2020, in connection with the execution of the AbbVie Agreement, AbbVie paid us a nonrefundable upfront payment of $60.0 million. Prior to the exercise of the License Option, AbbVie has agreed to make cash payments upon our achievement of certain predefined pre-option development milestones (the “Alpine Development Milestones”) up to an aggregate amount of $75.0 million. In 2021, we received $45.0 million of the Alpine Development Milestones. If AbbVie exercises the License Option, they will pay a one-time cash payment of $75.0 million. Following the exercise of the License Option, AbbVie has also agreed to make aggregate cash payments of up to $205.0 million upon AbbVie’s achievement of certain development and commercial milestones and additional aggregate cash payments of up to $450.0 million upon AbbVie’s achievement of certain sales-based cash milestones, collectively referred to as (the “AbbVie Milestones”). Subsequent to commercialization, we are also eligible to receive high single-digit to low double-digit percentage royalties on worldwide net sales of licensed products.

For revenue recognition purposes, we determined that our contractual promises in the AbbVie Agreement are not distinct and are interdependent with our performance obligation to provide research and development services under the Development Plan. Thus, all contractual promises related to the upfront payment and Alpine’s Development Milestones were combined into a single performance obligation. We determined the Alpine Development Milestone payments are probable of significant revenue reversal as the achievement is highly dependent on factors outside our control. Therefore, these milestone payments were fully constrained and were not initially included in the transaction price. In June 2021, we re-evaluated and updated the transaction price to include the achieved portion of the Alpine Development Milestones. We will continue to re-evaluate the transaction price each reporting period and update as uncertain events are resolved or other changes in circumstances occur. We expect to recognize the remaining deferred revenue over the remaining life of the Development Plan, which began in June 2020 and ends upon the later of the exercise or expiration of the option.

The License Option and the AbbVie Milestones were determined not to be performance obligations at the inception of the contract as they did not represent material rights. If exercised, the License Option and AbbVie Milestones will be accounted

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for as a separate contract and will be recognized as revenue if and when triggered. Any consideration related to sales-based royalties and profit-sharing payments will be recognized when the related sales occur.

Horizon

In December 2021, we entered into an exclusive license and collaboration agreement with Horizon (the “Horizon Agreement”) for the development and commercialization of up to four preclinical candidates generated from our unique discovery platform. The agreement includes licensing of one of our existing preclinical biologic therapeutic programs (the “Existing Program”), as well as a research partnership to jointly develop candidates for up to three additional autoimmune and inflammatory disease programs for other designated biological targets (the “Research Programs”). These candidates include previously undisclosed multi-specific fusion protein-based therapeutic candidates for autoimmune and inflammatory diseases. We will advance candidate molecules to predefined preclinical milestones while Horizon will be responsible for the respective costs and, ultimately, Horizon will assume responsibility for development and commercialization activities and costs.

In connection with the execution of the Horizon Agreement in December 2021, we entered into a stock purchase agreement under which Horizon purchased 951,980 shares of our common stock in a private placement for approximately $15.76 per share and aggregate proceeds of $15.0 million. The shares were sold at a 25% premium to the volume-weighted average share price of our common stock for a specified 30-day period prior to entering into the agreement. The fair value of the common stock issued to Horizon of $11.9 million was recorded to equity, based on the closing price of common stock on the effective date of the Horizon Agreement. For accounting purposes, the $3.1 million difference between the cash proceeds and the fair value of the common stock was treated as additional consideration attributable to the Horizon Agreement.

Under the terms of the agreements, Horizon also paid us a non-refundable upfront payment of $25.0 million in the first quarter of 2022. In addition, we are eligible to receive up to $381.0 million per program, or up to approximately $1.5 billion in total, in future success-based payments related to development, regulatory and commercial milestones. Furthermore, we are eligible to receive tiered royalties from a mid-single digit percentage to a low double-digit percentage on global net sales. In addition to proceeds from the non-refundable upfront payment, we have recognized $446,000 in research and development support for ongoing programs through September 30, 2022.

For revenue recognition purposes, we determined the transaction price at inception was $28.1 million, which consists of the upfront payment of $25.0 million and the $3.1 million premium on the stock purchase, and that the Existing Program and each Research Program are distinct performance obligations. We allocated revenue to each performance obligation based on its relative stand-alone selling price. The future success-based payments related to development and regulatory milestones are probable of significant revenue reversal as the achievement is highly dependent on factors outside our control. Therefore, these milestone payments are fully constrained and are not initially included in the transaction price. We will continue to re-evaluate the transaction price each reporting period and update as uncertain events are resolved or other changes in circumstances occur. Any consideration related to commercial milestones and royalties will be recognized when the related sales occur.

Adaptimmune

In May 2019, we entered into a collaboration and licensing agreement with Adaptimmune Therapeutics plc (“Adaptimmune”) to develop next-generation SPEAR T cell products (the “Adaptimmune Agreement”). Under the Adaptimmune Agreement, we are to perform certain research services and grant Adaptimmune an exclusive license to programs from our secreted immunomodulatory protein (“SIP”) and transmembrane immunomodulatory protein (“TIP”) technologies.

Through September 30, 2022, we have recorded a total of $3.0 million in license payments under the terms of the Adaptimmune Agreement consisting of a $2.0 million upfront license payment received in June 2019 and an additional $1.0 million license fee upon Adaptimmune’s selection of an additional research program in June 2022. In addition, we have recorded $1.9 million in research support payments to fund ongoing programs through September 30, 2022. In addition, we are eligible for research support payments, one-time payments and downstream development and commercialization milestones of up to $288.0 million, if respective pre-specified milestones for each program are achieved. We are also eligible to receive low-single digit percentage royalties on worldwide net sales of the applicable products.

For revenue recognition purposes, licensing and research support fees billed under the agreement are being recorded as deferred revenue and recognized to revenue based on employee hours contributed to each performance obligation.

Contract balances and revenue recognition

We report contract assets resulting from unconditional rights to consideration related to upfront payments, and for completed but unpaid research and development services within accounts receivable in our accompanying Condensed Consolidated Balance Sheets. Contract liabilities, representing advance consideration for licensing rights bundled with research

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and development services and other promises for which the underlying performance obligations have not yet been satisfied, are reported as deferred revenue in our accompanying Condensed Consolidated Balance Sheets. Contract liabilities are presented as current and noncurrent based on estimated timing of when the underlying performance obligations will be met. Respective balances are as follows (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Contract Assets	$	382	$	25,000
Contract Liabilities	$	77,013	$	102,603

We use cost-based input methods to measure progress towards completion of our performance obligations and to calculate the corresponding revenue to recognize under our contracts with customers each period. In applying the cost-based input, we use actual costs incurred relative to budgeted costs for each combined performance obligation. Actual costs consist primarily of labor related to internal personnel and third-party contracts. Revenue is recognized based on the level of costs incurred relative to the total estimated costs for the performance obligation. A cost-based input method of revenue recognition requires management to make estimates of costs to complete our performance obligations. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete our performance obligations will be recorded in the period in which changes are identified and amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods.

Collaboration revenue in our accompanying Condensed Consolidated Statements of Operations and Comprehensive Income (Loss), disaggregated by customer, is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
AbbVie	$	6,632	$	8,516	$	17,155	$	18,913
Horizon	1,279		—		9,535		—
Adaptimmune	456		—		598		—
Total collaboration revenue	$	8,367	$	8,516	$	27,288	$	18,913

Revenue recognized during the period that was included in the opening contract liability balance was $26.3 million and $18.9 million for the nine months ended September 30, 2022 and 2021, respectively.

10. Stockholders’ Equity

Securities Offering and Financing Agreement

In September 2022, we sold 13,606,000 shares of our common stock in an underwritten public offering pursuant to our effective shelf registration statement on Form S-3 (File No. 333-256107), resulting in net proceeds of $93.5 million to us, after deducting underwriting discounts, commissions and estimated offering costs. Accrued legal and professional fees of $550,000 incurred in connection with the public offering have been recorded as a reduction to the $94.0 million cash proceeds within additional-paid-in-capital on our accompanying Condensed Consolidated Balance Sheets. An additional 1,903,282 shares of our common stock were sold pursuant to the underwriters’ partial exercise of their over-allotment option, with net proceeds of $13.1 million, after deducting underwriting discounts and commissions, received upon closing on October 4, 2022.

In September 2022, we and Cowen and Company, LLC (“Cowen”) mutually terminated the sales agreement (the “Sales Agreement”) dated July 2, 2021.The Sales Agreement provided that we may sell shares of our common stock from time to time through an “at the market” equity offering for up to $75.0 million in gross cash proceeds, under which Cowen acted as the sales agent. No shares of our common stock were sold under the Sales Agreement. In connection with the termination of the Sales Agreement, we wrote off $488,000 of deferred financing costs to expense, which were previously included within prepaid expenses and other current assets on our accompanying Condensed Consolidated Balance Sheets.

Equity Incentive Plans

On January 1, 2022, in connection with our 2018 Equity Incentive Plan (the “2018 Plan”) annual increase provision, a total of 1,500,000 additional shares were automatically added to the shares authorized under the 2018 Plan.

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During the nine months ended September 30, 2022, we issued stock option grants totaling 1,891,150 shares with a weighted average exercise price of $10.99 per share and 3,750 shares of restricted stock units (“RSUs”) at a grant date fair value of $9.00 per share to eligible employees and board members.

Stock-Based Compensation Expense 

We use the Black-Scholes option pricing model to estimate the fair value of stock options at the grant date. The fair value of RSUs is equal to the closing stock price on the date of grant. We recognize the fair value of stock-based compensation as compensation expense over the requisite service period, which is the vesting period. Stock-based compensation is classified in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) as follows (in thousands): 

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
Research and development	$	1,558	$	936	$	4,212	$	2,596
General and administrative	997		702		2,967		2,184
Total stock-based compensation expense	$	2,555	$	1,638	$	7,179	$	4,780

11. Income Taxes

We are subject to income taxes in the United States and Australia and our effective tax rate is calculated quarterly based upon current assumptions relating to the full year’s estimated operating results and various tax-related items. Each quarter an estimate of the annual effective tax rate is updated should we revise our forecast of earnings based upon our operating results. If there is a change in the estimated effective annual tax rate, a cumulative adjustment is made. Our effective tax rate was 4.82% and 0.61% for the nine months ended September 30, 2022 and 2021, respectively.

The increase in our effective tax rate was primarily due to recognizing current income tax liabilities of $1.3 million during the quarter ended June 30, 2022, which was a result of a cumulative change to our foreign income tax provision for the activities of our wholly owned subsidiary, Alpine Immune Sciences Australia PTY LTD. Following notification of acceptance received during the quarter ended June 30, 2022 of Alpine Immune Sciences Australia PTY LTD’s tax return filed under a revised transfer pricing model for the six-months period ended December 31, 2019, the tax provisions for each open tax year have been recalculated using the same transfer pricing methodology underlying the accepted return. Additionally, consistent with the change to our transfer pricing methodology, we recorded $0.1 million of deferred tax expense resulting from a reduction to our deferred tax assets during the quarter ended June 30, 2022.

The increase in our effective tax rate during the nine months ended September 30, 2022 was also impacted by recognizing current domestic federal income tax liabilities of $0.4 million, which was a result of the mandatory capitalization of research and development expenses under Internal Revenue Code Section 174. As part of the Tax Cuts and Jobs Act of 2017 (TCJA), beginning with the 2022 tax year, expenses that are incurred for research and development in the U.S. will be capitalized and amortized over five years, and expenses that are incurred for research and experimentation outside the U.S. will be capitalized and amortized over 15 years.

The difference between the effective tax rate of 4.82% and the U.S. federal statutory rate of 21% for the nine months ended September 30, 2022, was primarily due to recognizing a full valuation allowance on our domestic deferred tax assets and partial valuation allowance on our foreign deferred tax assets, tax expense resulting from the acceptance of a Voluntary Disclosure Agreement with the Australian Taxation Office, and tax benefits relating to research and development tax credits.

The difference between the effective tax rate of 0.61% and the U.S. federal statutory rate of 21% for the nine months ended September 30, 2021, was primarily due to recognizing a full valuation allowance on our domestic deferred tax assets and partial valuation allowance on our foreign deferred tax assets.

As of September 30, 2022, we determined that, based on an evaluation of our sources of income and all available evidence, both positive and negative, including our latest forecasts and cumulative losses in recent years, it was more likely than not that none of our domestic deferred tax assets would be realized and therefore we continued to record a full domestic valuation allowance. As of September 30, 2022, we determined that it was more likely than not that only a portion of our foreign deferred tax assets would be realized and have recorded a partial foreign valuation allowance.

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

You should read the following Management’s Discussion and Analysis of Financial Condition and Results of Operations in conjunction with our unaudited condensed consolidated financial statements and notes thereto included in Part I, Item 1 of this Quarterly Report on Form 10-Q and with our audited financial statements and related notes thereto and Management’s Discussion and Analysis of Financial Condition and Results of Operations for the year ended December 31, 2021, included in our Annual Report on Form 10-K, or the “Annual Report”, filed with the SEC on March 17, 2022.

Forward-Looking Statements

This Quarterly Report on Form 10-Q contains forward-looking statements and information within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the “safe harbor” created by those sections. In some cases you can identify these statements by forward-looking words such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” “expect,” or similar expressions, or the negative or plural of these words or expressions. You should read these statements carefully because they discuss future expectations, contain projections of future results of operations or financial condition, or state other “forward-looking” information. These statements relate to our future plans, objectives, expectations, intentions and financial performance and the assumptions that underlie these statements. These forward-looking statements include, but are not limited to: 

•our ability to identify, develop and commercialize additional products or product candidates;

•our estimates regarding our expenses, revenues, anticipated capital requirements and our needs for additional financing;

•our ability to obtain funding for our operations;

•the implementation of our business model and strategic plans for our business and technology;

•the timing of the commencement, progress and receipt of data from any of our preclinical and clinical trials;

•the expected results of any preclinical or clinical trial and the impact on the likelihood or timing of any regulatory approval;

•the scope of protection we are able to establish and maintain for intellectual property rights covering our technology and product candidates;

•the anticipated impact of the COVID-19 pandemic on our business, research and clinical development plans and timelines and results of operations;

•the timing or likelihood of regulatory filings and approvals;

•the therapeutic benefits, effectiveness and safety of our product candidates;

•the rate and degree of market acceptance and clinical utility of any future products;

•our ability to maintain and establish collaborations;

•our ability to achieve milestones in our current and any future collaborations;

•our expectations regarding market risk, including interest rate changes and general macroeconomic conditions;

•our expectations regarding the sufficiency of our cash and cash equivalents to fund operations for at least the next 12 months;

•developments relating to our competitors and our industry; and

•our expectations regarding licensing, acquisitions and strategic operations.

These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those anticipated in the forward-looking statements. Factors that might cause such a difference include, but are not limited to, those discussed in this report in Part II, Item 1A — Risk Factors, and elsewhere in this report. Forward-looking statements are based on our management’s beliefs and assumptions and on information currently available to our management. These statements, like all statements in this report, speak only as of their date, and we undertake no obligation to update or revise these statements in light of future developments, except as required by law.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this report, and while we believe such

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information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain and investors are cautioned not to unduly rely upon these statements.

Overview

We are a clinical-stage biopharmaceutical company dedicated to discovering and developing innovative, protein-based immunotherapies to treat inflammatory and autoimmune diseases. Our approach includes a proprietary scientific platform that converts native immune system proteins into differentiated, multi-targeted therapeutics. We are seeking to create first- or best-in-class multifunctional immunotherapies via our unique protein engineering technologies to improve outcomes in patients with serious diseases.

Autoimmune and Inflammatory Diseases

ALPN-303 is a dual B cell cytokine antagonist, being developed for the treatment of B cell mediated inflammatory and autoimmune diseases. Engineered using our proprietary directed evolution platform, ALPN-303 potently inhibits the pleiotropic B cell cytokines B cell activating factor (BAFF, BLyS), and a proliferation inducing ligand, or APRIL, which play key roles in B cell development, differentiation, and survival, and together may contribute to the pathogenesis of multiple autoimmune diseases. Data presented at the American College of Rheumatology, or ACR, Convergence 2021 Annual Meeting and the 2022 European Alliance of Associations for Rheumatology, or EULAR, Annual European Congress, demonstrated that ALPN-303 inhibits the activity of the B cell cytokines APRIL and BAFF more potently than wild-type TACI-Fc counterparts, as well as anti-BAFF and anti-APRIL monoclonal antibodies. In addition, ALPN-303 has been well-tolerated in preclinical models and exhibited superior pharmacokinetics and pharmacodynamics over wild-type TACI-Fc counterparts, including superior serum exposure, suppression of T-dependent antibody production, and/or serum immunoglobulins in mice and/or cynomolgus monkeys.

Preliminary findings from a randomized, placebo-controlled, first-in-human, Phase 1 study of ALPN-303 in adult healthy volunteers (NCT05034484) were presented at our inaugural R&D Day in September 2022 and at subsequent scientific conferences, including the American Society of Nephrology Kidney Week 2022 Meeting and the ACR Convergence Meeting 2022. ALPN-303 was well tolerated as single intravenous (IV) or subcutaneous (SC) doses of up to 960 mg in adult healthy volunteers and exhibited dose-related pharmacokinetic and on-target pharmacodynamic effects. ALPN-303 maintained target coverage of free APRIL for 2-3 and ≥4 weeks with 80 and 240 mg, respectively, corresponding to reductions in serum Ig and antibody-secreting cells. In addition, ALPN-303 also dose-dependently reduced serum Gd-IgA1, an important effector molecule and/or biomarker in IgA nephropathy. Pharmacodynamic analyses further support the potential for convenient subcutaneous therapeutic dosing every four weeks, suggesting potential for more robust activity and greater convenience over related inhibitors of BAFF and/or APRIL. Initiation of basket trials in hematologic and renal indications, and a phase 2 study in systemic lupus erythematosus (SLE), is anticipated in 2023. We anticipate receiving initial clinical data from the first basket trials in late 2023.

ALPN-101, or acazicolcept, is a dual Inducible T cell Costimulator, or ICOS, and CD28 antagonist intended for the treatment of autoimmune and inflammatory diseases. Preclinical studies with acazicolcept have demonstrated efficacy in models of systemic lupus erythematosus, or SLE, Sjögren’s syndrome, or SjS, arthritis, inflammatory bowel disease, multiple sclerosis, type 1 diabetes, uveitis, and graft versus host disease. We have evaluated acazicolcept in a Phase 1 healthy volunteer study and initiated patient dosing in Synergy, a global, randomized, double-blind, placebo-controlled Phase 2 study of acazicolcept in adults with moderate-to-severe SLE. In June 2020, we entered into an Option and License Agreement with AbbVie Ireland Unlimited Company, or AbbVie, which grants AbbVie an exclusive option to take an exclusive license to acazicolcept. Through September 30, 2022, we have received $105.0 million in upfront and pre-option exercise development milestones as part of the AbbVie Agreement.

In December 2021, we entered into an exclusive license and collaboration agreement with Horizon Therapeutics Ireland DAC, or Horizon, which grants Horizon an exclusive license for the development, manufacture and commercialization of one Existing Program and up to three additional Research Programs generated from our libraries of proteins and molecules for research, discovery and identification of additional compounds. Under the terms of the agreement, Horizon made an upfront payment to us of $25.0 million as well as an equity investment for which they paid $15.0 million, a 25% premium to the 30-day volume-weighted average share price as of December 9, 2021. In addition, we are eligible to receive up to $381.0 million per program, or approximately $1.5 billion in total, in future success-based payments related to development, regulatory and commercial milestones as well as tiered royalties on global net sales.

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Immuno-oncology

ALPN-202, or davoceticept, is a conditional CD28 costimulator and dual checkpoint inhibitor intended for the treatment of cancer. On October 24, 2022, we announced the voluntary termination of enrollment of davoceticept clinical studies, including the NEON-1 study of davoceticept as monotherapy and the NEON-2 study of davoceticept in combination with pembrolizumab. The decision to terminate enrollment in the davoceticept studies was made following notification of a second Grade 5 serious adverse event (death) in the NEON-2 study.

Our scientific platform has also generated immune modulatory proteins with the potential of improving engineered cell therapies such as chimeric antigen receptor T cells, T cell receptor-engineered T cells, and tumor infiltrating lymphocytes. In May 2019, we signed a collaboration and license agreement with Adaptimmune Therapeutics plc, or Adaptimmune, to develop next-generation SPEAR™ T cell products which incorporate our secreted and transmembrane immunomodulatory protein (termed SIP™ and TIP™) technology. We intend to continue to leverage our existing pipeline and platform to actively explore and evaluate potential value-creating partnering opportunities.

Our goal is to discover and develop modern therapies to treat patients with serious autoimmune and inflammatory diseases. To achieve our goals, we intend to: 

•aggressively move our lead wholly-owned program ALPN-303 into clinical studies for the treatment of multiple B cell and/or autoantibody-related diseases;

•aggressively move our most advanced autoimmune and inflammatory program acazicolcept through clinical development as part of our collaboration with AbbVie including conducting Synergy, our Phase 2 study for the treatment of SLE; and

•maximize the value of our pipeline and platform via potential partnering activities.

Our operations to date have been limited to business planning, raising capital, developing our platform technology, identifying potential immunotherapy candidates, clinical studies, and other research and development activities. To date, we have financed operations primarily through private placements of common stock and convertible preferred stock, public offerings of common stock, funds received from license and research agreements, debt financing and assets acquired upon the close of our merger with Nivalis Therapeutics Inc., or Nivalis. We do not have any products approved for sale and have not generated any product sales. Since inception and through September 30, 2022, excluding amounts borrowed through debt financing, we have raised an aggregate of approximately $512.9 million to fund operations, of which $279.0 million was from the sale of common stock and warrants, $49.2 million was from the sale of convertible preferred stock, $140.5 million was through our license and collaboration agreements, and $44.1 million in cash, cash equivalents, and marketable securities acquired through the merger with Nivalis. As of September 30, 2022, we had cash, cash equivalents, restricted cash, and investments totaling $277.1 million.

Our net loss was $13.3 million and $13.5 million for the three months ended September 30, 2022 and 2021, respectively, and $38.9 million and $35.2 million for the nine months ended September 30, 2022 and 2021, respectively. We expect to continue incurring significant expenses and operating losses for at least the next several years as we:

•initiate and complete nonclinical studies and clinical trials for our product candidates, including acazicolcept, a dual ICOS/CD28 antagonist program targeting autoimmune and inflammatory disorders, and ALPN-303, a dual B cell cytokine antagonist for B cell-mediated autoimmune and inflammatory diseases;

•contract to manufacture and perform additional process development for our product candidates; 

•continue research and development efforts to build our pipeline beyond the current product candidates; 

•maintain, expand, and protect our intellectual property portfolio; 

•hire additional clinical, quality control, scientific, and management personnel; and 

•add operational and financial personnel to support our product development efforts and operational capabilities applicable to operating as a public company.

We do not expect to generate product revenue unless and until we successfully complete development of, obtain marketing approval for and commercialize our product candidates, either alone or in collaboration with third parties. We expect these activities will take a number of years and our success in these efforts is subject to significant uncertainty. Accordingly, we will need to raise additional capital prior to the regulatory approval and commercialization of any of our product candidates. Until such time, if ever, as we can generate substantial product revenues, we expect to finance our operating activities through equity or debt financings, collaborations or licenses, capital lease transactions, or other available financing transactions. However, additional capital may not be available on reasonable terms, if at all, and if we raise additional funds through the

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issuance of additional equity or debt securities, it could result in dilution to our existing stockholders and increased fixed payment obligations.

Financial Overview

Collaboration Revenue

We derive our collaboration revenue primarily from our collaboration and licensing agreements. We may generate revenue in the future from milestone payments received pursuant to our collaboration and licensing agreements with AbbVie, Horizon, Adaptimmune, or from payments from future license or collaboration agreements, product sales, or government contracts and grants. We expect revenue we generate, if any, will fluctuate from quarter to quarter.

AbbVie

In June 2020, we entered into the AbbVie Agreement for the development of acazicolcept. The AbbVie Agreement grants AbbVie the exclusive option to purchase an exclusive worldwide license to acazicolcept, or the License Option. The License Option is exercisable by AbbVie at any time and will expire 90 days from the achievement of certain development milestones. If AbbVie exercises the License Option, AbbVie will take over the future development and commercialization. Prior to the exercise of the License Option, we will perform research and development services, including conducting our Phase 2 study in SLE, based on an agreed-upon development plan, or the Development Plan. We will be fully responsible for all costs incurred to conduct the activities under the Development Plan, provided that, AbbVie may be responsible for increased costs under the Development Plan in connection with certain material amendments proposed by AbbVie. We will also be solely responsible, at our sole cost and expense, for manufacturing and regulatory filings for acazicolcept necessary to complete activities under the Development Plan.

In June 2020, in connection with the execution of the AbbVie Agreement, AbbVie paid us a nonrefundable upfront payment of $60.0 million. Prior to the exercise of the License Option, AbbVie has agreed to make cash payments upon our achievement of certain predefined pre-option development milestones, or the Alpine Development Milestones, up to an aggregate amount of $75.0 million. In the second quarter of 2021, we achieved $45.0 million of the Alpine Development Milestones. If AbbVie exercises the License Option, they will pay a one-time cash payment of $75.0 million. Following the exercise of the License Option, AbbVie has also agreed to make aggregate cash payments of up to $205.0 million upon AbbVie’s achievement of certain development and commercial milestones and additional aggregate cash payments of up to $450.0 million upon AbbVie’s achievement of certain sales-based cash milestones, collectively referred to as the AbbVie Milestones. Subsequent to commercialization, we are also eligible to receive high single-digit to low double-digit percentage royalties on worldwide net sales of licensed products.

For revenue recognition purposes, we determined that our contractual promises in the AbbVie Agreement are not distinct and are interdependent with our performance obligation to provide research and development services under the Development Plan. Thus, all contractual promises related to the upfront payment and Alpine’s Development Milestones were combined into a single performance obligation. We determined the Alpine Development Milestone payments are probable of significant revenue reversal as the achievement is highly dependent on factors outside our control. Therefore, these milestone payments were fully constrained and were not initially included in the transaction price. In June 2021, we re-evaluated and updated the transaction price to include the achieved portion of the Alpine Development Milestones. We will continue to re-evaluate the transaction price each reporting period and update as uncertain events are resolved or other changes in circumstances occur.

The License Option and the AbbVie Milestones were determined not to be performance obligations at the inception of the contract as they did not represent material rights. If exercised, the License Option and AbbVie Milestones will be accounted for as a separate contract and will be recognized as revenue if and when triggered. Any consideration related to sales-based royalties and profit-sharing payments will be recognized when the related sales occur.

We use a cost-based input method to measure progress toward completion of the performance obligation and to calculate the corresponding revenue to recognize each period. In applying the cost-based input, we use actual costs incurred relative to budgeted costs for the combined performance obligation. These costs consist primarily of internal personnel efforts and third-party contract costs relative to the level of patient enrollment in the study. Revenue will be recognized based on the level of costs incurred relative to the total budgeted costs for the performance obligation. A cost-based input method of revenue recognition requires management to make estimates of costs to complete our performance obligation. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete our performance obligation will be recorded in the period in which changes are identified and

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amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods.

We recognized revenue from the AbbVie Agreement of $6.6 million and $8.5 million for the three months ended September 30, 2022 and 2021, respectively, and $17.2 million and $18.9 million for the nine months ended September 30, 2022 and 2021, respectively. We expect to recognize the remaining deferred revenue over the remainder of our Development Plan, which began in June 2020 and will end upon the later of the exercise or expiration of the option.

Horizon

In December 2021, we entered into an agreement with Horizon, the Horizon Agreement, which grants Horizon an exclusive license for the development, manufacture and commercialization of one Existing Program and up to three additional Research Programs generated from our libraries of proteins and molecules for research, discovery and identification of additional compounds.

Under the terms of the agreement, Horizon made an upfront payment to us of $25.0 million as well as an equity investment for which they paid $15.0 million, a 25% premium to the 30-day volume-weighted average share price as of December 9, 2021. In addition, we are eligible to receive up to $381.0 million per program, or approximately $1.5 billion in total, in future success-based payments related to development, regulatory and commercial milestones as well as tiered royalties on global net sales. We have completed our activities under the Existing Program and will conduct additional activities for up to three Research Programs to deliver compounds meeting agreed criteria. In addition, Horizon will pay us for the costs and expenses of conducting such activities under the deliverables plans. Horizon will then assume responsibility for development and commercialization activities and costs.

For revenue recognition purposes, we determined that the Existing Program and each Research Program are distinct performance obligations. We allocated revenue to each performance obligation based on its relative stand-alone selling price. The future success-based payments related to development and regulatory milestones are probable of significant revenue reversal as the achievement is highly dependent on factors outside our control. Therefore, these milestone payments are fully constrained and are not initially included in the transaction price. We will continue to re-evaluate the transaction price each reporting period and update as uncertain events are resolved or other changes in circumstances occur. Any consideration related to commercial milestones and royalties will be recognized when the related sales occur.

We recognized revenue from the Horizon Agreement of $1.3 million and $9.5 million for the three and nine months ended September 30, 2022, respectively.

Adaptimmune

In May 2019, we entered into a collaboration and licensing agreement with Adaptimmune, or the “AdaptimmuneAgreement, to develop next-generation SPEAR T cell products. Under the Adaptimmune Agreement, we are to perform certain research services and grant Adaptimmune an exclusive license to programs from our secreted immunomodulatory protein, or SIP, and transmembrane immunomodulatory protein, TIP, technologies.

Through September 30, 2022, we have recorded a total of $3.0 million in license payments under the terms of the Adaptimmune Agreement consisting of a $2.0 million upfront license payment received in June 2019 and an additional $1.0 million license fee upon Adaptimmune’s selection of an additional research program in June 2022. Furthermore, we have recorded $1.9 million in research support payments to fund ongoing programs through September 30, 2022. If respective pre-specified milestones for each program are achieved, we are eligible for additional research support payments, one-time payments and downstream development and commercialization milestones of up to $288.0 million, and we are also eligible to receive low-single digit percentage royalties on worldwide net sales of the applicable products.

For revenue recognition purposes, licensing and research support fees billed under the agreement are being recorded as deferred revenue and recognized to revenue based on employee hours contributed to each performance obligation. We recognized revenue from the Adaptimmune Agreement of $0.5 million and $0.6 million for the three and nine months ended September 30, 2022, respectively. No revenue was recognized during the corresponding periods in 2021.

Research and Development Expenses

We focus our resources on research and development activities, including the conduct of preclinical studies, product development, regulatory support, and clinical trials for our product candidates. We recognize research and development expenses as they are incurred. Our research and development expenses consist of:

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•employee-related expenses, including salaries, benefits, taxes, travel, and stock-based compensation expense for personnel in research and development functions;

•expenses related to process development and production of product candidates paid to contract manufacturing organizations;

•costs associated with preclinical activities and regulatory operations, including the cost of acquiring, developing, and manufacturing research material;

•clinical trials and activities related to regulatory filings for our product candidates; and

•allocation of facilities, overhead, depreciation, and amortization of laboratory equipment and other expenses.

The table below summarizes our research and development expenses for the periods indicated. Our direct research and development expenses consist primarily of expenses incurred pursuant to agreements with third-party manufacturing organizations for our product candidates, contract research organizations, or CROs, clinical trial sites, collaborators, and consultants. Other direct costs included direct research and development costs incurred before a selected product candidate begins clinical trials.

We use our employee and infrastructure resources across multiple research and development programs that we are advancing in parallel, and therefore do not allocate salaries, stock-based compensation, employee benefit expenses or other indirect costs related to our research and development to specific product candidates. These expenses are included in indirect research and development expense by type in the table below.

Our research and development expenses are summarized as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
Direct research and development expense by program:
Acazicolcept	$	2,711	$	3,961	$	8,117	$	8,115
Davoceticept	2,354		4,752		8,435		7,934
ALPN-303	2,665		3,561		8,931		9,779
Other	299		170		642		438
Total direct research and development expense	8,029		12,444		26,125		26,266
Indirect research and development expense by type:
Personnel-related costs	8,011		4,639		20,719		12,423
Research and development supplies and services	655		659		2,105		2,230
Allocated facility, equipment and other expenses	894		567		2,538		2,461
Total indirect research and development expense	9,560		5,865		25,362		17,114
Total research and development expense	$	17,589	$	18,309	$	51,487	$	43,380

We expect our direct and indirect research and development expenses to increase for the foreseeable future as we continue to develop our platform and product candidates. We remain focused on using our resources to further advance ALPN-303’s broad development plan. We expect the future increase in investment in this program, including a phase 2 study in SLE, and open label basket studies in glomerulonephritis and autoimmune cytopenias, to more than offset the expected significant decrease in costs to support davoceticept as a result of the voluntary termination of enrollment of davoceticept clinical studies as announced by us on October 24, 2022.

The successful development of our platform and product candidates is highly uncertain. At this time, we cannot reasonably estimate the nature, timing, or costs of the efforts necessary to finish developing any of our product candidates or the period in which material net cash, if any, from these product candidates may commence. This is due to the numerous risks and uncertainties associated with developing therapeutics, including the uncertainty of:

•the scope, rate of progress, expense, and results of clinical trials;

•the scope, rate of progress, and expense of process development and manufacturing;

•preclinical and other research activities; and

•the timing of regulatory approvals.

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General and Administrative Expenses

General and administrative expenses consist primarily of salaries and related costs for employees in executive, business development, finance, legal, and administrative functions. Other significant general and administrative expenses include professional fees for accounting and legal services, expenses associated with obtaining and maintaining patents and other intellectual property, and allocation of facility and overhead costs.

We expect general and administrative expenses to increase as we expand infrastructure, headcount, and continue to prosecute our patents and other intellectual property. Other increases could potentially include increased costs for insurance, costs related to the hiring of additional personnel, and increased fees for directors, outside consultants, lawyers, and accountants. We expect to incur significant costs to comply with corporate governance, internal controls, and similar requirements applicable to public companies.

Interest Expense

Interest expense consists primarily of interest associated with our term loan with Silicon Valley Bank, or SVB, and the amortization of the related debt discount. 

Interest Income

Interest income consists of interest earned on our cash, cash equivalents, and investments.

Other Expense

Other expense consists of a loss on the sale of equipment.

Income Tax Expense

Income tax expense for the 2022 period primarily relates to a cumulative change to our foreign income tax provision while income tax expense for the 2021 period relates to the removal of the valuation allowance against our foreign deferred tax assets as we had generated sufficient foreign taxable income to utilize all historical operating losses.

JOBS Act

We ceased to be an “emerging growth company” under the JOBS Act effective December 31, 2020. However, for so long as we are not classified as an “accelerated filer” or “large accelerated filer” pursuant to SEC rules, we will continue to be exempt from the auditor attestation requirements of Section 404(b) of Sarbanes-Oxley.

Critical Accounting Policies and Estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our condensed consolidated financial statements, which we have prepared in accordance with generally accepted accounting principles in the United States, or GAAP. The preparation of these condensed consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, as well as the reported revenues and expenses during the reporting periods. We evaluate these estimates and judgments on an ongoing basis. We base our estimates on historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Our actual results may differ from these estimates under different assumptions or conditions.

Our significant accounting policies are more fully described in Note 2 of the accompanying condensed consolidated financial statements and in Note 2 to the audited financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2021. There have been no significant or material changes in our significant accounting policies during the nine months ended September 30, 2022, as compared to those disclosed in our Annual Report.

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Results of Operations

Comparison of Three Months Ended September 30, 2022 and 2021

The following table summarizes our results of operations for the three months ended September 30, 2022 and 2021 (in thousands):

	Three Months Ended September 30,				$ Change
	2022		2021
	(unaudited)
Collaboration revenue	$	8,367	$	8,516	$	(149)
Operating expenses:
Research and development	17,589		18,309		(720)
General and administrative	4,610		3,470		1,140
Total operating expenses	22,199		21,779		420
Loss from operations	(13,832)		(13,263)		(569)
Other income (expense):
Interest expense	(105)		(203)		98
Interest income	664		52		612
Loss before taxes	(13,273)		(13,414)		141
Income tax expense	—		(80)		80
Net loss	$	(13,273)	$	(13,494)	$	221

Collaboration Revenue

Revenue for the three months ended September 30, 2022 consists of $6.6 million related to the AbbVie Agreement, $1.3 million related to the Horizon Agreement, and $0.5 million related to the Adaptimmune Agreement. Revenue for the three months ended September 30, 2021 consists of $8.5 million related to the AbbVie Agreement.

Research and Development Expenses

The $0.7 million decrease in research and development expenses was primarily attributable to decreases of $3.1 million in clinical trial activities and $1.4 million in direct research activities. These decreases were partially offset by an increase of $3.4 million in research and development personnel-related expenses due to increased headcount, which includes $0.6 million in higher non-cash stock-based compensation expense, and $0.3 million in allocated overhead and facilities expenses.

General and Administrative Expenses

The $1.1 million increase in general and administrative expenses was primarily attributable to increases of $0.8 million in personnel-related expenses, which includes $0.3 million in higher non-cash stock-based compensation expense, and $0.7 million in legal and professional services, which includes $0.5 million related to the write-off of previously deferred financing costs. The increases were partially offset by $0.4 million related to lower allocated overhead and facilities expenses.

Other Income (Expense)

The $0.7 million increase in other income (expense) is attributable to higher interest income due to higher investment balances and rising interest rates, and lower interest expense due to amortization of the underlying term loan balance.

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Comparison of Nine Months Ended September 30, 2022 and 2021

The following table summarizes our results of operations for the nine months ended September 30, 2022 and 2021 (in thousands):

	Nine Months Ended September 30,				$ Change
	2022		2021
	(unaudited)
Collaboration revenue	$	27,288	$	18,913	$	8,375
Operating expenses:
Research and development	51,487		43,380		8,107
General and administrative	13,579		10,016		3,563
Total operating expenses	65,066		53,396		11,670
Loss from operations	(37,778)		(34,483)		(3,295)
Other income (expense):
Interest expense	(389)		(638)		249
Interest income	1,123		166		957
Other expense	(72)		—		(72)
Loss before taxes	(37,116)		(34,955)		(2,161)
Income tax expense	(1,782)		(211)		(1,571)
Net loss	$	(38,898)	$	(35,166)	$	(3,732)

Collaboration Revenue

Revenue for the nine months ended September 30, 2022 consists of $17.2 million related to the AbbVie Agreement, $9.5 million related to the Horizon Agreement, and $0.6 million related to the Adaptimmune Agreement. Revenue for the nine months ended September 30, 2021 consists of $18.9 million related to the AbbVie Agreement.

Research and Development Expenses

The $8.1 million increase in research and development expenses was primarily attributable to increases of $8.3 million in personnel-related expenses due to increased headcount, which includes $1.6 million in higher non-cash stock-based compensation expense, and $3.5 million in clinical trial activity. These increases were partially offset by decreases of $2.4 million in direct research activities and $1.3 million in contract manufacturing and process development of our product candidates.

General and Administrative Expenses

The $3.6 million increase in general and administrative expenses was primarily attributable to increases of $2.2 million in personnel-related expenses, which includes $0.8 million in higher non-cash stock-based compensation expense, $1.1 million in legal and professional services, which includes $0.5 million related to the write-off of previously deferred financing costs, and $0.2 million in higher allocated overhead and facilities to support the growth and expansion of our business.

Other Income (Expense)

The $1.1 million increase in other income (expense) is primarily attributable to higher interest income due to higher investment balances and rising interest rates, and lower interest expense due to amortization of the underlying term loan balance.

Income Tax Expense

The $1.6 million increase in income tax expense primarily relates to a $1.3 million cumulative change to our foreign income tax provision as a result of tax return filed under a revised transfer pricing model for the activities of our wholly owned subsidiary, Alpine Immune Sciences Australia PTY LTD.

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Liquidity and Capital Resources

Sources of Liquidity

To date, we have financed our operations primarily through the sale of equity securities, debt, payments received under our collaboration agreements, and funds acquired upon the close of our merger with Nivalis. As of September 30, 2022, we had cash, cash equivalents, restricted cash, and investments totaling $277.1 million. Except for any obligations of our collaborators to make milestone payments under our agreements with them, we do not have any committed external sources of capital. Until such time as we can generate substantial product revenue, if ever, we expect to finance our cash needs through a combination of collaboration agreements and equity or debt financings.

Equity Financing Agreements

In September 2022, we entered into an underwriting agreement, the Underwriting Agreement, with Morgan Stanley & Co. LLC, SVB Securities LLC and Cowen and Company, LLC, acting as representatives of the several underwriters named therein, or, collectively, the Underwriters, pursuant to which we sold 13,606,000 shares of our common stock, or the Firm Shares, in an underwritten public offering pursuant to our effective shelf registration statement on Form S-3 (File No. 333-256107). We also granted the Underwriters a 30-day option to purchase up to an additional 2,040,900 shares of common stock, or the Option Shares. The offering price of the Firm Shares and the Option Shares to the public was $7.35 per share. The Underwriters purchased the Firm Shares from us pursuant to the Underwriting Agreement at a price of $6.909 per share. The net proceeds of the public offering were approximately $93.5 million, after deducting underwriting discounts, commissions and estimated offering expenses. In October 2022, 1,903,282 Option Shares were sold pursuant to the underwriters’ partial exercise of their over-allotment option at a price per share of $6.909, with net proceeds of $13.1 million.

In December 2021, in connection with the execution of the Horizon Agreement, we entered into a Stock Purchase Agreement with Horizon, or the Purchase Agreement, in which Horizon made an equity investment in Alpine of 951,980 shares of our common stock for approximately $15.76 per share, for an aggregate purchase price of $15.0 million. The purchase price represents a 25% premium to the volume-weighted average share price of our common stock for the 30-day period ended December 9, 2021. The shares were subject to lock-up restrictions, which, subject to certain exceptions, prohibit Horizon from selling the shares for a period of six months after the date of the Purchase Agreement. The shares were recorded at the fair value of our common stock on the effective date of the Horizon Agreement, with the excess of the proceeds recorded to deferred revenue.

In September 2021, we entered into a securities purchase agreement, or the 2021 Securities Purchase Agreement, for a private placement with a select group of institutional investors, pursuant to which we sold 6,489,357 shares of our common stock, or the Shares, and prefunded warrants to purchase 3,191,487 Shares, or the Prefunded Warrants. The purchase price for each Share and for each Prefunded Warrant was $9.40 per share, for an aggregate purchase price of approximately $91.0 million. The Prefunded Warrants became fully exercisable upon the closing date and have an exercise price of $0.001 per share. In connection with the 2021 Securities Purchase Agreement, approximately 3.7 million of the Shares issued and approximately 2.3 million of the Prefunded Warrants issued, for gross proceeds of approximately $57.0 million, were issued to certain stockholders whose beneficial ownership exceeded 5% prior to completion of the 2021 Securities Purchases Agreement.

In July 2021, we entered into a sales agreement, or the Sales Agreement, with Cowen and Company, LLC, or Cowen, pursuant to which we may sell shares of our common stock from time to time through an “at the market” equity offering for up to $75.0 million in gross cash proceeds. Cowen will act as the sales agent and will be entitled to compensation for services of up to 3.0% of the gross sales price per share of all shares sold through Cowen under the Sales Agreement. The shares would be issued pursuant to our effective shelf registration statement on Form S-3 (File No. 333-256107). We filed a prospectus supplement, dated July 2, 2021, with the SEC in connection with the offer and sale of the shares pursuant to the Sales Agreement. In connection with our September 2022 public offering, we and Cowen mutually terminated the Sales Agreement, and, as a result, we wrote off $0.5 million in deferred financing costs to expense, which were previously included within prepaid expenses and other current assets on our accompanying Condensed Consolidated Balance Sheets. No shares of common stock were sold under the Sales Agreement prior to its termination.

In July 2020, we entered into a securities purchase agreement, or the 2020 Securities Purchase Agreement, for a private placement with a select group of institutional investors, pursuant to which we sold 5,139,610 units, or the Common Units, and 790,710 units, or the Prefunded Warrant Units, for an aggregate purchase price of $60.0 million. Each Common Unit consists of one share of our common stock plus a warrant to purchase 0.3 shares of common stock, or the Common Stock Warrants, and each Prefunded Warrant Unit consists of one prefunded warrant to purchase one share of common stock, or the Prefunded Warrants, plus one Common Stock Warrant to purchase 0.3 shares of common stock. The Prefunded Warrant Units and the Common Units are collectively referred to as the Units and each Unit has a purchase price of $10.1175. The Common

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Stock Warrants have an exercise price of $12.74 and a term of 3.5 years. The Prefunded Warrants became fully exercisable upon the closing date and have an exercise price of $0.001 per share.

In January 2019, we entered into a securities purchase agreement, or the 2019 Securities Purchase Agreement, with a limited number of accredited investors, pursuant to which we sold approximately 4.7 million units, or the 2019 Units, for an aggregate purchase price of $25.3 million in a private placement, which we refer to as the Private Placement. Each 2019 Unit has a purchase price of $5.37 and consists of one share of our common stock and a warrant to purchase 0.39 shares of common stock. Pursuant to the terms of the 2019 Securities Purchase Agreement, we issued approximately 4.7 million shares of common stock and warrants to purchase an aggregate of approximately 1.8 million shares of common stock. The warrants have an exercise price of $12.74 and have a term of five years.

Debt Financing Agreements

As of September 30, 2022, we had $4.6 million in remaining principal balance and final payment fees outstanding under our 2019 term loan agreement with Silicon Valley Bank and were in compliance with our respective loan covenants. See Note 7 for further discussion of our Term Loans.

Cash Flows

The following is a summary of our cash flows (in thousands):

	Nine Months Ended September 30,
	2022		2021
	(unaudited)
Net cash used in operating activities	$	(26,968)	$	(519)
Net cash used in investing activities	(5,449)		(48,195)
Net cash provided by financing activities	91,146		89,891

Net Cash Used in Operating Activities:

Net cash used in operating activities was $27.0 million during the nine months ended September 30, 2022, and consisted of our net loss of $38.9 million, partially offset by changes of $3.3 million in our net operating assets and liabilities, and $8.6 million in net non-cash adjustments, which primarily relate to stock-based compensation, depreciation and amortization. The $3.3 million increase in our net operating assets and liabilities was largely driven by the receipt of a $25.0 million upfront payment from Horizon, partially offset by other changes in net operating assets and liabilities.

Net cash used in operating activities was $0.5 million during the nine months ended September 30, 2021, and consisted of our net loss of $35.2 million, partially offset by an increase of $28.6 million in our net operating assets and liabilities and an increase of $6.0 million in our net non-cash adjustments, which primarily relate to stock-based compensation, depreciation and amortization.

Net Cash Used in Investing Activities:

Cash flows from investing activities primarily reflect cash used to purchase investments and proceeds from the maturities and sales of investments, thus causing a shift between our cash and cash equivalents and investment balances. We manage our cash usage with respect to our total cash, cash equivalents and investments.

Net cash used in investing activities was $5.4 million during the nine months ended September 30, 2022, and consisted primarily of net purchases of investments in U.S. Treasury securities, commercial paper, and corporate debt securities using excess liquidity consisting primarily of funds received in connection with entering into the Horizon Agreement, as well as the purchases of property and equipment, primarily lab equipment to support our research and development efforts.

Net cash used in investing activities was $48.2 million during the nine months ended September 30, 2021, and consisted primarily of our purchases and maturities of investments in U.S. Treasury securities, commercial paper, and corporate debt securities, as well as the purchases of property and equipment, primarily lab equipment, to support our research and development efforts.

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Net Cash Provided by Financing Activities:

Net cash provided by financing activities was $91.1 million during the nine months ended September 30, 2022, and consisted primarily of cash proceeds of $94.0 million, net of underwriting fees and commissions, related to the sale of 13,606,000 shares of our common stock in an underwritten public offering pursuant to our effective shelf registration statement on Form S-3 (File No. 333-256107), and $0.7 million related to the exercise of stock options. These increases were partially offset by $3.6 million in principal payments on our debt.

Net cash provided by financing activities was $89.9 million during the nine months ended September 30, 2021, and consisted primarily of the net proceeds of $90.8 million related to the sale of approximately 6.5 million shares of common stock and 3.2 million prefunded warrants to purchase common stock under our 2021 Securities Purchase Agreement, and $0.3 million related to the exercise of stock options. These increases were partially offset by $1.2 million in principal payments on our debt.

Funding Requirements

We have incurred operating losses since inception. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we continue our research and preclinical and clinical development of our product candidates; expand the scope of our current studies for our product candidates; initiate additional preclinical, clinical or other studies for our product candidates, including under any collaboration agreements; change or add additional manufacturers or suppliers; seek regulatory and marketing approvals for any of our product candidates that successfully complete clinical studies; seek to identify, evaluate and validate additional product candidates; acquire or in-license other product candidates and technologies; maintain, protect and expand our intellectual property portfolio; attract and retain skilled personnel; and experience any delays or encounter issues with any of the above. Additionally, we have ongoing obligations with respect to our Loan Agreement, as described above, and our Operating Lease and certain Contingencies, as described below.

Until such time as we can generate substantial product revenue, if ever, we expect to finance our cash needs through a combination of equity or debt financings and collaboration agreements. To the extent that we raise additional capital through the future sale of equity or debt, the ownership interest of our stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our existing common stockholders. If we raise additional funds through collaboration agreements in the future, we may have to relinquish valuable rights to our technologies, future revenue streams 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 product development or future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Our future capital requirements are difficult to forecast and will depend on many factors, including:

•the number and characteristics of the future product candidates we pursue either from our internal research efforts or through acquiring or in-licensing other product candidates or technologies;

•the scope, progress, results and costs of independently researching and developing any of our future product candidates, including conducting preclinical research and clinical trials;

•whether our existing collaborations generate substantial milestone payments and, ultimately, royalties on future approved products for us;

•the timing of, and the costs involved in, obtaining regulatory approvals for any future product candidates we develop independently;

•the cost of future commercialization activities, if any;

•the cost of manufacturing our future product candidates and products, if any;

•our ability to maintain our existing collaborations and to establish new collaborations, licensing or other arrangements and the financial terms of such arrangements;

•the costs of preparing, filing, prosecuting, maintaining, defending and enforcing patents, including litigation costs and the outcome of such litigation; and

•the timing, receipt and amount of sales of, or royalties on, our current or future collaborators’ product candidates, and our future products, if any.

We have considered that our long-term operations anticipate continuing net losses and the need for potential equity or debt financing. We have also considered that new collaborations or selectively partnering our technology or programs may provide other sources of capital. However, there can be no assurances that additional funding or other sources of capital will be available on terms acceptable to us, or at all. Based on our current operating plan, we believe our available cash and cash

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equivalents and investments, will be sufficient to fund our planned level of operations for at least the next 12 months. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we expect. Additionally, the process of testing drug candidates in preclinical and clinical studies is costly, and the timing of progress in these studies remains uncertain. Further, inflation may affect our use of capital resources by increasing our cost of labor and clinical trial expenses. Our long-term funding requirements will consist of operational, capital, and manufacturing expenditures, including those contractual commitments described above. Because of the inherent risks and uncertainties associated with the development and commercialization of our product candidates, we are unable to estimate the amounts of capital outflows and operating expenditures associated with our long-term anticipated preclinical studies and clinical trials.

Operating Lease

In March 2019, we entered into a lease with ARE-Seattle No. 28, LLC, or the Landlord, for 27,164 square feet of office and laboratory space located at 188 East Blaine Street, Seattle, Washington. The term of the lease is 10.8 years with one option to extend the term by 5 years. The lease term commenced in June 2019. The “Rent Commencement Date” began in March 2020, nine months after the commencement date. We were not required to pay base rent from the Rent Commencement Date through November 2020, the last day of the ninth month following the Rent Commencement Date. The annual base rent under the lease is $1.7 million for the first year and will increase by 3.0% each year thereafter. We received a tenant improvement allowance of $5.4 million, which is included in our base rent, and a maximum additional tenant improvement allowance of $1.8 million, which will result in additional rent amortized over the term of the lease at an annual rate of 8.0%. The lease also requires us to pay additional amounts for operating and maintenance expenses. In March 2019, in connection with the lease, we provided a $254,000 letter of credit as a security deposit, which is recorded as restricted cash in our accompanying Condensed Consolidated Balance Sheets.

Contingencies

Certain credits received related to our research and development expenditures and previously recorded within other income in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) are subject to review by foreign taxing authorities. Upon reaching constructive agreement with the Australian Taxation Office during the quarter ended June 30, 2022, we recorded an estimated current foreign income tax provision of $1.3 million for the expected repayments, which is included within accrued liabilities on our accompanying Condensed Consolidated Balance Sheets.

Item 3. Quantitative and Qualitative Disclosures About Market Risk.

As a “smaller reporting company,” as defined by Rule 12b-2 of the Exchange Act, and pursuant to Item 305 of Regulation S-K, we are not required to provide quantitative and qualitative disclosures about market risk.

Item 4. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our Chief Executive Officer and Chief Financial Officer, evaluated the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act), as of the end of the period covered by this report. Based upon the evaluation, our Chief Executive Officer and Chief Financial Officer concluded that, as of the end of the period covered by this report, our disclosure controls and procedures were effective, in design and operation, at the reasonable assurance level.

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Changes in Internal Control over Financial Reporting

Our management, including our Chief Executive Officer and Chief Financial Officer, evaluated any changes in our internal control over financial reporting during the period ended September 30, 2022, and has concluded that there were no changes that materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Inherent Limitation on the Effectiveness of Internal Control

The effectiveness of any system of internal control over financial reporting, including ours, is subject to inherent limitations, including the exercise of judgment in designing, implementing, operating, and evaluating the controls and procedures, and the inability to eliminate misconduct completely. Accordingly, any system of internal control over financial reporting, including ours, no matter how well designed and operated, can only provide reasonable, not absolute assurances. In addition, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate. We intend to continue to monitor and upgrade our internal controls as necessary or appropriate for our business, but cannot assure you that such improvements will be sufficient to provide us with effective internal control over financial reporting.

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PART II: OTHER INFORMATION

Item 1. Legal Proceedings.

From time to time, we may become involved in legal proceedings or be subject to claims arising in the ordinary course of our business. We are not presently a party to any legal proceedings that, in the opinion of our management, would reasonably be expected to have a material adverse effect on our business, financial condition, operating results or cash flows if determined adversely to us. Regardless of the outcome, litigation can have an adverse impact on us because of defense and settlement costs, diversion of management resources and other factors.

Item 1A. Risk Factors.

You should carefully consider the following risk factors, in addition to the other information contained in this Quarterly Report on Form 10-Q, including Management’s Discussion and Analysis of Financial Condition and Results of Operations included in Part I, Item 2, and our condensed consolidated financial statements and related notes. If any of the events described in the following risk factors and the risks described elsewhere in this report occurs, our business, operating results and financial condition could be seriously harmed. Our Risk Factors are not guarantees that no such conditions exist as of the date of this report and should not be interpreted as an affirmative statement that such risks or conditions have not materialized, in whole or in part. This report on Form 10-Q also contains forward-looking statements that involve risks and uncertainties. Our actual results could differ materially from those anticipated in the forward-looking statements as a result of factors that are described below and elsewhere in this report.

Risks Related to Our Pipeline and Product Development

Our approach to the discovery and development of innovative therapeutic treatments based on our technology is unproven and may not result in marketable products.

We plan to develop novel protein-based immunotherapies in part via our proprietary directed evolution platform for the treatment of autoimmune and inflammatory diseases. The potential to create therapies capable of working within and/or modulating an immune synapse, forcing a synapse to occur, or preventing a synapse from occurring is an important, novel attribute of the majority of our approaches. However, the scientific research forming the basis of our efforts to develop therapeutic candidates based on our platform is relatively new. Further, the scientific evidence to support the feasibility of developing therapeutic treatments based on our platform is both preliminary and limited.

Relatively few therapeutic candidates based on immunoglobulin superfamily, or IgSF, domains, or tumor necrosis factor receptor super family, or TNFRSF, domains, have been tested in humans. We may discover the therapeutic candidates developed using our scientific platform do not possess certain properties required for the therapeutic candidate to be effective. We currently have only limited data to suggest we can introduce these necessary therapeutic properties into variant Ig domain, or vIgD or variant TNF(R) domain, or vTD, based therapeutic candidates. In addition, vIgDs or vTDs may demonstrate different chemical and pharmacological properties in human subjects or patients than they do in laboratory studies. Even if our programs have successful results in animal studies, they may not demonstrate the same chemical and pharmacological properties in humans and may interact with human biological systems in unforeseen, ineffective, or harmful ways. While we continue to evaluate our vIgDs and vTDs preclinically and clinically, the risk profile in humans is still being fully assessed. Undesirable side effects that may be caused by our therapeutic candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign authorities. Such side effects could also affect patient recruitment or the ability of enrolled patients to complete clinical trials or result in potential product liability claims. For example, we recently voluntarily terminated enrollment in both clinical studies involving davoceticept, including the NEON-1 study of davoceticept as monotherapy and the NEON-2 study of davoceticept in combination with pembrolizumab. The decision to terminate enrollment in the davoceticept studies was made following notification of a second Grade 5 serious adverse event (death) in the NEON-2 study. Occurrences like these may harm our business, financial condition and prospects significantly. As a result, we may never succeed in developing a marketable therapeutic, we may not become profitable, and the value of our common stock may decline.

Further, we believe that the FDA has little prior experience with vIgDs or vTDs, which may increase the complexity, uncertainty, and length of the regulatory approval process for our therapeutic candidates. Our company and our current collaborators, or any future collaborators, may never receive approval to market and commercialize any therapeutic candidate. Even if our company or a collaborator obtains regulatory approval, the approval may be for disease indications or patient populations not as broad as we intended or desired or may require labeling, including significant use or distribution restrictions or safety warnings. Our company or a collaborator may be required to perform additional or unanticipated clinical trials to

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obtain approval or be subject to post-marketing testing requirements to maintain regulatory approval. If therapeutic candidates we develop using our scientific platform prove to be ineffective, unsafe, or commercially unviable, our entire platform and pipeline would have little, if any, value, which could have a material adverse effect on our business, financial condition, results of operations, and prospects.

The market may not be receptive to our therapeutic products based on a novel therapeutic modality, and we may not generate any future revenue from the sale or licensing of therapeutic products.

Even if approval is obtained for a therapeutic candidate, we may not generate or sustain revenue from sales of the therapeutic product due to factors such as whether the therapeutic product can be sold at a competitive price and otherwise accepted in the market. Therefore, any revenue from sales of the therapeutic product may not offset the costs of development. The therapeutic candidates we are developing are based on new technologies and therapeutic approaches. Market participants with significant influence over acceptance of new treatments, such as physicians and third-party payors, may not adopt a treatment based on our therapeutic products, and we may not be able to convince the medical community and third-party payors to accept and use, or to provide favorable coverage or reimbursement for, any therapeutic products developed by our company, our existing collaborator, or any future collaborators. Market acceptance of our therapeutic products will depend on, among other factors:

•the timing of our receipt of any marketing and commercialization approvals;

•the terms and scope of any approvals and the countries in which approvals are obtained;

•the safety and efficacy of our therapeutic products;

•the prevalence and severity of any adverse side effects associated with our therapeutic products;

•the prevalence and severity of any adverse side effects associated with therapeutics of the same type or class as our therapeutic products;

•limitations or warnings contained in any labeling approved by the FDA or other regulatory authority;

•relative convenience and ease of administration of our therapeutic products;

•the willingness of patients to accept, and the willingness of physicians to prescribe, any new methods of administration;

•the success of our physician education programs;

•the availability of adequate government and third-party payor coverage and reimbursement;

•the willingness of patients to pay out-of-pocket in the absence of coverage by government and third-party payors;

•the pricing of our products, particularly as compared to alternative treatments;

•our ability to compliantly and effectively market and sell our products;

•the timing of market introduction of our therapeutic products as well as alternative treatments; and

•availability of alternative effective treatments for the disease indications our therapeutic products are intended to treat and the relative risks, benefits, and costs of those treatments.

With our development focus, these risks may increase to the extent this field becomes more competitive or less favored in the commercial marketplace. Additional risks apply in relation to any disease indications we pursue which are classified as rare diseases and allow for orphan drug designation by regulatory agencies in major commercial markets, such as the United States, European Union, and Japan. Because of the small patient population for a rare disease, if pricing is not approved or accepted in the market at an appropriate level for an approved therapeutic product with orphan drug designation, such drug may not generate enough revenue to offset costs of development, manufacturing, marketing, and commercialization despite any benefits received from the orphan drug designation, such as market exclusivity, assistance in clinical trial design, or a reduction in user fees or tax credits related to development expense. Market size is also a variable in disease indications classified as rare. Our estimates regarding potential market size for any rare indication may be materially different from what we discover to exist at the time we commence commercialization, if any, for a therapeutic product, which could result in significant changes in our business plan and have a material adverse effect on our business, financial condition, results of operations, and prospects.

If a therapeutic product with orphan drug designation subsequently receives the first FDA approval for the indication for which it has such designation, the therapeutic product is entitled to orphan product exclusivity, which means the FDA may not approve any other applications to market the same therapeutic product for the same indication, except in very limited circumstances, for seven years. Orphan drug exclusivity, however, could also block the approval of one of our therapeutic

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products for seven years if a competitor obtains approval of the same therapeutic product as defined by the FDA or if our therapeutic product is determined to be within the same class as the competitor’s therapeutic product for the same indication or disease.

As in the United States, we may apply for designation of a therapeutic product as an orphan drug for the treatment of a specific indication in the European Union before the application for marketing authorization is made. Sponsors of orphan drugs in the European Union can enjoy economic and marketing benefits, including up to ten years of market exclusivity for the approved indication unless another applicant can show its therapeutic product is safer, more effective, or otherwise clinically superior to the orphan-designated therapeutic product. The respective orphan designation and exclusivity frameworks in the United States and in the European Union are subject to change, and any such changes may affect our ability to obtain EU or U.S. orphan designations in the future.

Our therapeutic candidates are in early stages of development and may fail in development or suffer delays that materially and adversely affect their commercial viability.

We have no products on the market and all of our therapeutic candidates are in early stages of development. Our ability to achieve and sustain profitability depends on obtaining regulatory approval and Institutional Review Board, or IRB, approval to conduct clinical trials at particular sites, obtaining regulatory approvals to market our therapeutic candidates and successfully commercializing our therapeutic candidates, either alone or with third parties, such as our collaborators. Before obtaining regulatory approval for the commercial distribution of our therapeutic candidates, we or a collaborator must conduct extensive preclinical tests and clinical trials to demonstrate the safety and efficacy in humans of our therapeutic candidates. Preclinical testing and clinical trials are expensive, difficult to design and implement, can take many years to complete, and are uncertain as to outcome. For example, in October 2022, we announced the termination of enrollment of davoceticept clinical studies (NEON-1 and NEON-2) after we were notified of a second death in the NEON-2 study, which investigated davoceticept in combination with pembrolizumab. While we continue to monitor all NEON study participants previously enrolled in the NEON studies, we are currently focused on advancing the development of acazicolcept and ALPN-303; however, even with the significant investment of time and funding to advance these product candidates, we cannot guarantee that our clinical and preclinical development efforts will be successful. The start or end of a clinical study is often delayed or halted due to delays in or failure to obtain regulatory approval to commence the study, delays in or failure to reach agreement on acceptable terms with prospective CROs or clinical trial sites, delays in or failure to obtain IRB approval at each site, changing regulatory requirements, manufacturing challenges, clinical sites or CROs deviating from the trial protocol or failing to comply with regulatory requirements or meet contractual obligations, slower than anticipated patient enrollment, changing standards of care, availability or prevalence of use of a comparative therapeutic or required prior therapy, clinical outcomes, failure of patients to complete the trial or return for post-treatment follow-up, or financial constraints. For instance, delays or difficulties in patient enrollment or difficulties in retaining trial participants can result in increased costs, longer development times, or termination termination of a clinical trial. Clinical trials of a new therapeutic candidate require the enrollment of a sufficient number of patients, which may include patients who are suffering from the disease the therapeutic candidate is intended to treat and who meet other eligibility criteria. Rates of patient enrollment are affected by many factors, including the size of the patient population, the eligibility criteria for the clinical trial, the age and condition of the patients, the stage and severity of disease, the nature of the protocol, the proximity of patients to clinical sites, and the availability of effective treatments or competing academic and other clinical trials for the relevant disease.

A therapeutic candidate can unexpectedly fail at any stage of preclinical and clinical development. The historical failure rate for therapeutic candidates is high due to scientific feasibility, safety, efficacy, changing standards of medical care, and other variables. The novelty of our platform may mean our failure rates are higher than historical norms. The results from preclinical testing or early clinical trials of a therapeutic candidate may not predict the outcome of later phase clinical trials of the therapeutic candidate, particularly in immuno-oncology and autoimmune and inflammatory disorders. We will have to conduct additional trials in our proposed indications to verify the results obtained to date in our preclinical and clinical studies and to support any future regulatory submissions. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles despite promising results in earlier, smaller clinical trials. Moreover, clinical data are often susceptible to varying interpretations and analyses. We do not know whether Phase 1, Phase 2, Phase 3, or other clinical trials we may conduct will demonstrate consistent or adequate efficacy and safety with respect to the proposed indication for use sufficient to receive regulatory approval or market our therapeutic candidates. To the extent that the results of the clinical trials are not satisfactory to the FDA or foreign regulatory authorities for supporting a marketing application, we may be required to expend significant resources, which may not be available to us, to conduct additional clinical trials in support of potential approval of our product candidates.

We, the FDA, an IRB, an independent ethics committee, or other applicable regulatory authorities may suspend clinical trials of a therapeutic candidate at any time for various reasons, including a belief that subjects participating in such trials are being exposed to unacceptable health risks or adverse side effects. Similarly, an IRB or ethics committee may suspend

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a clinical trial at a particular trial site. We may not have the financial resources to continue development of, or to enter into collaborations for, a therapeutic candidate if we experience any problems or other unforeseen events delaying or preventing clinical development or regulatory approval of, or our ability to commercialize, therapeutic candidates, including:

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

•serious and unexpected drug-related side effects experienced by participants in our clinical trials or by individuals using therapeutics similar to our therapeutic candidates;

•serious drug-related side effects experienced in the past by individuals using therapeutics similar to our therapeutic candidates;

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

•conditions imposed by the FDA or comparable foreign authorities, such as the European Medicines Agency, or EMA, regarding the scope or design of our clinical trials;

•delays in enrolling research subjects in clinical trials;

•high drop-out rates of research subjects;

•inadequate supply or quality of therapeutic candidate or therapeutic candidate components, or materials or other supplies necessary for the conduct of our clinical trials, including those owned, manufactured, or provided by companies other than ours;

•greater than anticipated clinical trial costs, including the cost of any approved drugs used in combination with our therapeutic candidates;

•poor effectiveness of our therapeutic candidates during clinical trials;

•unfavorable FDA or other regulatory agency inspection and review of a clinical trial site;

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

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

•varying interpretations of data by the FDA and similar foreign regulatory agencies.

Because we have limited financial and operational resources, we must prioritize our research programs and will need to focus our discovery and development on select product candidates and indications. Correctly prioritizing our research and development activities is particularly important for us due to the breadth of potential product candidates and indications that we intend to utilize with our clinical development strategy. As a result, we may forego or delay pursuit of opportunities with other product candidates or for other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs and product candidates for specific indications may not yield any commercially viable products. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may also relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

Product development involves a lengthy and expensive process with an uncertain outcome, and results of earlier preclinical and clinical trials may not be predictive of future clinical trial results.

Clinical testing is expensive and generally takes many years to complete, and the outcome is inherently uncertain. Failure can occur at any time during the clinical trial process. The results of preclinical trials and early clinical trials of our product candidates may not be predictive of the results of larger, later-stage controlled clinical trials. Product candidates showing promising results in early-stage clinical trials may still suffer significant setbacks in subsequent clinical trials. We have evaluated acazicolcept in a Phase 1 healthy volunteer trial and previously initiated a Phase 1b/2 study of acazicolcept in patients with steroid-resistant or steroid-refractory active acute graft-versus-host disease, or SR-aGVHD. We terminated this Phase 1b/2 SR-aGVHD study in June 2020. Our Phase 2 study in SLE has materially increased our research and development spending and

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we expect this increased spend will continue. SLE is a challenging indication and a number of trials conducted by other companies have failed after significant investment of time and funding. We cannot predict whether our efforts in this indication will be successful. If we are unsuccessful, it is unlikely that AbbVie would exercise its option for acazicolcept pursuant to our option and license agreement and, as a result, we would not receive the option payment pursuant to this agreement and we would not be eligible for future milestones and royalties. In addition, we had initiated our Phase 1 studies of davoceticept, but terminated enrollment in these studies in October 2022 following notification of a second Grade 5 serious adverse event (death) in the NEON-2 study. We will have to conduct additional preclinical studies and human trials in our proposed indications of acazicolcept and ALPN-303 to verify the results obtained to date and to support any regulatory submissions for further clinical development. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles despite promising results in earlier, smaller clinical trials. Moreover, clinical data are often susceptible to varying interpretations and analyses. We do not know whether Phase 1, Phase 2, Phase 3, or other clinical trials we may conduct will demonstrate consistent or adequate efficacy and safety with respect to the proposed indication for use sufficient to receive regulatory approval or market our therapeutic candidates.

Additionally, disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be reviewed by necessary government agencies, which would adversely affect our business. For example, over the last several years, the U.S. government has shut down multiple times and certain regulatory agencies, such as the FDA, have had to furlough critical FDA and other government employees. In response to the COVID-19 public health emergency, since March 2020 when foreign and domestic inspections of facilities were largely placed on hold, the FDA has been working to resume routine surveillance, bioresearch monitoring and pre-approval inspections. In 2020 and 2021, a number of companies announced receipt of complete response letters due to the FDA’s inability to complete required inspections for their applications. While the FDA has largely caught up with domestic preapproval inspections, it continues to work through its backlog of foreign inspections. However, the FDA may not be able to continue its current inspection pace, and review timelines could be extended, including where a pre-approval inspection or an inspection of clinical sites is required and due to the ongoing COVID-19 pandemic and travel restrictions, the FDA is unable to complete such required inspections during the review period. Regulatory authorities outside the U.S. may adopt similar restrictions or other policy measures in response to the COVID-19 pandemic and may experience delays in their regulatory activities. If a prolonged government shutdown or disruption occurs, including due to travel restrictions, foreign COVID-19-related policies, staffing shortages or public health reasons, it could significantly impact the ability of the FDA and other regulatory authorities to timely review and process our regulatory submissions and provide feedback on our clinical development plans, which could have a material adverse effect on our business and our anticipated timelines. Further, future government shutdowns or disruptions to normal operations could impact our ability to access the public markets and obtain necessary capital in order to properly capitalize and continue our operations.

If we encounter delays or difficulties enrolling patients in our clinical trials and/or retention of patients in clinical trials, our clinical development activities could be delayed or otherwise adversely affected.

We may experience difficulties in patient enrollment in our clinical trials for a variety of reasons, including supply chain disruptions, staffing shortages and other business and economic disruptions resulting from geopolitical actions, including war and terrorism, natural disasters, including earthquakes, typhoons, floods and fires, as well as other disruptions resulting from the impact of public health factors, including the COVID-19 pandemic, business disruptions of our strategic partners, third-party manufacturers, suppliers and other third parties upon which we rely. The timely completion of clinical trials in accordance with their protocols depends, among other things, on our ability to enroll a sufficient number of patients who remain in the trial until completion of treatment and adequate follow-up. The enrollment of patients depends on many factors, including:

•Inability to enroll, or delay in enrollment of, patients due to outbreaks and public health crises, such as the COVID-19 global pandemic, as further described under “Risk Factors — Risks Related to COVID-19 and Other Health Epidemics”;

•The patient eligibility criteria defined in the protocol;

•The perceived risks and benefits of the product candidate being studied;

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

•The proximity of patients to trial sites;

•The design of the trial;

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

•Our ability to obtain and maintain patient consent;

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•Geopolitical events in countries where we have or seek to have clinical trial sites;

•Reporting of the preliminary results of any of our clinical trials; and

•The risk that patients enrolled in clinical trials will drop out of the trials before completion of treatment and adequate follow-up.

In addition, our clinical trials will compete with other clinical trials for product candidates that are in the same therapeutic areas as our product candidates, and this competition will reduce the number and types of patients available to us because some patients who might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. Since the number of qualified clinical investigation sites is limited, we expect to conduct some of our clinical trials at the same clinical trial sites that some of our competitors use, which will reduce the number of patients who are available for our clinical trials at such clinical trial sites. Geopolitical events in countries where we have or seek to have clinical trial sites can also negatively impact our ability to enroll patients in our trials. For example, we had intended to open trial sites in Russia for both our ongoing Synergy trial and our planned Phase 2 trial in SLE with ALPN-303. Following the start of the Russia-Ukraine conflict, we abandoned our plans to open these sites. Although no sites in Russia had been opened, we must revise our plans and locate alternative trial sites in order to achieve targeted enrollment numbers and enrollment rates for these trials. Any resulting delays in patient enrollment may increase our costs or may affect the timing or outcome of our ongoing and planned clinical trials, which could prevent completion or commencement of these trials and adversely affect our ability to advance the development of our product candidates.

Our product candidates may cause undesirable side effects or have other properties that could halt their clinical development, prevent their regulatory approval, require expansion of the trial size, limit their commercial potential, or result in significant negative consequences.

Clinical trials that involve cancer patients with significant co-morbidities are associated with increased risks as such participants may be particularly susceptible to safety and toxicity risks. In addition, these side effects may not be appropriately recognized or managed by the treating medical staff, as safety and toxicity monitoring may be complicated and difficult to manage, which could result in patient death or other significant issues. Additionally, it can be difficult to determine if the serious adverse or unexpected side effects were caused by the product candidate or another factors, especially in oncology subjects who may suffer from other medical conditions and take other medications. Such risks are increased in clinical trials that evaluate combination therapies.

If serious adverse events or undesirable side effects arise, we could be required to suspend, delay, or halt our clinical trials. For example, in October 2022 we voluntarily terminated enrollment in both clinical studies involving davoceticept following a second Grade 5 serious adverse event (patient death) in the NEON-2 trial. Additionally, serious adverse events or undesirable side effects could cause regulatory authorities to deny approval or require us to limit development of that product candidate to certain uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. Undesirable side effects could also result in an expansion in the size of our clinical trials, increasing the expected costs and timeline of our clinical trials. Side effects that are observed during the trial, whether treatment related or not, could also affect patient recruitment for future trials or the ability of enrolled patients to complete the trial or result in potential product liability claims.

Further, if serious adverse events or undesirable side effects are identified during development or after approval and are determined to be attributed to any of our product candidates, we may be required to develop Risk Evaluation and Mitigation Strategies, or REMS, to ensure that the benefits of treatment with such product candidate outweigh the risks for each potential patient, which may include, among other things, a communication plan to health care practitioners, patient education, extensive patient monitoring or distribution systems and processes that are highly controlled, restrictive and more costly than what is typical for the industry.

Any of these occurrences may harm our business, financial condition and prospects significantly.

Development of product candidates in combination with other therapies could expose us to additional risks.

Development of any of our product candidates in combination with one or more other therapies that have either been approved or not yet been approved for marketing by the FDA, EMA or comparable foreign regulatory authorities could expose us to additional risks, as combination therapies may increase the rate of serious or unexpected adverse events, which could result in a clinical hold as well as pre-approval and post-approval restrictions by the FDA or other regulatory authorities on the proposed combination therapy, including narrowing of the indication, warnings, additional safety data collection and monitoring procedures, and REMS, even if the cause of such serious or unexpected adverse events are not directly attributed to our product candidate. Any of these events or restrictions could have a material adverse effect on our business, development of our product candidates, delay our regulatory approval, and decrease the market acceptance and profitability of our product

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candidate if approved for a combination therapy. For example, as discussed in the risk factor above, our NEON-2 trial evaluating davoceticept in combination with Merck’s pembrolizumab in adults with advanced malignancies was placed on partial clinical hold by the FDA between March 2022 and May 2022, during which time we were unable to enroll any additional participants in the clinical trial, and was later voluntarily terminated in October 2022 due to safety concerns.

We will not be able to market and sell any product candidate in combination with any unapproved therapies that do not ultimately obtain marketing approval. If the FDA, EMA or other comparable foreign regulatory authorities do not approve or revoke their approval of other therapies used in combination therapies, or if safety, efficacy, commercial adoption, manufacturing or supply issues arise with the therapies we choose to evaluate in combination with any of our product candidate, we may be unable to obtain approval of or successfully market any one or all of the product candidates we develop.

Even if any of our product candidates were to receive marketing approval or be commercialized for use in combination with other existing approved therapies, we would continue to be subject to the risks that the FDA, EMA or other comparable foreign regulatory authorities could revoke approval of the other therapy used in combination with any of our product candidates, or safety, efficacy, manufacturing or supply issues could arise with these existing therapies. In addition, it is possible that existing therapies with which our product candidates are approved for use could themselves fall out of favor or be relegated to later lines of treatment. This could result in the need to identify other combination therapies for our product candidates or our own products being removed from the market or being less successful commercially.

Additionally, if the third-party providers of therapies or therapies in development used in combination with our product candidates are unable to produce sufficient quantities for clinical trials or for commercialization of our product candidates, or if the cost of combination therapies is prohibitive, our development and commercialization efforts would be impaired, which would have an adverse effect on our business, financial condition, results of operations and growth prospects.

We face competition from entities that have developed or may develop therapeutic candidates for our target disease indications, including companies developing novel treatments and technology platforms based on modalities and technology similar to us.

We participate in the highly competitive sector of biotechnology and pharmaceuticals and in the subsector of immune modulation. This subsector has undergone tremendous technological advancement over the last decade due to advancements in understanding the role of the immune system across multiple therapeutic areas, including oncology and autoimmune and inflammatory disease. While we believe our novel technology platform, discovery programs, knowledge, experience, and scientific resources offer competitive advantages, we face competition from major pharmaceutical and biotechnology companies, academic institutions, governmental agencies, public and private research institutions, and others.

Any products we successfully develop and commercialize will face competition from currently approved therapies and new therapies potentially available in the future.

The availability of reimbursement from government and other third-party payors will also significantly affect the pricing and competitiveness of our products. Our competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for our products, which could result in our competitors establishing a strong market position before we are able to enter the market.

Many of the companies we compete against may have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals, and marketing approved products. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs. If these companies develop technologies or therapeutic candidates more rapidly than we do, or their technologies, including delivery technologies, are more effective, our ability to develop and successfully commercialize therapeutic candidates may be adversely affected. For additional information regarding our competitors and the competitive landscape, please refer to the section of our Annual Report on Form 10-K for the year ended December 31, 2021 titled “Business—Competition.”

Many of our competitors have significantly greater financial, technical, manufacturing, marketing, sales, and supply resources or experience than we have. If we successfully obtain approval for any therapeutic candidate, we will face competition based on many different factors, including safety and effectiveness, ease with which our products can be administered and the extent to which patients accept relatively new routes of administration, timing and scope of regulatory approvals, availability and cost of manufacturing, marketing and sales capabilities, price, reimbursement coverage, and patent position of our products. Competing products could present superior treatment alternatives, including by being more effective, safer, less expensive, or marketed and sold more effectively than any products we may develop. Competitive products may make any products we develop obsolete or noncompetitive before we recover the expense of developing and commercializing

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our therapeutic candidates. Competitors could also recruit our employees, which could negatively impact our ability to execute our business plan.

We believe our development programs and platform have a particular mechanism of action, but this mechanism of action has not been proven conclusively.

Our scientific platform is novel, and the underlying science is not exhaustively understood nor conclusively proven. In particular, the interaction of vIgDs with the immune synapse, the ability of vIgDs to slow, stop, restart, or accelerate immune responses, and the ability of vIgD domains to interact with multiple counter structures is still largely theoretical. Graphical representations of proposed mechanisms of action of our therapies, the size, actual or relative, of our therapeutics, and how our therapeutics might interface with other cells within the human body, inside the immune synapse, or inside the disease and/or the tumor microenvironment are similarly theoretical and not yet conclusively proven. The lack of a proven mechanism of action may adversely affect our ability to raise sufficient capital, complete preclinical studies, adequately manufacture drug product, obtain regulatory clearance for clinical trials, gain marketing approval, or conclude collaborations, or interfere with our ability to market our product to patients and physicians or achieve reimbursement from payors.

Any inability to present our data in scientific journals or at scientific conferences could adversely impact our business and stock price.

We may from time to time submit data related to our research and development activities in peer-reviewed scientific publications or apply to present data related to our research and development activities at scientific or other conferences. We have no control over whether these submissions or applications are accepted. Even if accepted for a conference, we have no control over whether presentations at scientific conferences will be accepted for oral presentation, poster presentation, or abstract publication only. Even when accepted for publication, we have no control over the timing of the release of the publication. Rejection by publications, delays in publication, rejection for presentation, or a less-preferred format for a presentation may adversely impact our stock price, ability to raise capital, and business.

Our business may be affected by adverse scientific publications or editorial or discussant opinions.

We may from time to time publish data related to our research and development activities in peer-reviewed scientific publications or present data related to our research and development activities at scientific or other conferences. Editorials or discussants unrelated to us may provide opinions on our presented data unfavorable to us. In addition, scientific publications or presentations may be made which are critical of our science or research or the field of immunotherapy in general. This may adversely affect our ability to raise necessary capital, complete clinical and preclinical studies, adequately manufacture drug product, obtain regulatory clearance for clinical trials, or approval for marketing, or interfere with our ability to market our product to patients and physicians or achieve reimbursement from payors.

Risks Related to Our Relationships with Third Parties

To date, our revenue has been primarily derived from our collaboration agreements, and our success will be dependent, in part, on our collaborators’ efforts to develop our therapeutic candidates.

Our success is dependent, in part, on our collaborators’ efforts to develop our therapeutic candidates and, historically, our revenue has been primarily derived from our agreements with collaborators. For example, in June 2020, we entered into the AbbVie Agreement for the development of acazicolcept and, in December 2021, we entered into the Horizon Agreement pursuant to which we granted to Horizon rights to one of our existing preclinical biologic therapeutic programs and we and Horizon agreed to collaborate in the discovery, research and preclinical development of up to three additional autoimmune and inflammatory disease programs for other designated biological targets.

Pursuant to the terms of the AbbVie Agreement, we received an upfront payment of $60.0 million in cash and are eligible to receive up to $75.0 million in development milestones (of which $45.0 million was achieved in the second quarter of 2021), an additional $75.0 million if AbbVie exercises its option with respect to acazicolcept following our completion of certain development activities, additional development, commercial and sales-based milestones up to an aggregate of $655.0 million and royalties on any future net sales. Through September 30, 2022, we have received $105.0 million in upfront and pre-option exercise development milestones as part of the AbbVie Agreement.

Pursuant to the AbbVie Agreement, we will conduct certain development activities under a development plan that provides for, among other things, the generation of a data package in order for AbbVie to evaluate exercising its exclusive option, including all activities reasonably necessary to complete our Phase 2 study of acazicolcept in SLE. Even if we

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successfully complete these activities, AbbVie may not exercise its option, which would make achievement of future milestones and receipt of future royalties unattainable. If AbbVie exercises its option, our realization of additional milestones and royalty payments will depend upon the efforts of AbbVie. If AbbVie fails to develop, obtain regulatory approval for, or ultimately commercialize acazicolcept or if AbbVie terminates the collaboration, our business, financial condition, results of operations, and prospects could be materially and adversely affected. For additional information regarding the AbbVie Agreement, please refer to the section of our Annual Report on Form 10-K for the year ended December 31, 2021 titled “Business—Partnerships.”

Pursuant to the terms of the Horizon Agreement, we received an upfront payment of $25.0 million as well as an equity investment for which they paid $15.0 million. We are also eligible to receive milestone payments upon our achievement of certain preclinical, clinical and regulatory and commercialization milestones, up to an aggregate amount of $381.0 million per program, or approximately $1.5 billion in total, if all milestones are met, as well as royalties on future product sales. Pursuant to the Horizon Agreement, we will conduct certain research activities under a research program; however, even if we successfully perform our obligations under the Horizon Agreement, there is no certainty that Horizon will continue the development of any of the programs, or, if development is continued, if such programs will ultimately succeed and receive regulatory approval. Horizon will have discretion in determining and directing its efforts and resources for future development activities and, if approval is obtained, commercialization and marketing of the approved drug. As a result, there can be no assurances that we will achieve additional milestones pursuant to the Horizon Agreement. For additional information regarding the Horizon Agreement, please refer to the section of our Annual Report on Form 10-K for the year ended December 31, 2021 titled “Business—Partnerships.”

Our collaborations may also result in reduced royalty revenues if we are unable to obtain and maintain patent protection, as well as if we are unable to obtain patent term extension, for therapeutic candidates or products developed under our agreements with collaborators. In the event of expiration or invalidation of patents covering a therapeutic candidate or product, for example, our collaborators may be entitled to a significant decrease in royalty revenues owed to us under the agreements. Invalidation of patents and failure to obtain patent term extension for one or more patents in our portfolio may occur as a result of factors beyond our control due to the complex legal and factual questions surrounding pharmaceutical and biotechnology patents. If we are unable to obtain and maintain patent protection, or if we unable to obtain patent term extension for therapeutic candidates or products developed under our agreements with collaborators, our revenue derived from our collaborators may be less than the full amount anticipated, and our business, financial condition, results of operations, and growth prospects could be materially harmed.

Continued advancement of our other product candidates and other development efforts depends, in part, upon the efforts of AbbVie, Horizon, and our other current or future collaborators. If our collaborators do not dedicate sufficient resources to the development of product candidates that are the subject of our agreements, such product candidates may never be successful and we may be ineligible to receive additional milestone payments or royalties pursuant to the terms of our arrangements, which could have a material adverse impact on our financial results and operations. Even if we and our collaborators dedicate sufficient resources to our collaboration agreements, neither we nor our collaborators may be effective in obtaining approvals for any therapeutic candidates or, if approved, the successful commercialization of any approved products. Collaborators may change their strategic focus or pursue alternative technologies after entering into a collaboration agreement with us, which could result in reduced, delayed or no revenue to us. Disputes regarding collaboration agreements, including disputes pertaining to ownership of intellectual property, may also arise and if we and our collaborators are unable to resolve such disputes, litigation proceedings may occur, which could further delay development programs, create uncertainty as to ownership of intellectual property rights, distract management from other business activities and generate substantial expenses, any of which could materially and negatively impact our business.

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If third parties on which we depend to conduct our clinical or preclinical studies, or any future clinical trials, do not perform as expected, fail to satisfy regulatory or legal requirements, or miss expected deadlines, our development program could be delayed, which may result in materially adverse effects on our business, financial condition, results of operations, and prospects.

We rely, in part, on third-party clinical investigators, CROs, clinical data management organizations, and consultants to design, conduct, supervise, and monitor clinical trials and preclinical studies of our therapeutic candidates and may do the same for future clinical trials. Because we rely on third parties to conduct preclinical studies or clinical trials, we have less control over the timing, quality, compliance, and other aspects of preclinical studies and clinical trials than we would if we conducted all preclinical studies and clinical trials on our own. These investigators, CROs, and consultants are not our employees and we have limited control over the amount of time and resources they dedicate to our programs. These third parties may have contractual relationships with other entities, some of which may be our competitors, which may draw their time and resources away from our programs. The third parties with which we contract might not be diligent, careful, compliant, or timely in conducting our preclinical studies or clinical trials, resulting in the preclinical studies or clinical trials being delayed or unsuccessful. Further, if any of our relationships with third-party CROs terminate, we may not be able to enter into arrangements with alternative CROs or to do so on commercially reasonable terms.

If we cannot contract with acceptable third parties on commercially reasonable terms, or at all, or if these third parties do not carry out their expected duties, satisfy legal and regulatory requirements for the conduct of preclinical studies or clinical trials, or meet expected deadlines, our clinical development programs could be delayed and otherwise adversely affected. In all events, we are responsible for ensuring each of our preclinical studies and clinical trials is conducted in accordance with the general investigational plan and protocols for the trial and with legal, regulatory and scientific standards. The FDA and certain foreign regulatory authorities, such as the EMA, require preclinical studies to be conducted in accordance with applicable Good Laboratory Practices, or GLPs, and clinical trials to be conducted in accordance with applicable FDA regulations and Good Clinical Practices, or GCPs, including requirements for conducting, recording, and reporting the results of preclinical studies and clinical trials to assure data and reported results are credible and accurate and the rights, integrity, and confidentiality of clinical trial participants are protected. Our reliance on third parties we do not control does not relieve us of these responsibilities and requirements. If we or any of our CROs fail to comply with applicable GCPs, the clinical data generated in our clinical trials may be deemed unreliable and the FDA, the EMA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials comply with GCP regulations. In addition, our clinical trials must be conducted with product produced under cGMP regulations. Our failure to comply with these regulations may require us to repeat clinical trials, which would delay the regulatory approval process. Any such event could have a material adverse effect on our business, financial condition, results of operations, and prospects.

In addition, switching or adding additional CROs involves additional cost and requires management time and focus. There is also a natural transition period when a new CRO commences work. As a result, delays may occur, which could materially impact our ability to meet our desired clinical development timelines. There can be no assurance that we will not encounter such challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our business, financial condition and prospects.

Because we rely on third-party manufacturing and supply partners, our supply of clinical trial materials may become limited or interrupted or may not be of satisfactory quantity or quality, and our dependence on these third parties may impair the advancement of our research and development programs.

We have established in-house recombinant protein generation capabilities for producing sufficient protein materials to enable a portion of our current preclinical studies. We rely on third-party supply and manufacturing partners to supply the materials, components, and manufacturing services for a portion of preclinical studies and also rely on such third parties for all our clinical trial drug supplies. We do not own manufacturing facilities or supply sources for such components and materials for clinical trial supplies and our current manufacturing facilities are insufficient to supply such components and materials for all of our preclinical studies. Certain raw materials necessary for the manufacture of our therapeutic products, such as cell lines, are available from a single or limited number of source suppliers on a purchase order basis. There can be no assurance our supply of research and development, preclinical study, and clinical trial drugs and other materials will not be limited, interrupted, restricted in certain geographic regions, of satisfactory quality or quantity, or continue to be available at acceptable prices. In particular, any replacement of our therapeutic substance manufacturer could require significant effort and expertise and could result in significant delay of our preclinical or clinical activities because there may be a limited number of qualified replacements. In addition, disruptions to ports and other shipping infrastructure, due in part to the impact of the ongoing COVID-19 pandemic, may result in shortages or delays impacting the availability of materials and other supplies, which could negatively impact our manufacturers, suppliers and other third parties on whom we rely. While we have not yet suffered any

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direct, material negative impacts from these ongoing supply chain disruptions, we cannot be certain that we will not be impacted, which could increase our costs or negatively impact our development timelines.

The manufacturing process for a therapeutic candidate is subject to FDA and foreign regulatory authority review, and the facilities used by our contract manufacturers to manufacture our therapeutic candidates must be approved by the FDA pursuant to inspections that will be conducted after we submit our marketing application(s) to the FDA. Suppliers and manufacturers must meet applicable manufacturing requirements and undergo rigorous facility and process validation tests required by regulatory authorities in order to comply with cGMP regulations or other regulatory standards. In the event any of our suppliers or manufacturers fails to comply with such requirements or to perform its obligations to us in relation to quality, timing, or otherwise, or if our supply of components or other materials becomes limited or interrupted for other reasons, we may experience shortages resulting in delayed shipments, supply constraints, and/or stock-outs of our products, be forced to manufacture the materials alone, for which we currently do not have the capabilities or resources, or enter into an agreement with another third party, which we may not be able to do on reasonable terms, if at all. In some cases, the technical skills or technology required to manufacture our therapeutic candidates may be unique or proprietary to the original manufacturer and we may have difficulty, or there may be contractual and intellectual property restrictions prohibiting us from, transferring such skills or technology to another third party and a feasible alternative may not exist. These factors may increase our reliance on such manufacturer or require us to obtain a license from such manufacturer in order to have another third party manufacture our therapeutic candidates. If we are required to change manufacturers for any reason, we will be required to verify the new manufacturer maintains facilities and procedures complying with quality standards and with all applicable regulations. The delays associated with the verification of a new manufacturer could negatively affect our ability to develop therapeutic candidates in a timely manner, within budget, or at all.

We expect to continue to rely on third-party manufacturers if we receive regulatory approval for any therapeutic candidate. To the extent we have existing, or enter into future, manufacturing arrangements with third parties, we will depend on these third parties to perform their obligations in a timely manner consistent with contractual and regulatory requirements, including those related to quality control and assurance. If we are unable to obtain or maintain third-party manufacturing for therapeutic candidates, or to do so on commercially reasonable terms, we may not be able to develop and commercialize our therapeutic candidates successfully. Our, or a third party’s, failure to execute on our manufacturing requirements could adversely affect our business in a number of ways, including as a result of:

•an inability to initiate or continue preclinical studies or clinical trials of therapeutic candidates under development;

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

•the loss of the cooperation of a collaborator;

•subjecting manufacturing facilities of our therapeutic candidates to additional inspections by regulatory authorities;

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

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

As product candidates progress from preclinical studies to late-stage clinical trials to marketing approval and commercialization, it is common that various aspects of the development program, such as manufacturing methods, materials and processes, are altered along the way in an effort to optimize yield, manufacturing batch size, minimize costs and achieve consistent purity, identity, potency, quality and results. Such changes carry the risk that they will not achieve these intended objectives. Any of these changes could cause our product candidates to perform differently and could affect planned or other clinical trials conducted with product candidates produced using the modified manufacturing methods, materials, and processes. This could delay completion of clinical trials and could require non-clinical or clinical bridging and comparability studies, which could increase costs, delay approval of our product candidates and jeopardize our ability to commercialize our product candidates, if approved.

We may not successfully engage in strategic transactions, including any additional collaborations we seek, which could adversely affect our ability to develop and commercialize therapeutic candidates, impact our cash position, increase our expenses, and present significant distractions to our management.

From time to time, we consider strategic transactions, such as collaborations, acquisitions of companies, asset purchases or divestitures, and out- or in-licensing of therapeutic candidates or technologies. In particular, we intend to evaluate and, if strategically attractive, seek to enter into additional collaborations, including with major biotechnology or pharmaceutical companies. The competition for collaborative partners is intense, and the negotiation process is time-consuming and complex. Any new collaboration may be on suboptimal terms for us, and ultimately may not maximize value for our

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stockholders. In addition, we may be unable to maintain any new or existing collaboration if, for example, development or approval of a therapeutic candidate is delayed, sales of an approved therapeutic product do not meet expectations, or the collaborator terminates the collaboration. Any such collaboration, or other strategic transaction, may require us to incur non-recurring or other charges, increase our near- and long-term expenditures and pose significant integration or implementation challenges or disrupt our management or business.

These transactions would entail numerous operational and financial risks, including:

•exposure to unknown liabilities;

•disruption of our business and diversion of our management’s time and attention in order to manage a collaboration or develop acquired therapeutic candidates, or technologies;

•incurrence of substantial debt or dilutive issuances of equity securities to pay transaction consideration or costs;

•higher than expected collaboration, acquisition, or integration costs;

•write-downs of assets, or incurring impairment charges or increased amortization expenses; and

•difficulty and cost in facilitating the collaboration or combining the operations and personnel of any acquired business or impairment of relationships with key suppliers, manufacturers, or customers of any acquired business due to changes in management and ownership and the inability to retain key employees of any acquired business.

Accordingly, although there can be no assurance we will undertake or successfully complete any transactions of the nature described above, any transactions we do complete may be subject to the foregoing or other risks and have a material adverse effect on our business, results of operations, financial condition, and prospects. Conversely, any failure to enter any collaboration or other strategic transaction beneficial to us could delay the development and potential commercialization of our therapeutic candidates and have a negative impact on the competitiveness of any therapeutic candidate reaching market.

Risks Related to Our Ability to Commercialize Product Candidates

If any of our therapeutic candidates are approved for marketing and commercialization and we are unable to develop sales, marketing and distribution capabilities on our own or enter into agreements with third parties to perform these functions on acceptable terms, we may be unable to successfully commercialize any such future products.

We currently have no sales, marketing, or distribution capabilities or experience. If any of our therapeutic candidates are approved, we will need to develop internal sales, marketing, and distribution capabilities to commercialize such products, which may be expensive and time-consuming, or enter into collaborations with third parties to perform these services. If we decide to market our products directly, we will need to commit significant financial, legal, and managerial resources to develop a marketing and sales force with technical expertise and supporting distribution, administration, and compliance capabilities. If we rely on third parties with such capabilities to market our approved products, or decide to co-promote products with collaborators, we will need to establish and maintain marketing and distribution arrangements with third parties, and there can be no assurance we will be able to enter into such arrangements on acceptable, compliant terms or at all. In entering into third-party marketing or distribution arrangements, any revenue we receive will depend upon the efforts of the third parties and there can be no assurance such third parties will establish adequate sales and distribution capabilities or be successful in gaining market acceptance of any approved therapeutic. If we are not successful in commercializing any therapeutic approved in the future, either on our own or through third parties, our business, financial condition, results of operations, and prospects could be materially and adversely affected.

If we fail to comply with U.S. and foreign regulatory requirements, regulatory authorities could limit or withdraw any marketing or commercialization approvals we may receive and subject us to other penalties that could materially harm our business.

Our company, our therapeutic candidates, our suppliers, and our contract manufacturers, distributors, and contract testing laboratories are subject to extensive regulation by governmental authorities in the European Union, the United States, and other countries, with regulations differing from country to country.

Even if we receive marketing and commercialization approval of a therapeutic candidate, we and our third-party service providers will be subject to continuing regulatory requirements, including a broad array of regulations related to establishment registration and product listing, manufacturing processes, risk management measures, quality and pharmacovigilance systems, post-approval clinical studies, labeling and packaging, advertising and promotional activities, record keeping, distribution, adverse event reporting, import and export of pharmaceutical products, pricing, sales, and marketing, and fraud and abuse requirements.

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Furthermore, the FDA strictly regulates manufacturers’ promotional claims of drug products. In particular, a drug product may not be promoted by manufacturers for uses that are not approved by the FDA, as reflected in the FDA-approved labeling, although healthcare professionals are permitted to use drug products for off-label uses. The FDA, the Department of Justice, the Inspector General of the Department of Health and Human Services, among other government agencies, actively enforce the laws and regulations prohibiting manufacturers’ promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability, including large civil and criminal fines, penalties, and enforcement actions. The FDA has also imposed consent decrees or permanent injunctions under which specified promotional conduct is changed or curtailed for companies that engaged in such prohibited activities. If we cannot successfully manage the promotion of our approved product candidates, we could become subject to significant liability, which would materially adversely affect our business and financial condition.

We are required to submit safety and other post market information and reports, and are subject to continuing regulatory review, including in relation to adverse patient experiences with the product and clinical results reported after a product is made commercially available, both in the United States and in any foreign jurisdiction in which we seek regulatory approval. The FDA and certain foreign regulatory authorities, such as the EMA, have significant post-market authority, including the authority to require labeling changes based on new safety information and to require post-market studies or clinical trials to evaluate safety risks related to the use of a product or to require withdrawal of the product from the market.

The FDA also has the authority to require a REMS plan either before or after approval, which may impose further requirements or restrictions on the distribution or use of an approved therapeutic. The EMA now routinely requires risk management plans, or RMPs, as part of the marketing authorization application process, and such plans must be continually modified and updated throughout the lifetime of the product as new information becomes available. In addition, the relevant governmental authority of any EU member state can request an RMP whenever there is a concern about the risk/benefit balance of the product.

The manufacturers and manufacturing facilities we use to make a future product, if any, will also be subject to periodic review and inspection by the FDA and other regulatory agencies, including for continued compliance with cGMP requirements. The discovery of any new or previously unknown problems with our third-party manufacturers, manufacturing processes or facilities may result in restrictions on the product, manufacturers or facilities, including withdrawal of the product from the market. If we rely on third-party manufacturers, we will have limited control over compliance with applicable rules and regulations by such manufacturers.

If we or our collaborators, manufacturers, or service providers fail to comply with applicable continuing regulatory requirements in the U.S. or foreign jurisdictions in which we seek to market our products, we may be subject to, among other things, fines, warning and untitled letters, clinical holds, a requirement to conduct additional clinical trials, delay or refusal by the FDA or foreign regulatory authorities to approve pending applications or supplements to approved applications, suspension, refusal to renew or withdrawal of regulatory approval, product recalls, seizures, or administrative detention of products, refusal to permit the import or export of products, operating restrictions, inability to participate in government programs including Medicare and Medicaid, and total or partial suspension of production or distribution, injunction, restitution, disgorgement, debarment, civil penalties, and criminal prosecution.

Imposed price controls may adversely affect our future profitability.

In most countries, the pricing of prescription drugs is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after receipt of marketing approval for a product. In addition, there can be considerable pressure by governments and other stakeholders on prices and reimbursement levels, including as part of cost containment measures. Political, economic, and regulatory developments may further complicate pricing and reimbursement negotiations, and pricing negotiations may continue after reimbursement has been obtained.

Reference pricing used by various EU member states and parallel distribution, or arbitrage between low-priced and high-priced member states, can further reduce prices. In some countries, we or our collaborators may be required to conduct a clinical trial or other studies comparing the cost-effectiveness of our therapeutic candidates to other available therapies in order to obtain or maintain reimbursement or pricing approval. Publication of discounts by third-party payors or authorities may lead to further pressure on the prices or reimbursement levels within the country of publication and other countries. If reimbursement of any product candidate approved for marketing is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business, financial condition, results of operations, or prospects could be adversely affected.

Our business may become subject to economic, political, regulatory and other risks associated with international operations.

Our business is subject to risks associated with conducting business internationally, including our use of foreign clinical trial sites. Some of our suppliers, collaborators and clinical trial relationships are located outside the United States.

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Accordingly, our future results could be harmed by a variety of factors, including:

•economic instability or weakness, including inflation, reduced growth, diminished credit availability, weakened consumer confidence or increased unemployment;

•sociopolitical instability in particular foreign economies and markets;

•difficulties in compliance with non-U.S. laws and regulations;

•changes in non-U.S. regulations and customs, tariffs and trade barriers, including any changes that China may impose as a result of political tensions between the United States and China;

•changes in non-U.S. currency exchange rates and currency controls;

•trade protection measures, import or export licensing requirements or other restrictive actions by U.S. or non-U.S. governments;

•workforce uncertainty in countries where labor unrest is more common than in the United States;

•production shortages resulting from any events affecting raw material supply or manufacturing capabilities outside the United States;

•business interruptions resulting directly or indirectly from geopolitical actions, including the Russia-Ukraine conflict, other regional conflicts, war and terrorism, or natural disasters including earthquakes, typhoons, floods and fires; and

•changes in regulatory requirements and policies that apply to our business, including changes in the regulatory approval process, clinical trial requirements, data standards, and export regulations and controls.

Risks Related to Our Personnel and Operations

We will need to raise substantial additional funds to advance development of our therapeutic candidates, and we cannot guarantee we will have sufficient funds available in the future to develop and commercialize our current or future therapeutic candidates.

We will need to raise substantial additional funds to expand our development, regulatory, manufacturing, marketing, and sales capabilities or contract with other organizations to provide these capabilities to us. We have used substantial funds to develop our therapeutic candidates and will require significant funds to conduct further research and development, preclinical testing, and clinical trials of our therapeutic candidates, to seek regulatory approvals for our therapeutic candidates, and to manufacture and market products, if any are approved for commercial sale. As of September 30, 2022, we had $277.1 million in cash and cash equivalents, restricted cash, and investments. Based on our current operating plan, we believe our available cash and cash equivalents and investments will be sufficient to fund our planned level of operations, including anticipated capital expenditures, for at least the next 12 months. Our future capital requirements and the period for which we expect our existing resources to support our operations may vary significantly from what we expect. Our monthly spending levels vary based on new and ongoing development and corporate activities. Because the length of time and activities associated with successful development of our therapeutic candidates are highly uncertain, we are unable to estimate the actual funds we will require for development and any approved marketing and commercialization activities. To execute our business plan, we will need, among other things:

•to obtain the human and financial resources necessary to develop, test, obtain regulatory approval for, manufacture, and market our therapeutic candidates;

•to build and maintain a strong intellectual property portfolio and avoid infringing intellectual property of third parties;

•to establish and maintain successful licenses, collaborations, and alliances;

•to satisfy the requirements of clinical trial protocols, including patient enrollment;

•to establish and demonstrate the clinical efficacy and safety of our therapeutic candidates;

•to obtain regulatory approvals;

•to manage our spending as costs and expenses increase due to preclinical studies, clinical trials, regulatory approvals, manufacturing scale-up, and commercialization;

•to obtain additional capital to support and expand our operations; and

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•to market our products to achieve acceptance and use by the medical community in general.

If we are unable to obtain necessary funding on a timely basis or on acceptable terms, we may have to delay, reduce, or terminate our research and development programs, preclinical studies, or clinical trials, if any, limit strategic opportunities, or undergo reductions in our workforce or other corporate restructuring activities. We also could be required to seek funds through arrangements with collaborators or others requiring us to relinquish rights to some of our technologies or therapeutic candidates we would otherwise pursue on our own. We do not expect to realize revenue from product sales, or royalties in the foreseeable future, if at all. Our revenue sources are, and will remain, extremely limited unless and until our therapeutic candidates are clinically tested, approved for commercialization, and successfully marketed.

To date, we have financed our operations primarily through the sale of equity securities, debt, and payments received under our collaboration agreements. We will be required to seek additional funding in the future and intend to do so through a combination of public or private equity offerings, debt financings, credit and loan facilities, research collaborations, and license agreements. Our ability to raise additional funds from these or other sources will depend on financial, economic, and other factors, many of which are beyond our control. Additional funds may not be available to us on acceptable terms or at all.

If we raise additional funds by issuing equity securities, our stockholders will suffer dilution, and the terms of any financing may adversely affect the rights of our stockholders. For example, in January 2019, we issued in a private placement 4,706,700 shares of common stock and warrants to purchase an additional 1,835,610 shares of common stock for gross proceeds of approximately $25.3 million. In July 2020, we issued in a private placement 5,139,610 shares of common stock, prefunded warrants to purchase 790,710 shares of common stock and warrants to purchase an additional 1,779,096 shares of common stock for gross proceeds of approximately $60.0 million. In September 2021, we issued in a private placement 6,489,357 shares of common stock and prefunded warrants to purchase an additional 3,191,487 shares of common stock for gross proceeds of approximately $91.0 million. In December 2021, in connection with the Horizon Agreement, we sold 951,980 shares of our common stock to Horizon for which they paid $15.0 million. In September 2022, we issued in an underwritten public offering 13,606,000 shares of common stock for net proceeds of approximately $93.5 million, after deducting underwriting discounts, commissions and offering expenses, and we issued an additional 1,903,282 shares of common stock in October 2022 pursuant to the underwriters’ partial exercise of their over-allotment option, for net proceeds of approximately $13.1 million. From time to time, we also have entered into “at the market” equity offering arrangements that enable us to sell shares of our common stock from time to time through an “at the market” equity offering. In September 2022, we terminated our “at the market” equity offering arrangement with Cowen and Company, LLC in connection with our September 2022 underwritten offering, but we may in the future implement similar “at the market” equity offering arrangements.

In addition, as a condition to providing additional funds to us, future investors may demand, and may be granted, rights superior to those of existing stockholders. Debt financing, if available, may involve restrictive covenants limiting our flexibility in conducting future business activities, and, in the event of a liquidation or insolvency, debt holders would be repaid before holders of equity securities receive any distribution of corporate assets. Our failure to raise capital or enter into such other arrangements within a reasonable timeframe would have a negative impact on our financial condition, and we may have to delay, reduce, or terminate our research and development programs, preclinical or clinical trials, or undergo reductions in our workforce or other corporate restructuring activities.

We are an early stage biopharmaceutical company with a history of losses, we expect to continue to incur significant losses for the foreseeable future, we may never achieve or maintain profitability, and we have a limited operating history that may make it difficult for investors to evaluate the potential success of our business.

We are a clinical-stage immunotherapy company, with a limited operating history, focused on developing treatments for autoimmune and inflammatory diseases. Since inception, we have devoted our resources to developing novel protein-based immunotherapies primarily using our proprietary directed evolution platform, which converts native immune system proteins into potential differentiated, multi-targeted therapeutics designed to modulate the immune system. We have had significant operating losses since inception. For the nine months ended September 30, 2022, our net loss was $38.9 million. Substantially all of our losses have resulted from expenses incurred in connection with our research programs and from general and administrative costs associated with our operations. In addition, inflationary pressure could adversely impact our financial results. Our operating costs have increased, and may continue to increase, due to the recent growth in inflation. Our technologies and therapeutic candidates are in early stages of development, and we are subject to the risks of failure inherent in the development of therapeutic candidates based on novel technologies.

We have historically generated revenue primarily from the receipt of research funding and upfront and other payments under our collaboration agreements. We have not generated, and do not expect to generate, any revenue from product sales for the foreseeable future, and we expect to continue to incur significant operating losses for the foreseeable future due to the cost of research and development, preclinical studies, clinical trials, and the regulatory approval process for therapeutic candidates. The amount of future losses is uncertain. Our ability to achieve profitability, if ever, will depend on, among other things, our or

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our existing collaborators, or any future collaborators, successfully developing therapeutic candidates, obtaining regulatory approvals to market and commercialize therapeutic candidates, manufacturing any approved products on commercially reasonable terms, establishing a sales and marketing organization or suitable third-party alternatives for any approved product, and raising sufficient funds to finance business activities. If we or our existing collaborators, or any future collaborators, are unable to develop and commercialize one or more of our therapeutic candidates or if sales revenue from any therapeutic candidate receiving approval is insufficient, we will not achieve profitability, which could have a material adverse effect on our business, financial condition, results of operations, and prospects.

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

From time to time, we may publish interim, preliminary or topline data from clinical trials. Interim data from clinical trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Interim or preliminary data from clinical trials that we may conduct may not be indicative of the final results of the trial and are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data becomes available. Interim or preliminary data also remains subject to audit and verification procedures that may result in the final data being materially different from the interim or preliminary data. As a result, interim or preliminary data should be viewed with caution until the final data are available. Adverse differences between interim, preliminary or topline data and final data could significantly harm our reputation and business prospects. We do not know whether any clinical trials we may conduct will demonstrate consistent or adequate efficacy and safety sufficient to obtain marketing approval to market our product candidates.

Moreover, preliminary, interim and topline data are subject to the risk that one or more of the clinical outcomes may materially change as more patient data become available when patients mature on study, patient enrollment continues or as other ongoing or future clinical trials with a product candidate further develop. Past results of clinical trials may not be predictive of future results. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is based on what is typically more extensive information, and you or others may not agree with what we determine is the material or otherwise appropriate information to include in our disclosure. Any information we determine not to disclose may ultimately be deemed significant with respect to future decisions, conclusions, views, activities or otherwise regarding a particular product candidate or our business. Similarly, even if we are able to complete our planned and ongoing preclinical studies and clinical trials of our product candidates according to our current development timeline, the positive results from such preclinical studies and clinical trials of our product candidates may not be replicated in subsequent preclinical studies or clinical trial results. Moreover, preclinical, nonclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that believed their product candidates performed satisfactorily in preclinical studies and clinical trials nonetheless failed to obtain FDA or other regulatory approval.

Any inability to attract and retain qualified key management and technical personnel would impair our ability to implement our business plan.

Our success largely depends on the continued service of key management and other specialized personnel, including Mitchell H. Gold, M.D., our Executive Chairman and Chief Executive Officer, Stanford Peng, M.D., Ph.D., our President and Head of Research and Development, and Paul Rickey, our Senior Vice President and Chief Financial Officer.

The loss of one or more members of our management team or other key employees or advisors could delay our research and development programs and materially harm our business, financial condition, results of operations, and prospects. The relationships our key managers have cultivated within our industry make us particularly dependent upon their continued employment with us. We are dependent on the continued service of our technical personnel because of the highly technical nature of our therapeutic candidates and technologies, and the specialized nature of the regulatory approval process. Because our management team and key employees are not obligated to provide us with continued service, they could terminate their employment with us at any time without penalty. We do not maintain key person life insurance policies on any of our management team members or key employees. Our future success will depend in large part on our continued ability to attract and retain other highly qualified scientific, technical, and management personnel, as well as personnel with expertise in clinical testing, manufacturing, governmental regulation, and commercialization. We face competition for personnel from other companies, universities, public and private research institutions, government entities, and other organizations, including significant competition in the Seattle employment market.

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As our therapeutic candidates advance into clinical trials, we may experience difficulties in managing our growth and expanding our operations.

We have limited experience in therapeutic development and very limited experience with clinical trials of therapeutic candidates. As our therapeutic candidates enter and advance through preclinical studies and clinical trials, we will need to expand our development, regulatory, and manufacturing capabilities or contract with other organizations to provide these capabilities for us. For example, as we continue enrollment in our Phase 2 study in SLE and continue with the development of our other product candidates, we will need to hire additional personnel in clinical operations. We also must manage relationships with collaborators or partners, suppliers, and other organizations. Our ability to manage our operations and future growth will require us to continue to improve our operational, financial, and management controls, reporting systems, and procedures. We may not be able to implement improvements to our management information and control systems in an efficient or timely manner and may discover deficiencies in existing systems and controls.

Our business entails a significant risk of product liability and our inability to obtain sufficient insurance coverage could harm our business, financial condition, results of operations, or prospects.

Our business exposes us to significant product liability risks inherent in the development, testing, manufacturing, and marketing of therapeutic treatments. Product liability claims could delay or prevent completion of our development programs. If we succeed in marketing products, such claims could result in an investigation by certain regulatory authorities, such as FDA or foreign regulatory authorities, of the safety and effectiveness of our products, our manufacturing processes and facilities, or our marketing programs and potentially a recall of our products or more serious enforcement action, limitations on the approved indications for which they may be used, or suspension or withdrawal of approvals. Regardless of the merits or eventual outcome, liability claims may also result in decreased demand for our products, injury to our reputation, costs to defend the related litigation, a diversion of management’s time and our resources, substantial monetary awards to trial participants or patients, and a decline in our valuation. We currently have product liability insurance we believe is appropriate for our stage of development and may need to obtain higher levels of product liability insurance prior to marketing any therapeutic candidates. Any insurance we have or may obtain may not provide sufficient coverage against potential liabilities. Furthermore, clinical trial and product liability insurance is becoming increasingly expensive. As a result, we may be unable to obtain sufficient insurance at a reasonable cost to protect us against losses caused by product liability claims with a potentially material adverse effect on our business.

Our employees may engage in misconduct or other improper activities, including noncompliance with regulatory standards and requirements, which could have a material adverse effect on our business.

We are exposed to the risk of employee fraud or other misconduct. Misconduct by employees could include, but is not limited to:

•intentional failures to comply with FDA or U.S. health care laws and regulations, or applicable laws, regulations, guidance, or codes of conduct set by foreign governmental authorities or self-regulatory industry organizations;

•a provision of inaccurate information to any governmental authorities such as FDA;

•noncompliance with manufacturing standards we may establish;

•noncompliance with federal and state healthcare fraud and abuse laws and regulations;

•noncompliance with the U.S. Foreign Corrupt Practices Act (the FCPA) and similar anti-bribery or anti-corruption laws, regulations or rules of other countries in which we operate; and

•a failure to report financial information or data accurately or a failure to disclose unauthorized activities to us.

In particular, sales, marketing and business arrangements in the healthcare industry are subject to extensive laws, regulations, guidance and codes of conduct intended to prevent fraud, kickbacks, self-dealing and other abusive practices. These laws, regulations, guidance statements, and codes of conduct may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, customer incentive program, health care professional, and other business arrangements. As our business is heavily regulated, it involves significant interaction with government officials, including potentially officials of non-U.S. governments. Additionally, in many countries, healthcare providers are employed by the government, and the purchasers of biopharmaceuticals are government entities. As a result, our dealings with are subject to regulation and such healthcare providers and employees of such purchasers may be considered “foreign officials” as defined in the FCPA. Recently, the Securities and Exchange Commission, or SEC, and Department of Justice have increased their FCPA enforcement activities with respect to biotechnology companies. We also may be subject to U.S. and foreign export controls, trade sanctions and import laws and regulations and if we fail to comply with these laws and regulations, we may face significant penalties, finds and/or denial of certain export privileges.

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Employee misconduct could also involve the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions, including debarment or disqualification of those employees from participation in FDA regulated activities and serious harm to our reputation. This could include violations of provisions of the U.S. federal Health Insurance Portability and Accountability Act, or HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, other U.S. federal and state law, and requirements of non-U.S. jurisdictions, including the European Union General Data Protection Regulation.

It is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws, regulations, guidance or codes of conduct. Furthermore, we may be held liable under the FCPA and similar laws in other jurisdictions for the corrupt or other illegal activities of our employees, our third-party business partners, representatives and agents, even if we do not explicitly authorize such activities. If any such governmental investigations or other actions or lawsuits are instituted against us, and we are not successful in defending such actions or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant fines, exclusion from government programs, or other sanctions.

Our business involves the use of hazardous materials and we and our third-party manufacturers must comply with environmental laws and regulations, which may be expensive and restrict how we conduct business.

Our third-party manufacturers’ activities and our own activities involve the controlled storage, use and disposal of hazardous and flammable materials, including the components of our pharmaceutical product candidates, test samples and reagents, biological materials and other hazardous compounds. We and our manufacturers are subject to federal, state, local, and foreign laws and regulations governing the use, generation, manufacture, storage, handling, and disposal of these hazardous materials. Although we believe our safety procedures for handling and disposing of these materials and waste products comply with the standards prescribed by these laws and regulations, we cannot eliminate the risk of accidental injury or contamination from the use, storage, handling, or disposal of hazardous materials. In the event of an accident, state, or federal or other applicable authorities may curtail our use of these materials and/or interrupt our business operations. In addition, if an accident or environmental discharge occurs, or if we discover contamination caused by prior operations, including by prior owners and operators of properties we acquire, we could be liable for cleanup obligations, damages, and fines. If such unexpected costs are substantial, this could significantly harm our financial condition and results of operations.

Compliance with governmental regulations regarding the treatment of animals used in research could increase our operating costs, which would adversely affect the commercialization of our technology.

The Animal Welfare Act, or AWA, is the federal law covering the treatment of certain animals used in research. Currently, the AWA imposes a wide variety of specific regulations governing the humane handling, care, treatment, and transportation of certain animals by producers and users of research animals, most notably relating to personnel, facilities, sanitation, cage size and feeding, watering, and shipping conditions. Third parties with whom we contract are subject to registration, inspections, and reporting requirements under the AWA. Furthermore, some states have their own regulations, including general anti-cruelty legislation, which establish certain standards in handling animals. Comparable rules, regulations, and or obligations exist in many foreign jurisdictions. If we or our contractors fail to comply with regulations concerning the treatment of animals used in research, we may be subject to fines and penalties and adverse publicity, and our operations could be adversely affected.

Our current operations are concentrated in one location and any events affecting this location may have material adverse consequences.

Our current operations are located in facilities situated in Seattle, Washington. Any unplanned event, such as flood, fire, explosion, earthquake, extreme weather condition, medical epidemics, power shortage, power outage, telecommunication failure, or other natural or man-made accidents or incidents resulting in our company being unable to fully utilize the facilities, may have a material adverse effect on our ability to operate our business, particularly on a daily basis, and have significant negative consequences on our financial and operating conditions. Loss of access to these facilities may result in increased costs, delays in the development of our therapeutic candidates, or interruption of our business operations. As part of our risk management policy, we maintain insurance coverage at levels we believe are appropriate for our business. However, in the event of an accident or incident at these facilities, we cannot assure you the amounts of insurance will be sufficient to satisfy any damages and losses or that the insurance covers all risks. If our facilities are unable to operate because of an accident or incident or for any other reason, even for a short period of time, any or all of our research and development programs may be harmed. Any business interruption may have a material adverse effect on our business, financial position, results of operations, and prospects.

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Our business may be affected by litigation and government investigations.

We may from time to time receive inquiries and subpoenas and other types of information requests from government authorities and others and we may become subject to claims and other actions related to our business activities. While the ultimate outcome of investigations, inquiries, information requests, and legal proceedings is difficult to predict, defense of litigation claims can be expensive, time-consuming and distracting, and adverse resolutions or settlements of those matters may result in, among other things, modification of our business practices, costs, and significant payments, any of which could have a material adverse effect on our business, financial condition, results of operations, and prospects.

Risks Related to Our Financial Position and Capital Needs

The investment of our cash and cash equivalents in fixed income and other marketable securities is subject to risks which may cause losses and affect the liquidity of these investments.

As of September 30, 2022, we had $277.1 million in cash and cash equivalents, restricted cash, and investments. We expect to continue to invest our excess cash in fixed income and other marketable securities. These investments are subject to general credit, liquidity, market and interest rate risks. We may realize losses in the fair value of these investments, an inability to access cash in these investments for a potentially meaningful period, or a complete loss of these investments, which would have a negative effect on our financial statements.

Our business may be materially affected by changes to fiscal and tax policies. Negative or unexpected tax consequences could adversely affect our results of operations.

New tax laws, statutes, rules, regulations or ordinances could be enacted at any time, which could adversely affect our business operations, and our business and financial performance. Further, existing tax laws, statutes, rules, regulations or ordinances could be interpreted, changed, modified or applied adversely to us. For example, the Tax Cuts and Jobs Act of 2017, or TCJA, enacted in December 2017, as modified by the Coronavirus Aid, Relief, and Economic Security Act, or the CARES Act, enacted in April 2020, significantly changed the U.S. Internal Revenue Code, or the Code. Such changes include a reduction in the corporate tax rate and limitations on certain corporate deductions and credits, among other changes. We have generally accounted for changes related to the TCJA in accordance with our understanding of the legislation and guidance available as of the date of this filing as described in more detail in our financial statements and will continue to monitor and assess the impact of the federal legislation on our business and the extent to which various states conform to federal tax law. As another example, on August 16, 2022, the Inflation Reduction Act of 2022, or IRA, was signed into law, with tax provisions primarily focused on implementing a 15% minimum tax on global adjusted financial statement income, effective for tax years beginning after December 31, 2022, and a 1% excise tax on share repurchases occurring after December 31, 2022. Given its recent pronouncement, it is unclear at this time what, if any, impact the IRA will have on our company's tax rate and financial results. We will continue to evaluate the IRA’s impact (if any) as further information becomes available. In addition, adverse changes in the financial outlook of our operations or further changes in tax laws or regulations could lead to changes in our valuation allowances against deferred tax assets on our accompanying Condensed Consolidated Balance Sheets, which could materially affect our results of operations.

Our pre-merger net operating loss carryforwards and certain other tax attributes may be subject to limitations.

In general, under Section 382 and 383 of the Code, a corporation that undergoes an “ownership change” is subject to limitations on its ability to utilize its pre-change net operating loss carryforwards, or NOL carryforwards, to offset future taxable income. In general, an ownership change occurs if the aggregate stock ownership of certain stockholders, generally stockholders beneficially owning five percent or more of a corporation’s common stock, applying certain look-through and aggregation rules, increases by more than 50 percentage points (by value) over such stockholders’ lowest percentage ownership during the testing period, generally three years. It is possible that our NOL carryforwards and certain other tax attributes may be subject to limitation as a result of ownership changes in the past or in the future because of, among other things, shifts in our stock ownership, many of which are outside our control. Consequently, even if we achieve profitability, we may not be able to utilize a material portion of our NOL carryforwards and certain other tax attributes, which could have a material adverse effect on cash flow and results of operations.

 Provisions of our debt instruments may restrict our ability to pursue our business strategies.

Our term loan agreement requires us, and any debt financing we may obtain in the future may require us, to comply with various covenants that limit our ability to, among other things: 

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•dispose of assets;

•complete mergers or acquisitions;

•incur indebtedness;

•encumber assets;

•pay dividends or make other distributions to holders of our capital stock;

•make specified investments;

•engage in any new line or business; and

•engagement in certain transactions with our affiliates.

These restrictions could inhibit our ability to pursue our business strategies. If we default under our term loan agreement, including a material adverse change in our business, operations or condition (financial or otherwise), and such event of default is not cured or waived, the lenders could terminate commitments to lend and cause all amounts outstanding with respect to the debt to be due and payable immediately, which in turn could result in cross defaults under other debt instruments. Our assets and cash flow may not be sufficient to fully repay borrowings under our outstanding debt instruments if some or all of these instruments are accelerated upon a default. We may incur additional indebtedness in the future. The debt instruments governing such indebtedness could contain provisions that are as, or more, restrictive than our existing debt instruments. If we are unable to repay, refinance or restructure our indebtedness when payment is due, the lenders could proceed against the collateral granted to them to secure such indebtedness or force us into bankruptcy or liquidation.

Risks Related to COVID-19 and Other Health Epidemics

The COVID-19 coronavirus could adversely impact our business, including our clinical trials.

In December 2019, a novel strain of coronavirus, SARS-CoV-2, the causative agent of coronavirus disease 2019, or COVID-19, was first reported. Since then, SARS-CoV-2 has spread globally, including countries in which we have planned or active clinical trial sites. We have experienced and may continue to experience disruptions that could severely impact our business and clinical trials, including:

•delays or difficulties in enrolling patients in our clinical trials;

•delays or difficulties in clinical site initiation, including difficulties in recruiting clinical site investigators and clinical site staff;

•diversion of healthcare resources away from the conduct of clinical trials, including the diversion of hospitals serving as our clinical trial sites and hospital staff supporting the conduct of our clinical trials;

•interruption of key clinical trial activities, such as clinical trial site monitoring, due to limitations on travel imposed or recommended by federal or state governments, employers and others;

•limitations in employee resources that would otherwise be focused on the conduct of our clinical trials, including because of sickness of employees or their families or the desire of employees to avoid contact with large groups of people;

•delays in receiving approval from local regulatory authorities and ethics committees to initiate our planned clinical trials;

•delays in clinical sites receiving the supplies and materials needed to conduct our clinical trials;

•interruption in global shipping that may affect the transport of clinical trial materials, such as investigational drug product used in our clinical trials;

•changes in local regulations as part of a response to the COVID-19 coronavirus outbreak which may require us to change the ways in which our clinical trials are conducted, which may result in unexpected costs, or to discontinue the clinical trials altogether;

•delays in necessary interactions with local regulators, ethics committees and other important agencies and contractors due to limitations in employee resources or forced furlough of government employees; and

•refusal of the FDA to accept data from clinical trials whose conduct has been affected by the COVID-19 outbreak, such as due to missing data.

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Further, we may be required to develop and implement additional clinical trial policies and procedures designed to help protect subjects from the COVID-19 virus. For example, in March 2020, the FDA issued a guidance, which the FDA subsequently updated, on conducting clinical trials during the pandemic, which describes a number of considerations for sponsors of clinical trials impacted by the pandemic. The FDA has also published other COVID-19-related industry guidance, including updates to previous guidance documents, regarding Good Manufacturing Practices, remote interactive evaluations of drug manufacturing and bioresearch monitoring facilities, and drug product manufacturing and supply chain inspections, among others. It is possible that additional governmental action will be taken to address the COVID-19 pandemic. The ultimate impact of the COVID-19 pandemic on our business operations is highly uncertain and subject to change and will depend on future developments, including new regulatory requirements and changes to existing regulations.

The global outbreak of the COVID-19 coronavirus continues to evolve. The extent to which the COVID-19 coronavirus may impact our business and clinical trials will depend on future developments, which are highly uncertain and cannot be predicted with confidence, such as the duration of the outbreak, travel restrictions and social distancing in the United States and other countries, business closures or business disruptions and the effectiveness of actions taken in the United States and other countries to contain and treat the disease. For example, with the increased availability of vaccines in North America and certain countries around the world, the rate of additional COVID-19 infections and hospitalizations declined in certain locations for periods of time, resulting in relaxed restrictions and a general reopening of the economy and travel across many jurisdictions, however some jurisdictions continue to maintain or reimpose restrictions in view of increased hospitalization rates and cases due to COVID-19 variants. While certain of these developments are positive, reduced vaccine availability, resistance to vaccination by certain persons or ineffectiveness of vaccines against certain variants may result in increasing infection and hospitalization rates, which could be further complicated by the emergence of more virulent or infectious variants of the virus.

We face risks related to health epidemics and other outbreaks, which could significantly disrupt our operations and/or business.

Our business could be adversely impacted by the effects of the COVID-19 outbreak originating in China, or by other epidemics. Our supply chain for raw materials, drug substance or drug product is worldwide, including China, and accordingly could be subject to disruption. There may be restrictions on the export or shipment of raw materials, drug substance or drug product that could materially delay our business or clinical trials.

Certain of our research and development efforts are also conducted globally, for example the ALPN-303 healthy volunteer study includes investigative sites in Australia and our Synergy trial includes investigative sites in Korea and Poland. A health epidemic or other outbreak, including the current COVID-19 outbreak, may materially and adversely affect our business, financial condition and results of operations. The extent to which the outbreak impacts our results will depend on future developments, which are highly uncertain and cannot be predicted, including new information which may emerge concerning the severity of the outbreak and the actions to contain the outbreak or treat its impact, among others.

Risks Related to Cybersecurity

Our computer systems, or those of any of our CROs, manufacturers, other contractors or consultants or potential future collaborators, may fail or suffer security or data privacy breaches or incidents or other unauthorized or improper access to, use of, or destruction of our proprietary or confidential data, employee data, or personal data, which could result in additional costs, loss of revenue, significant liabilities, harm to our brand and material disruption of our operations.

Despite the implementation of security measures in an effort to protect systems that store our information, given their size and complexity and the increasing amounts of information maintained on our internal information technology systems, and those of our third-party CROs, other contractors (including sites performing clinical trials) and consultants, these systems are potentially vulnerable to breakdown or other damage or interruption from service interruptions, system malfunction, natural disasters, terrorism, war and telecommunication and electrical failures, as well as security breaches and incidents from inadvertent or intentional actions by our employees, contractors, consultants, business partners, and/or other third parties, or from cyber-attacks by malicious third parties (including supply chain cyber-attacks or the deployment of harmful malware, ransomware, denial-of-service attacks, social engineering and other means to affect service reliability and threaten the confidentiality, integrity and availability of information), which may compromise our system infrastructure or lead to the loss, destruction, alteration, prevention of access to, disclosure, or dissemination of, or damage or unauthorized access to, our data (including trade secrets or other confidential information, intellectual property, proprietary business information, and personal information) or data that is processed or maintained on our behalf, or other assets, which could result in financial, legal, business and reputational harm to us. Companies have experienced an increase in phishing and social engineering attacks from third parties in connection with the COVID-19 pandemic, and the increase in remote working further increases security threats. Additionally, cybersecurity researchers have warned of heightened risks of cyberattacks in connection with Russia’s activities

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in Ukraine. To the extent that any disruption or security incident were to result in any loss, destruction, unavailability, alteration, disclosure, or dissemination of, or damage or unauthorized access to, our applications, any other data processed or maintained on our behalf or other assets, or for it to be believed or reported that any of these occurred, we could incur liability, financial harm and reputational damage and the development and commercialization of our product candidates could be delayed. We cannot assure you that our data protection efforts and our investment in information technology, or the efforts or investments of CROs, consultants or other third parties, will prevent significant breakdowns or breaches in systems or other cyber incidents that cause loss, destruction, unavailability, alteration or dissemination of, or damage or unauthorized access to, our data and other data processed or maintained on our behalf or other assets that could have a material adverse effect upon our reputation, business, operations or financial condition. We and certain of our contractors and consultants are, from time to time, subject to cyberattacks and security incidents. While we do not believe that we have experienced any significant system failure, accident or security breach to date, if any system failure, accident, or other disruption, or any security breach or incident, impacting us or any of our third-party CROs or other contractors or consultants, were to occur and cause interruptions in our operations, it could result in a material disruption of our programs and the development of our product candidates could be delayed. In addition, the loss of clinical trial data for our product candidates could result in delays in our marketing approval efforts and significantly increase our costs to recover or reproduce the data. Further, any such event that leads to loss, damage, or unauthorized access to, or use, alteration, or disclosure, dissemination or other processing of, personal information, including personal information regarding our clinical trial subjects or employees, could harm our reputation directly, compel us to comply with federal and/or state breach notification laws and foreign law equivalents, subject us to mandatory corrective action, and otherwise subject us to liability under laws and regulations that protect the privacy and security of personal information, which could result in significant legal and financial exposure and reputational damages that could potentially have an adverse effect on our business.

Notifications and follow-up actions related to a security breach or incident could impact our reputation and cause us to incur significant costs, including legal expenses and remediation costs. For example, the loss of clinical trial data from completed or future clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the lost data. We expect to incur significant costs in an effort to detect and prevent security breaches and incidents, and we may face increased costs and requirements to expend substantial resources in the event of an actual or perceived security breach or incident. We also rely on third parties to manufacture our product candidates, and similar events relating to their computer systems could also have a material adverse effect on our business. To the extent that any disruption or security incident were to result in any loss, destruction, or alteration of, unavailability of, or damage or unauthorized access to, our data or other information that is processed or maintained on our behalf, or inappropriate disclosure of or dissemination of any such information, or if any of these were perceived or reported to have occurred, we could be exposed to litigation and governmental investigations, the further development and commercialization of our product candidates could be delayed, and we could be subject to significant fines or penalties for any noncompliance with certain state, federal and/or international privacy and security laws.

Our insurance policies may not be adequate to compensate us for the potential losses arising from any such disruption in or, failure or security breach or incident of or impacting our systems or third-party systems where information important to our business operations or commercial development is stored. In addition, such insurance may not be available to us in the future on economically reasonable terms, or at all. Further, our insurance may not cover all claims made against us and could have high deductibles in any event, and defending a suit, regardless of its merit, could be costly and divert management attention.

Our information technology systems could face serious disruptions adversely affecting our business.

Our information technology and other internal infrastructure systems, including corporate firewalls, servers, leased lines, and connection to the Internet, face the risk of systemic failure potentially disruptive to our operations. A significant disruption in the availability of our information technology and other internal infrastructure systems, or those of third parties that perform services or supply materials to us, could cause interruptions in our collaborations with our partners and delays in our research and development work.

Our facility is located in Seattle, Washington. We have not undertaken a systematic analysis of the potential consequences to our business and financial results from a major flood, blizzard, fire, earthquake, power loss, terrorist activity, pandemics or other disasters and do not have a recovery plan for such disasters. Also, our contract development and manufacturing organizations’ and suppliers’ facilities are located in multiple locations where other natural disasters or similar events which could severely disrupt our operations, could expose us to liability and could have a material adverse effect on our business. The occurrence of any of these business disruptions could seriously harm our operations and financial condition and increase our costs and expenses.

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Risks Related to Our Intellectual Property

If we are not able to obtain and enforce patent protection for our technology, including therapeutic candidates, therapeutic products, and platform technology, development of our therapeutic candidates and platform, and commercialization of our therapeutic products may be materially and adversely affected.

Our success depends in part on our ability to obtain and maintain patents and other forms of intellectual property rights, including in-licenses of intellectual property rights of others, for our technology, including platform technology and therapeutic candidates and products, methods used to manufacture our therapeutic candidates and products, and methods for treating patients using our therapeutic candidates and products, as well as our ability to preserve our trade secrets, to prevent third parties from infringing upon our proprietary rights, and to operate without infringing upon the proprietary rights of others. Our scientific platform and substantially all of our intellectual property have been developed internally. As of September 30, 2022, our patent portfolio consists of 53 granted patents and over 170 pending patent applications. We may not be able to apply for patents on certain aspects of our technology, including therapeutic candidates and products, in a timely fashion or at all. Any future patents we obtain may not be sufficiently broad to prevent others from using our technology or from developing competing therapeutics and technology. There is no guarantee that any of our pending patent applications will result in issued or granted patents, any of our issued or granted patents will not later be found to be invalid or unenforceable, or any issued or granted patents will include claims sufficiently broad to cover our technology, including platform technology and therapeutic candidates and products, or to provide meaningful protection from our competitors. Moreover, the patent position of pharmaceutical and biotechnology companies can be highly uncertain because it involves complex legal and factual questions. We will be able to protect our proprietary rights from unauthorized use by third parties only to the extent our current and future technology, including platform technology and therapeutic candidates and products, are covered by valid and enforceable patents or are effectively maintained as trade secrets. If third parties disclose or misappropriate our proprietary rights, it may materially and adversely impact our competitive position in the market.

The U.S. Patent and Trademark Office, or USPTO, and various foreign governmental patent agencies require compliance with a number of procedural, documentary, fee payment, and other provisions during the patent process. There are situations in which noncompliance can result in abandonment or lapse of a patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. Patent offices may be affected by COVID-19 or other health epidemic shut-downs, resulting in, for example, non-essential administrative tasks being delayed or eliminated. This could affect patent rights, including the partial or complete loss of patent rights in jurisdictions such as the USPTO and international patent offices. In such an event, competitors might be able to enter the market earlier than would otherwise have been the case. Further, the standards applied by the USPTO and foreign patent offices in granting patents are not always applied uniformly or predictably. For example, there is no uniform worldwide policy regarding patentable subject matter or the scope of claims allowable in biotechnology and pharmaceutical patents. As such, we do not know the degree of future protection we will have on our technology, including platform technology and therapeutic candidates and products. While we will endeavor to try to protect our technology, including platform technology and therapeutic candidates and products, with intellectual property rights such as patents, as appropriate, the process of obtaining patents is time-consuming, expensive, and sometimes unpredictable, and we can provide no assurances our technology, including our platform technology, therapeutic candidates and products, will be adequately protected in the future against unauthorized uses or competing claims by third parties.

In addition, recent and future changes to the patent laws and to the rules of the USPTO and foreign patent offices may have a significant impact on our ability to protect our technology, including therapeutic candidates and products, and enforce our intellectual property rights. For example, the Leahy-Smith America Invents Act enacted in 2011 involves significant changes in patent legislation. In addition, we cannot assure that court rulings or interpretations of any court decision will not adversely impact our patents or patent applications. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, there also may be uncertainty with respect to the value of patents, once obtained. Depending on decisions by the U.S. Congress, the federal courts, the USPTO, or made in foreign jurisdictions, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents we might obtain in the future.

Moreover, no earlier than October 1, 2022, European applications will soon have the option, upon grant of a patent, of becoming a Unitary Patent which will be subject to the jurisdiction of the Unitary Patent Court, or UPC. This will be a significant change in European patent practice. As the UPC is a new court system, there is no precedent for the court, increasing the uncertainty of any patent litigation in Europe.

The issuance of a patent is not conclusive as to its inventorship, scope, validity, or enforceability. Once granted, patents may remain open to opposition, interference, re-examination, post-grant review, inter partes review, revocation, nullification, or derivation action in court or before patent offices or similar proceedings before or after allowance or grant, during which time third parties can raise objections against such initial grant. In the course of such proceedings, which may

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continue for a protracted period of time, the patent owner may be compelled to limit the scope of the pending, allowed or granted claims thus attacked or may lose the allowed or granted claims altogether. Our patent risks include that:

•others may, or may be able to, make, use, offer to sell, or sell compounds that are the same as or similar to our therapeutic candidates and products but that are not covered by the claims of the patents we own or license;

•we or our licensors, collaborators, or any future collaborators may not be the first to file patent applications covering certain aspects of our technology, including our platform technology, therapeutic candidates and products;

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

•a third party may challenge our patents and, if challenged, a court may not hold that our patents are valid, enforceable, or that a third party is infringing;

•a third party may challenge our patents in various patent offices and, if challenged, we may be compelled to limit the scope of our pending, allowed or granted claims or lose the allowed or granted claims altogether;

•any issued patents we own or have licensed may not provide us with any competitive advantages, or may be challenged by third parties;

•we may not develop additional proprietary technologies that are patentable;

•the patents of others could harm our business; and

•our competitors could conduct research and development activities in countries where we do not or will not have enforceable patent rights and then use the information learned from such activities to develop competitive products for sale in major commercial markets where we do not or will not have enforceable patent rights.

We may license patent rights from third-party owners or licensors. If such owners or licensors do not properly or successfully obtain, maintain or enforce the patents underlying such licenses, or if they retain or license to others any competing rights, our competitive position and business prospects may be materially and adversely affected.

We may rely upon intellectual property rights licensed from third parties to protect our technology, including platform technology and therapeutic candidates and products. To date, we have in-licensed some intellectual property, including on a non-exclusive basis intellectual property relating to commercially-available cell lines involved in the manufacture of our vIgD programs; however, we may also license additional third-party intellectual property in the future, to protect our technology, including intellectual property relating to our platform technology and therapeutic candidates and products. Our success will depend in part on the ability of our licensors to obtain, maintain, and enforce patent protection for our licensed intellectual property, in particular those patents to which we have secured exclusive rights. Our licensors may elect not to prosecute, or may be unsuccessful in prosecuting, any patent applications licensed to us. Even if patents issue or are granted, our licensors may fail to maintain these patents, may determine not to pursue litigation against other companies infringing these patents, or may pursue litigation less aggressively than we would. Further, any additional licenses we enter into may be non-exclusive and we may not be able to obtain exclusive rights, which would potentially allow third parties to develop competing products or technology. Without protection for, or exclusive right to, any intellectual property we may license, other companies might be able to offer substantially identical or similar product(s) for sale, which could adversely affect our competitive business position and harm our business prospects. In addition, we may need to sublicense any rights we have under third-party licenses to current or future collaborators or any future strategic partners. Any impairment of these sublicensed rights could result in reduced revenue under or result in termination of an agreement by one or more of our collaborators or any future strategic partners.

Patent terms may be inadequate to protect our competitive position on our platform technology and therapeutic candidates and products for an adequate amount of time.

Patents have a limited lifespan. In the United States and abroad, if all maintenance fees/annuity fees are timely paid, the natural expiration of a patent is generally 20 years from its earliest non-provisional filing date. The protection a patent affords is limited. Even if patents covering our products are obtained, once the patent life has expired, we may be open to competition from competitive products. Given the amount of time required for the development, testing and regulatory review of new products, patents protecting such products might expire before or shortly after such products are approved and commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to ours.

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We may be unable to protect our patent intellectual property rights throughout the world.

Obtaining a valid and enforceable issued or granted patent covering our technology, including therapeutic candidates and products, in the United States and worldwide can be extremely costly. In jurisdictions where we have not obtained patent protection, competitors may use our technology, including our platform technology and therapeutic candidates and products, to develop their own products, and further, may commercialize such products in those jurisdictions and export otherwise infringing products to territories where we have not obtained patent protection. In certain instances, a competitor may be able to export otherwise infringing products in territories where we will obtain patent protection. In jurisdictions outside the United States where we will obtain patent protection, it may be more difficult to enforce a patent as compared to the United States. Competitor products may compete with our future products in jurisdictions where we do not or will not have issued or granted patents or where our issued or granted patent claims or other intellectual property rights are not sufficient to prevent competitor activities in these jurisdictions. The legal systems of certain countries, particularly certain developing countries, make it difficult to enforce patents and such countries may not recognize other types of intellectual property protection, particularly relating to biopharmaceuticals. Geo-political actions in the United States and in foreign countries could increase the uncertainties and costs surrounding the prosecution or maintenance of our patent applications or those of any current or future licensors and the maintenance, enforcement or defense of our issued patents or those of any current or future licensors. This could make it difficult for us to prevent the infringement of our patents or marketing of competing products in violation of our proprietary rights generally in certain jurisdictions. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial cost and divert our efforts and attention from other aspects of our business.

We generally file a provisional patent application first (a priority filing) at the USPTO. An international application under the Patent Cooperation Treaty, or PCT, is usually filed within twelve months after the priority filing, at times with a United States filing. Based on the PCT filing, national and regional patent applications may be filed in various international jurisdictions, such as in Europe, Japan, Australia, Canada, and the United States. We have so far not filed for patent protection in all national and regional jurisdictions where such protection may be available. In addition, we may decide to abandon national and regional patent applications before they are granted. Finally, the grant proceeding of each national or regional patent is an independent proceeding which may lead to situations in which applications might in some jurisdictions be refused by the relevant registration authorities, while granted by others. It is also quite common that, depending on the country, various scopes of patent protection may be granted on the same therapeutic candidate, product, or technology. The laws of some jurisdictions do not protect intellectual property rights to the same extent as the laws in the United States, and many companies have encountered significant difficulties in protecting and defending such rights in such jurisdictions. If we or our licensors encounter difficulties in protecting, or are otherwise precluded from effectively protecting, the intellectual property rights important for our business in such jurisdictions, the value of these rights may be diminished, and we may face additional competition from others in those jurisdictions. Many countries have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. In addition, many countries limit the enforceability of patents against government agencies or government contractors. In these countries, the patent owner may have limited remedies, which could materially diminish the value of such patent. If we or any of our licensors are forced to grant a license to third parties with respect to any patents relevant to our business, our competitive position in the relevant jurisdiction may be impaired and our business and results of operations may be adversely affected.

We or our licensors, collaborators, or any future strategic partners may become subject to third-party claims or litigation alleging infringement of patents or other proprietary rights or seeking to invalidate patents or other proprietary rights, and we may need to resort to litigation to protect or enforce our patents or other proprietary rights, all of which could be costly, time consuming, delay or prevent the development of our therapeutic candidates and commercialization of our therapeutic products, or put our patents and other proprietary rights at risk.

We or our licensors, licensees, collaborators, or any future strategic partners may be subject to third-party claims for infringement or misappropriation of patent or other proprietary rights. We are generally obligated under our license or collaboration agreements to indemnify and hold harmless our licensors, licensees, or collaborators for damages arising from intellectual property infringement by us. If we or our licensors, licensees, collaborators, or any future strategic partners are found to infringe a third-party patent or other intellectual property rights, we could be required to pay damages, potentially including treble damages, if we are found to have willfully infringed. In addition, we or our licensors, licensees, collaborators, or any future strategic partners may choose to seek, or be required to seek, a license from a third party, which may not be available on acceptable terms, if at all. Even if a license can be obtained on acceptable terms, the rights may be non-exclusive, which could give our competitors access to the same technology or intellectual property rights licensed to or from us. If we fail to obtain a required license, we or our licensee or collaborator, or any future licensee or collaborator, may be unable to effectively market therapeutic products based on our technology, which could limit our ability to generate revenue or achieve profitability and possibly prevent us from generating revenue sufficient to sustain our operations. In addition, we may find it necessary to pursue claims or initiate lawsuits to protect or enforce our patent or other intellectual property rights. The cost to us in defending or initiating any litigation or other proceeding relating to patent or other proprietary rights, even if resolved in our

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favor, could be substantial, and litigation would divert our management’s attention. Some of our competitors may be able to sustain the costs of complex patent litigation more effectively than we can because they have substantially greater resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could delay our research and development efforts and limit our ability to continue our operations.

Although we do not believe our technology infringes the intellectual property rights of others, we are aware of one or more patents or patent applications that may relate to our technology, and third parties may assert against our products alleging infringement of their intellectual property rights regardless of whether their claims have merit. Infringement claims could harm our reputation, may result in the expenditure of significant resources to defend and resolve such claims, and could require us to pay monetary damages if we are found to have infringed the intellectual property rights of others.

If we were to initiate legal proceedings against a third party to enforce a patent covering our technology, including therapeutic candidates and products, the defendant could counterclaim that our patent is invalid or unenforceable. In patent litigation in the United States, defendant counterclaims alleging invalidity or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, for example, patent ineligibility, lack of novelty, lack of written description, obviousness, or non-enablement. Grounds for an unenforceability assertion could be an allegation someone connected with prosecution of the patent withheld relevant information from the USPTO, or made a misleading statement, during prosecution. The outcome following legal assertions of invalidity and unenforceability during patent litigation is unpredictable. With respect to the validity question, for example, we cannot be certain there is no invalidating prior art, of which we and the patent examiner were unaware during prosecution. If a defendant were to prevail on a legal assertion of invalidity or unenforceability, we would lose at least part, and perhaps all, of the patent protection on our technology, including our platform technology and therapeutic candidates and products. Such a loss of patent protection could have a material adverse impact on our business. Patents and other intellectual property rights also will not protect our technology, including our platform technology and therapeutic candidates and products, if competitors design around our protected technology, including our platform technology and therapeutic candidates and products, without legally infringing our patents or other intellectual property rights.

It is also possible we have failed to identify relevant third-party patents or applications. For example, patent applications in the United States and elsewhere are published approximately 18 months after the earliest filing for which priority is claimed, with such earliest filing date being commonly referred to as the priority date. Therefore, patent applications covering our technology, including our platform technology and therapeutic candidates and products, could have been filed by others without our knowledge. Additionally, pending patent applications which have been published can, subject to certain limitations, be later amended in a manner that could cover our technology, including our platform technology and therapeutic candidates and products. Third-party intellectual property rights holders may also actively bring infringement claims against us. We cannot guarantee we will be able to successfully settle or otherwise resolve such infringement claims. If we are unable to successfully settle future claims on terms acceptable to us, we may be required to engage in or continue costly, unpredictable, and time-consuming litigation and may be prevented from, or experience substantial delays in, marketing our technology, including therapeutic candidates and products. If we fail in any such dispute, in addition to being forced to pay damages, we may be temporarily or permanently prohibited from commercializing our technology, including a therapeutic product, held to be infringing. We might, if possible, also be forced to redesign therapeutic candidates or products so we no longer infringe the third-party intellectual property rights. Any of these events, even if we were ultimately to prevail, could require us to divert substantial financial and management resources we would otherwise be able to devote to our business.

If we fail to comply with our obligations under any license, collaboration, or other agreements, we may be required to pay damages and could lose intellectual property rights necessary for developing and protecting our technology, including our platform technology, therapeutic candidates, and therapeutic products, or we could lose certain rights to grant sublicenses, either of which could have a material adverse effect on our results of operations and business prospects.

Our current licenses impose, and any future licenses we enter into are likely to impose, various development, commercialization, funding, milestone, royalty, diligence, sublicensing, insurance, patent prosecution and enforcement, and other obligations on us. If we breach any of these obligations, or use the intellectual property licensed to us in an unauthorized manner, we may be required to pay damages and the licensor may have the right to terminate the license, which could result in us being unable to develop, manufacture, and sell or offer to sell products covered by the licensed technology or enable a competitor to gain access to the licensed technology. Moreover, our licensors may own or control intellectual property that has not been licensed to us and, as a result, we may be subject to claims, regardless of their merit, that we are infringing or otherwise violating the licensor’s rights. In addition, while we cannot currently determine the amount of the royalty obligations we would be required to pay on future sales of licensed products, if any, the amounts may be significant. The amount of our future royalty obligations will depend on the technology and intellectual property we use in therapeutic products we successfully develop and commercialize, if any. Therefore, even if we successfully develop and commercialize therapeutic products, we may be unable to achieve or maintain profitability.

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If we do not obtain patent term extension and data exclusivity for any therapeutic candidate or product we may develop, our business may be materially harmed.

Depending upon the timing, duration, and specifics of any FDA marketing approval of any therapeutic candidate or product we may develop, one or more of our or in-licensed U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984 (Hatch-Waxman Act). The Hatch-Waxman Act permits a patent term extension of up to five years as compensation for patent term lost during the FDA regulatory review process. A patent term extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, only one patent may be extended and only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended. Similar extensions as compensation for patent term lost during regulatory review processes are also available in certain foreign countries and territories, such as in Europe under a Supplementary Patent Certificate. However, we may not be granted an extension in the United States and/or foreign countries and territories because of, for example, failing to exercise due diligence during the testing phase or regulatory review process, failing to apply within applicable deadlines, failing to apply prior to expiration of relevant patents, or otherwise failing to satisfy applicable requirements. Moreover, the applicable time period or the scope of patent protection afforded could be less than we request. If we are unable to obtain patent term extension or the term of any such extension is shorter than what we request, our competitors may obtain approval of competing products following our patent expiration, and our business, financial condition, results of operations, and growth prospects could be materially harmed.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patent protection for certain aspects of our technology, including platform technology and therapeutic candidates and products, we also consider trade secrets, including confidential and unpatented know-how, important to the maintenance of our competitive position. We protect trade secrets and confidential and unpatented know-how, in part, by entering into non-disclosure and confidentiality agreements with parties who have access to such knowledge, such as our employees, corporate collaborators, outside scientific collaborators, CROs, contract manufacturers, consultants, advisors, and other third parties. We also enter into confidentiality and invention or patent assignment agreements with our employees and consultants obligating them to maintain confidentiality and assign their inventions to us. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. We also cannot guarantee that we have entered into such agreements with each party that may have or has had access to our trade secrets or proprietary technology and processes. Enforcing a claim in the event of a party illegally disclosing or misappropriating a trade secret is difficult, expensive, and time-consuming, and the outcome is unpredictable. In addition, some courts in the United States and certain foreign jurisdictions are less willing or unwilling to protect trade secrets. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor, our competitive position would be harmed.

We are also subject both in the United States and outside the United States to various regulatory schemes regarding requests for the information we provide to regulatory authorities, which may include, in whole or in part, trade secrets or confidential commercial information. While we are likely to be notified in advance of any disclosure of such information and would likely object to such disclosure, there can be no assurance our challenge to the request would be successful.

We may be in the future subject to claims we or our employees or consultants have wrongfully used or disclosed alleged trade secrets of our employees’ or consultants’ former employers or their clients. These claims may be costly to defend and if we do not successfully do so, we may be required to pay monetary damages, may be prohibited from using some of our research and development and may lose valuable intellectual property rights or personnel.

Many of our employees were previously employed at universities or biotechnology or pharmaceutical companies, including our current and potential competitors. We may receive correspondence from other companies alleging the improper use or disclosure, and have received, and may in the future receive, correspondence from other companies regarding the use or disclosure, by certain of our employees who have previously been employed elsewhere in our industry, including with our competitors, of their former employer’s trade secrets or other proprietary information. Responding to these allegations can be costly and disruptive to our business, even when the allegations are without merit, and can be a distraction to management. We may be subject to claims in the future that our employees have, or we have, inadvertently or otherwise used or disclosed trade secrets or other proprietary information of their former employers. Litigation may be necessary to defend against these claims. If we fail in defending current or future claims, in addition to paying monetary damages, we may lose valuable intellectual property rights, personnel, or the ability to use some of our research and development. A loss of intellectual property, key research personnel, or their work product could hamper our ability to commercialize, or prevent us from commercializing, our therapeutic candidates, which could severely harm our business. Even if we are successful in defending against these claims, litigation could result in substantial costs and be a distraction to management.

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

Our trademarks or trade names may be challenged, infringed, circumvented, or declared generic or determined to be infringing on other marks. Any trademark litigation could be expensive. We may not be able to protect our rights to these trademarks and trade names or may be forced to stop using these names, which we need for name recognition by potential partners or customers in our markets of interest. If we are unable to establish name recognition based on our trademarks and trade names, we may not be able to compete effectively, and our business may be materially and adversely affected.

Third parties may independently develop similar or superior technology.

There can be no assurance others will not independently develop, or have not already developed, similar or more advanced technologies than our technology or that others will not design around, or have not already designed around, aspects of our technology or our trade secrets developed therefrom. If third parties develop technology similar or superior to our technology, or they successfully design around our current or future technology, our competitive position, business prospects, and results of operations could be materially and adversely affected.

Breaches of our internal computer systems, or those of our contractors, vendors, or consultants, may place our patents or proprietary rights at risk.

The loss of clinical or preclinical data or data from any future clinical trial involving our technology, including therapeutic candidates and products, could result in delays in our development and regulatory filing efforts and significantly increase our costs. In addition, theft or other exposure of data may interfere with our ability to protect our intellectual property, including trade secrets, and other information critical to our operations. We have experienced in the past, and may experience in the future, unauthorized intrusions into our internal computer systems, including portions of our internal computer systems storing information related to our platform technology, therapeutic candidates and products, and we can provide no assurances that certain sensitive and proprietary information relating to one or more of our therapeutic candidates or products has not been, or will not in the future be, compromised. Although we have invested significant resources to enhance the security of our computer systems, there can be no assurances we will not experience additional unauthorized intrusions into our computer systems, or those of our CROs, vendors, contractors, and consultants, that we will successfully detect future unauthorized intrusions in a timely manner, or that future unauthorized intrusions will not result in material adverse effects on our financial condition, reputation, or business prospects. Payments related to the elimination of ransomware may materially affect our financial condition and results of operations.

Certain data breaches must also be reported to affected individuals and the government under applicable data protection laws, and financial penalties may also apply.

Risks Related to Government Regulation

We may be unable to obtain U.S. or foreign regulatory approval and, as a result, may be unable to commercialize our therapeutic candidates.

Our therapeutic candidates are subject to extensive governmental regulations relating to, among other things, research, development, testing, manufacture, quality control, approval, labeling, packaging, promotion, storage, record-keeping, advertising, distribution, sampling, pricing, sales and marketing, safety, post-approval monitoring and reporting, and export and import of drugs. Rigorous preclinical testing and clinical trials and an extensive regulatory approval process are required to be completed successfully in the United States and in many foreign jurisdictions before a new therapeutic can be marketed. Satisfaction of these and other regulatory requirements is costly, time consuming, uncertain, and subject to unanticipated delays. We have not obtained regulatory approval for any therapeutic candidates, and it is possible none of the therapeutic candidates we may develop will obtain the regulatory approvals necessary for us or our collaborators to begin selling them.

We have very limited experience in conducting and managing the clinical trials necessary to obtain regulatory approvals, including approval by the FDA as well as foreign regulatory authorities, such as the EMA. The time required to obtain FDA and foreign regulatory approvals is unpredictable but typically takes many years following the commencement of clinical trials, depending upon the type, complexity, and novelty of the therapeutic candidate, and at the substantial discretion of the regulatory authorities. The standards the FDA and its foreign counterparts use when regulating us are not always applied predictably or uniformly and can change. Any analysis we perform of data from preclinical and clinical activities is subject to confirmation and interpretation by regulatory authorities, who could delay, limit, or prevent regulatory approval. We may also encounter unexpected delays or increased costs due to new government regulations, future legislation or administrative action, or from changes in the policy of FDA or foreign regulatory authorities during the period of product development, clinical trials, and regulatory review by the FDA or foreign regulatory authorities. It is impossible to predict whether legislative changes will

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be enacted, or whether FDA or foreign, regulations, guidance, or interpretations will be changed, or what the impact of such changes, if any, may be.

Because the therapeutic candidates we are developing may represent a new class of therapeutics, we are not aware of any definitive policies, practices, or guidelines that the FDA or its foreign counterparts have established in relation to these drugs. While we believe the therapeutic candidates we are currently developing are regulated as new biological products under the Public Health Service Act, or PHSA, the FDA could decide to regulate them or other products we may develop as drugs under the Federal Food, Drug, and Cosmetic Act, or FDCA. The lack of policies, practices, or guidelines may hinder or slow review by the FDA or foreign regulatory authorities of any regulatory filings we may submit. Moreover, the FDA or foreign regulatory authorities may respond to these submissions by defining requirements we may not have anticipated. Such responses could lead to significant delays in the clinical development of our therapeutic candidates.

Our therapeutic candidates could fail to receive regulatory approval for many reasons, including the following:

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

•we may be unable to demonstrate to the satisfaction of the FDA or comparable foreign regulatory authorities that a therapeutic candidate is safe and effective for its proposed indication;

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

•we may be unable to demonstrate that a therapeutic candidate’s clinical and other benefits outweigh its safety risks, including the safety concerns we have experienced in the NEON-2 trial, which have led to the discontinuation of both the NEON-2 and NEON-1 trials;

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

•the data collected from clinical trials of our therapeutic candidates may not be sufficient to support the submission of a BLA or other submission or to obtain regulatory approval in the United States, the European Union or elsewhere;

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

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

Any delay or failure in obtaining required approvals could have a material adverse effect on our ability to generate revenues from the particular therapeutic candidate for which we are seeking approval. The FDA, the EMA and other regulatory authorities have substantial discretion in the approval process, and in determining when or whether regulatory approval will be obtained for any of our therapeutic candidates. Even if we believe the data collected from preclinical and clinical trials of our therapeutic candidates are promising, such data may not be sufficient to support approval by the FDA, the EMA or any other regulatory authority. Furthermore, any regulatory approval to market a product may be subject to limitations on the approved uses for which we may market the product or in the product labeling or be subject to other restrictions. Regulatory authorities also may impose requirements for costly post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of the therapeutic. In addition, the FDA has the authority to require a REMS plan as part of the approval of a BLA or NDA, or after approval, which may impose further requirements or restrictions on the distribution or use of an approved drug or biologic, such as limiting prescribing to certain physicians or medical centers that have undergone specialized training, limiting treatment to patients who meet certain safe-use criteria, and requiring treated patients to enroll in a registry. These limitations and restrictions may limit the size of the market for the therapeutic and affect coverage and reimbursement by third-party payors.

We are also subject to numerous foreign regulatory requirements governing, among other things, the conduct of clinical trials, manufacturing, marketing authorization, pricing, and third-party reimbursement. The foreign regulatory approval process varies among countries and may include all of the risks associated with FDA approval described above as well as risks attributable to the satisfaction of local regulations in foreign jurisdictions. We are subject to regulation by foreign regulatory authorities, ethics committees, and other governmental entities with respect to the clinical trials we conduct or sponsor outside of the U.S. For example, the EU Clinical Trials Regulation, or CTR, became applicable on January 31, 2022, repealing the EU Clinical Trials Directive. The implementation of the CTR includes the implementation of the Clinical Trials Information System, a new clinical trial portal and database that will be maintained by the EMA in collaboration with the European Commission and the EU Member States. Complying with changes in regulatory requirements can incur additional costs, delay our clinical development plans, or expose us to greater liability if we are slow or unable to adapt to changes in existing

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requirements or new requirements or policies governing our business operations, including our clinical trials. Moreover, the time required to obtain approval may differ from that required to obtain FDA approval. Approval by the FDA does not ensure approval by regulatory authorities outside the U.S. and vice versa.

If we fail to obtain orphan drug designation or obtain or maintain orphan drug exclusivity for certain of our products, our competitors may sell products to treat the same conditions and our revenue may be reduced.

Under the Orphan Drug Act, the FDA may designate a product as an orphan drug if it is intended to treat a rare disease or condition, defined as a patient population of fewer than 200,000 in the United States, or a patient population greater than 200,000 in the United States where there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the United States. In the United States, orphan drug designation entitles a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers. In addition, if a therapeutic product with orphan drug designation subsequently receives the first FDA approval for the indication for which it has such designation, the therapeutic product is entitled to orphan product exclusivity, which means the FDA may not approve any other applications to market the same therapeutic product for the same indication for seven years, except in limited circumstances such as a showing of clinical superiority over the product with orphan exclusivity or where the manufacturer is unable to assure sufficient product quantity.

As in the United States, we may apply for designation of a therapeutic candidate as an orphan drug for the treatment of a specific indication in the European Union before the application for marketing authorization is made. In the European Union, the EMA’s Committee for Orphan Medicinal Products, grants orphan drug designation to promote the development of products that are intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition affecting not more than five in 10,000 persons in the European Union. Additionally, designation is granted for products intended for the diagnosis, prevention or treatment of a life-threatening, seriously debilitating or serious and chronic condition when, without incentives, it is unlikely that sales of the drug in the European Union would be sufficient to justify the necessary investment in developing the drug or biological product or where there is no satisfactory method of diagnosis, prevention or treatment, or, if such a method exists, the medicine must be of significant benefit to those affected by the condition. Sponsors of orphan drugs in the European Union can enjoy economic and marketing benefits, including reduction of fees or fee waivers and up to ten years of market exclusivity for the approved indication unless another applicant can show its therapeutic product is safer, more effective, or otherwise clinically superior to the orphan-designated therapeutic product. This period may be reduced to six years if the orphan drug designation criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity.

We may seek orphan drug designation from the FDA and the EMA for certain of our product candidates. However, we may never receive such designation. Even if we are able to obtain orphan designation, we may not be the first to obtain marketing approval for any particular orphan indication due to the uncertainties associated with developing pharmaceutical products. In addition, exclusive marketing rights in the United States may be limited if we seek approval for an indication broader than the orphan-designated indication or may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition. Further, even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different drugs with different active moieties can be approved for the same condition. Even after an orphan drug is approved, regulatory authorities may subsequently approve the same drug with the same active moiety for the same condition if they conclude that the later drug is safer, more effective, or makes a major contribution to patient care. Orphan drug designation neither shortens the development time or regulatory review time of a product candidate nor gives the product candidate any advantage in the regulatory review or approval process. In addition, orphan drug exclusivity could block the approval of one of our therapeutic candidates if a competitor obtains approval of the same therapeutic product as defined by the FDA before we do, or if our therapeutic candidate is determined to be within the same class as the competitor’s therapeutic product for the same indication or disease.

The respective orphan designation and exclusivity frameworks in the United States and in the European Union are subject to change, and any such changes may affect our ability to obtain EU or U.S. orphan designations in the future.

If we or our existing or future collaborators, manufacturers, or service providers fail to comply with healthcare laws and regulations, we or such other parties could be subject to enforcement actions, which could adversely affect our ability to develop, market, and sell our therapeutics and may harm our reputation.

Although we do not currently have any products on the market, once we begin commercializing our therapeutic candidates, if approved, we will be subject to additional healthcare statutory and regulatory requirements and enforcement by the federal, state, and foreign governments of the jurisdictions in which we conduct our business. Healthcare providers, physicians, and third-party payors play a primary role in the recommendation and prescription of any therapeutic candidates for

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which we obtain marketing approval. Our future arrangements with third-party payors and customers may expose us to broadly applicable fraud, abuse, and other healthcare laws and regulations constraining the business or financial arrangements and relationships through which we market, sell, and distribute the therapeutic candidates for which we obtain marketing approval. Restrictions under applicable federal and state healthcare laws and regulations include the following:

•the U.S. federal Anti-Kickback Statute, which prohibits, among other things, persons from soliciting, receiving, offering, or providing remuneration, directly or indirectly, to induce either the referral of an individual for a healthcare item or service, or the purchasing or ordering of an item or service, for which payment may be made, in whole or in part, under a federal healthcare program such as Medicare or Medicaid;

•the U.S. federal False Claims Act, which imposes criminal and civil penalties, including through civil whistleblower or qui tam actions, against individuals or entities for knowingly presenting, or causing to be presented, to the federal government, false or fraudulent claims for payment or making a false statement to avoid, decrease, or conceal an obligation to pay money to the federal government. In addition, the government may assert a claim including items and services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the False Claims Act;

•state all-payor fraud laws, which impose criminal and civil liability for executing a scheme to defraud any healthcare benefit program, or knowingly and willfully falsifying, concealing, or covering up a material fact or making any materially false statement in connection with the delivery of or payment for healthcare benefits, items or services; similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation;

•HIPAA, HITECH, and their implementing regulations, which impose obligations on certain covered entity healthcare providers, health plans, and healthcare clearinghouses as well as their business associates performing certain services involving the use or disclosure of individually identifiable health information, including mandatory contractual terms, with respect to safeguarding the privacy, security, and transmission of individually identifiable health information, and require notification to affected individuals and regulatory authorities of certain breaches of security of individually identifiable health information;

•the federal Physician Payment Sunshine Act and its implementing regulations, also referred to as “Open Payments,” require applicable manufacturers of pharmaceutical and biological drugs, among other covered medical products, reimbursable under Medicare, Medicaid, or Children’s Health Insurance Programs to track and report to the CMS certain payments and transfers of value made in the previous year, including but not limited to, consulting fees, travel reimbursements, and research grants made to cover recipients, including physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), certain non-physician healthcare professionals (such as physician assistants and nurse practitioners, among others), and teaching hospitals, as well as information regarding physicians’ and their immediate family members’ ownership and investment interests in the applicable manufacturer, with limited exceptions; and

•analogous and similar state and foreign laws and regulations, such as, state anti-kickback and false claims laws potentially applicable to sales or marketing arrangements and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers; and some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government in addition to requiring drug manufacturers to report information related to payments to physicians and other healthcare providers or marketing expenditures.

Ensuring our future business arrangements with third parties comply with applicable healthcare laws and regulations could involve substantial costs. If our operations are found to be in violation of any such requirements, we may be subject to penalties, including civil or criminal penalties, monetary damages, the curtailment or restructuring of our operations, or exclusion from participation in government contracting, healthcare reimbursement, or other government programs, including Medicare and Medicaid, any of which could adversely affect our financial results. Although effective compliance programs can mitigate the risk of investigation and prosecution for violations of these laws, these risks cannot be entirely eliminated. Any action against us for an alleged or suspected violation could cause our company to incur significant legal expenses and could divert our management’s attention from the operation of our business, even if our defense is successful. In addition, achieving and sustaining compliance with applicable laws and regulations may be costly to us in terms of money, time, and resources.

If we or our current or future collaborators, manufacturers, or service providers fail to comply with applicable federal, state, or foreign laws or regulations, we could be subject to enforcement actions, which could affect our ability to develop, market, and sell our therapeutics successfully and could harm our reputation and lead to reduced acceptance of our therapeutics by the market. These enforcement actions include, among others:

•adverse regulatory inspection findings;

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•warning or untitled letters;

•voluntary product recalls with public notification or medical product safety alerts to healthcare professionals;

•restrictions on, or prohibitions against, marketing our therapeutics;

•restrictions on, or prohibitions against, importation or exportation of our therapeutics;

•suspension of review or refusal to approve pending applications or supplements to approved applications;

•exclusion from participation in government-funded healthcare programs;

•exclusion from eligibility for the award of government contracts for our therapeutics;

•FDA debarment;

•suspension or withdrawal of therapeutic approvals;

•seizures or administrative detention of therapeutics;

•injunctions; and

•restitution, disgorgement of profits, or civil and criminal penalties and fines.

Enacted and future legislation may increase the difficulty and cost for us to obtain marketing approval of our therapeutic candidates.

The policies of the FDA or similar regulatory authorities may change, and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. For example, in 2016, the 21st Century Cures Act, or Cures Act, was signed into law. The Cures Act, among other things, is intended to modernize the regulation of drugs and biologics and spur innovation, but it is still being implemented and its ultimate implementation is unclear. If we or our collaborators are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we or our collaborators are not able to maintain regulatory compliance, our therapeutic candidates may not obtain or maintain regulatory approval, and we may not achieve or sustain profitability, which would adversely affect our business.

We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or executive or administrative action, either in the United States or abroad. The FDA’s and other regulatory authorities’ policies may change, and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained, and we may not achieve or sustain profitability. For example, Congress is reviewing the FDA user fee reauthorization bill with new reforms to the accelerated approval pathway. If the reauthorization bill is not passed before the current user fee legislation expires at the end of September 2022, FDA may face layoffs, which can have a material impact on our clinical development plans and our business. It is difficult to predict how current and future legislation, executive actions, and litigation, including the executive orders, will be implemented, and the extent to which they will impact our business, our clinical development, and the FDA’s and other agencies’ ability to exercise their regulatory authority, including FDA’s pre-approval inspections and timely review of any regulatory filings or applications we submit to the FDA. To the extent any legislative or executive actions impose constraints on FDA’s ability to engage in oversight and implementation activities in the normal course, our business may be negatively impacted.

Any therapeutics we develop may become subject to unfavorable pricing regulations, third-party coverage and reimbursement practices, or healthcare reform initiatives, thereby harming our business.

The regulations governing marketing approvals, pricing, coverage, and reimbursement for new drugs and biologics vary widely from country to country. Many countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted. In some foreign markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. Although we intend to monitor these regulations, our programs are currently in the early stages of development and we will not be able to assess the impact of price regulations for a number of years. As a result, we might obtain regulatory approval for a product in a particular country but then be subject to price regulations delaying our commercial launch of the product and negatively impacting the revenues we are able to generate from the sale of the product in that country.

Our ability to commercialize any therapeutics successfully also will depend in part on the extent to which coverage and reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers, and other organizations. However, there may be significant delays in obtaining coverage for

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newly-approved therapeutics. Moreover, eligibility for coverage does not necessarily signify a therapeutic will be reimbursed in all cases or at a rate covering our costs, including research, development, manufacture, sale, and distribution costs. Also, interim payments for new therapeutics, if applicable, may be insufficient to cover our costs and may not be made permanent. Thus, even if we succeed in bringing one or more therapeutics to the market, these products may not be considered cost-effective, and the amount reimbursed for any of them may be insufficient to allow us to sell them on a competitive basis. Because our programs are in the early stages of development, we are unable at this time to determine their cost effectiveness, coverage prospects, potential compendia listings, or the likely level or method of reimbursement, if covered. It is equally difficult for us to predict how Medicare coverage and reimbursement policies will be applied to our products in the future, and coverage and reimbursement under different federal healthcare programs are not always consistent. Medicare reimbursement rates may also reflect budgetary constraints placed on the Medicare program.

Third-party payors often rely upon Medicare coverage policies and payment limitations in setting their own reimbursement rates. These coverage policies and limitations may rely, in part, on compendia listings for approved therapeutics. Our inability to promptly obtain relevant compendia listings, coverage, and adequate reimbursement from both government-funded and private payors for new therapeutics we develop and for which we obtain regulatory approval could have a material adverse effect on our operating results, our ability to raise capital needed to commercialize products, and our financial condition.

We believe the efforts of governments and third-party payors to contain or reduce the cost of healthcare, and legislative and regulatory proposals to broaden the availability of healthcare, will continue to affect the business and financial condition of pharmaceutical and biopharmaceutical companies. A number of legislative and regulatory changes in the healthcare system in the United States and other major healthcare markets have been proposed or enacted, and such efforts have expanded substantially in recent years. These developments could, directly or indirectly, affect our ability to sell our products, if approved, at a favorable price. In addition, third-party payors who reimburse patients or healthcare providers, such as government and private insurance plans, are seeking greater upfront discounts, additional rebates, and other concessions to reduce the prices for therapeutics. If the price we are able to charge for any therapeutics we develop, or the reimbursement provided for such products, is inadequate, our return on investment could be adversely affected.

Pursuant to health reform legislation and related initiatives, the Centers for Medicare and Medicaid Services, or CMS, are working with various healthcare providers to develop, refine, and implement Accountable Care Organizations, or ACOs, and other innovative models of care for Medicare and Medicaid beneficiaries, including the Bundled Payments for Care Improvement Initiative, the Comprehensive Primary Care Initiative, the Duals Demonstration, and other models. The continued development and expansion of ACOs and other innovative models of care will have an uncertain impact on any future reimbursement we may receive for approved therapeutics administered by such organizations.

In addition, in recent years, the U.S. Congress has enacted various laws seeking to reduce the federal debt level and contain healthcare expenditures. For example, as a result of the Budget Control Act of 2011 and the Bipartisan Budget Act of 2015, an annual 2% reduction to Medicare payments that took effect in 2013 and will remain in effect through 2031, with the exception of a temporary suspension implemented under various COVID-19 relief legislation from May 1, 2020 through March 31, 2022. Under current legislation, the actual reduction in Medicare payments will vary from 1% in 2022 to up to 4% in the final fiscal year of this sequester. These across-the-board spending cuts could adversely affect our future revenues, earnings, and cash flows.

There has been increasing legislative and enforcement interest in the United States with respect to specialty drug pricing practices. Specifically, there have been several recent U.S. Congressional inquiries and proposed federal and state legislation designed to, among other things, bring more transparency to drug pricing, reduce the cost of prescription drugs under Medicare, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drugs. For example, under the American Rescue Plan Act of 2021, effective January 1, 2024, the statutory cap on Medicaid Drug Rebate Program rebates that manufacturers pay to state Medicaid programs will be eliminated. Elimination of this cap may require pharmaceutical manufacturers to pay more in rebates than it receives on the sale of products, which could have a material impact on our business. In July 2021, the Biden administration released an executive order, “Promoting Competition in the American Economy,” with multiple provisions aimed at increasing competition for prescription drugs. In August 2022, Congress passed the Inflation Reduction Act of 2022, which includes prescription drug provisions that have significant implications for the pharmaceutical industry and Medicare beneficiaries, including allowing the federal government to negotiate a maximum fair price for certain high-priced single source Medicare drugs, imposing penalties and excise tax for manufacturers that fail to comply with the drug price negotiation requirements, requiring inflation rebates for all Medicare Part B and Part D drugs, with limited exceptions, if their drug prices increase faster than inflation, and redesigning Medicare Part D to reduce out-of-pocket prescription drug costs for beneficiaries, among other changes. The impact of these legislative, executive, and administrative actions and any future healthcare measures and agency rules implemented by the Biden administration on us and the pharmaceutical industry as a whole is unclear. Any reduction in reimbursement from Medicare or other government programs may result in a reduction in payments from private payors. Additionally, a number of

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states are considering or have recently enacted state drug price transparency and reporting laws that could substantially increase our compliance burdens and expose us to greater liability under such state laws once we begin commercialization after obtaining regulatory approval for any of our products.

The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability or commercialize our product candidates. The impact of legislative, executive, and administrative actions of the Biden administration on us and the biopharmaceutical industry as a whole is unclear. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our product candidates or additional pricing pressures.

The healthcare industry is heavily regulated in the U.S. at the federal, state, and local levels and in other jurisdictions in which we may conduct trials or other activities, and our failure to comply with applicable requirements may subject us to penalties and negatively affect our financial condition.

As a healthcare company, our operations, clinical trial activities, and interactions with healthcare providers will be subject to extensive regulation in the United States, particularly if we receive FDA approval for any of our products in the future, and we may be subject to laws and regulations in other jurisdictions as we conduct clinical trials or engage in other activities in foreign jurisdictions. For example, if we receive FDA approval for a therapeutic for which reimbursement is available under a federal healthcare program, it would be subject to a variety of federal laws and regulations, including those prohibiting the filing of false or improper claims for payment by federal healthcare programs, prohibiting unlawful inducements for the referral of business reimbursable by federal healthcare programs, and requiring disclosure of certain payments and other transfers of value made to covered recipients in the previous year, including U.S.-licensed physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), certain non-physician healthcare professionals (such as physician assistants and nurse practitioners, among others), and teaching hospitals, as well as information regarding certain physicians’ and their immediate family members’ ownership and investment interests in the applicable manufacturer with limited exceptions. If our past or present operations, or those of our contractors or agents who conduct business on our behalf, are found to be in violation of any of these laws, we could be subject to enforcement action, government investigation, civil and criminal penalties, which could hurt our business, operations, and financial condition. It is not always possible to identify and deter misconduct by parties we may contract with, including employees, contractors, collaborators, CROs, and suppliers, and the precautions we take to detect and prevent misconduct may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant penalties, including civil, criminal and administrative penalties, damages, fines, disgorgement, imprisonment, exclusion from participation in government funded healthcare programs, such as Medicare and Medicaid, integrity oversight and reporting obligations, contractual damages, reputational harm, diminished profits and future earnings and the curtailment or restructuring of our operations.

Similarly, some state laws prohibit, among other offenses, knowingly and willfully executing a scheme to defraud any health care benefit program, including private payors, or falsifying, concealing, or covering up a material fact or making any materially false, fictitious, or fraudulent statement in connection with the delivery of or payment for items or services under a health care benefit program. We may also be subject to the privacy and security provisions of HIPAA, as amended by HITECH, which restricts the use and disclosure of patient-identifiable health information, mandates the adoption of standards relating to the privacy and security of patient-identifiable health information, and requires the reporting of certain security breaches to healthcare provider customers with respect to such information. Additionally, many states have enacted similar laws imposing more stringent requirements on entities like us. Failure to comply with applicable laws and regulations could result in substantial penalties and adversely affect our financial condition and results of operations. Complying with new regulatory requirements and changes in the laws and regulations will increase our compliance cost and exposure to potential liability.

Additionally, the collection and use of health data in the EU is governed by the General Data Protection Regulation, or GDPR, which extends the geographical scope of EU data protection law to non-EU entities under certain conditions and imposes substantial obligations upon companies and new rights for individuals. Further, state and foreign laws may apply generally to the privacy and security of information we maintain, and may differ from each other in significant ways, thus complicating compliance efforts, as discussed in the risk factor below titled, “Data collection is governed by restrictive regulations governing the use, processing and cross-border transfer of personal information, and actual or perceived failures to comply with applicable data protection, privacy and security laws, regulations, standards and other requirements could adversely affect our business, results of operations and financial condition.”

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Data collection is governed by restrictive regulations governing the use, processing and cross-border transfer of personal information, and actual or perceived failures to comply with applicable data protection, privacy and security laws, regulations, standards and other requirements could adversely affect our business, results of operations and financial condition.

The global data protection landscape is rapidly evolving, and we are or may become subject to numerous state, federal and foreign laws, regulations, and other actual and asserted obligations governing the collection, use, disclosure, retention, and security of personal information, such as information collected or otherwise processed in connection with clinical trials in the U.S. and abroad. Implementation standards and enforcement practices are likely to remain uncertain for the foreseeable future, and we cannot yet determine the impact future laws, regulations, standards, or other actual or asserted obligations, or any perception of their requirements may have on our business. This evolution may create uncertainty in our business, affect our ability to operate in certain jurisdictions or to collect, store, transfer use and share personal information, necessitate the acceptance of more onerous obligations in our contracts, result in liability or impose additional costs on us. The cost of compliance with these laws, regulations, standards, and obligations is high and is likely to increase in the future. Any failure or perceived failure by us to comply with federal, state or foreign laws or regulations, our internal policies and procedures, our contractual obligations governing our processing of personal information, or any other standards or other actual or asserted obligations, could result in negative publicity, government investigations and enforcement actions, claims by third parties and damage to our reputation, any of which could have a material adverse effect on our business, results of operation, and financial condition.

In conducting and/or enrolling patients in our current or future clinical trials, we are subject to restrictions relating to privacy, data protection and data security and may be subject to additional restrictions as our clinical operations expand. For example, the collection, use, storage, disclosure, transfer, or other processing of personal data regarding individuals in the European Economic Area, or EEA, including personal health data, is subject to the GDPR. The GDPR is wide-ranging in scope and imposes numerous requirements on companies that process personal data, including requirements relating to processing health and other sensitive data, obtaining consent of the individuals to whom the personal data relates, providing information to individuals regarding data processing activities, implementing safeguards to protect the security and confidentiality of personal data, providing notification of data breaches (initially to supervisory authorities and, if the breach is serious enough, to individuals), and taking certain measures when engaging third-party processors. The GDPR also imposes strict rules on the transfer of personal data to countries outside the EEA, including the United States, and permits data protection authorities to impose large penalties for violations of the GDPR, including potential fines of up to €20 million or 4% of annual global revenues, whichever is greater, for the most serious of violations. The GDPR also confers a private right of action on data subjects and consumer associations to lodge complaints with supervisory authorities, seek judicial remedies, and obtain compensation for damages resulting from violations of the GDPR. In addition, the GDPR includes restrictions on cross-border data transfers. Certain aspects of cross-border data transfers under the GDPR are uncertain as the result of legal proceedings in the EU, including a July 2020 decision by the Court of Justice for the European Union, or CJEU, that invalidated the EU-U.S. Privacy Shield and, to some extent, called into question the efficacy and legality of using standard contractual clauses approved by the European Commission, or SCCs. To address certain concerns of the CJEU, the European Commission issued revised SCCs in June 2021 that are required to be implemented over time. Regulatory guidance and other developments relating to cross-border personal data transfers, including the necessity of putting in place those revised SCCs and UK SCCs, as discussed below, may increase the complexity of transferring personal data across borders and may require us to engage in additional contractual negotiations and to modify our policies and practices relating to the transfer and other processing of personal data. The GDPR increased our responsibility and liability in relation to personal data that we process where such processing is subject to the GDPR, and we may be required to put in place additional mechanisms to ensure compliance with the GDPR, including as implemented by individual countries.

In the United Kingdom, or UK, the Data Protection Act of 2018 is effective along with a version of the GDPR referred to as the UK GDPR. Collectively, the Data Protection Act of 2018 and the UK GDPR authorize significant fines, up to the greater of £17.5 million or 4% of global turnover, and expose us to two parallel regimes and other potentially divergent enforcement actions for certain violations. Further, aspects of data protection in the UK remain uncertain. On June 28, 2021, the European Commission issued an adequacy decision under the GDPR and the Law Enforcement Directive, pursuant to which personal data generally may be transferred from the EU to the UK without restriction; however, this adequacy decision is subject to a four-year “sunset” period, after which the European Commission’s adequacy decision may be renewed, and this decision may be revoked or modified in the interim. Additionally, on February 2, 2022, the UK’s Information Commissioner’s Office issued new standard contractual clauses to support personal data transfers out of the UK, or the UK SCCs. The UK SCCs became effective March 21, 2022 and, similar to the EU SCCs, are required to be implemented over time. We may, in addition to other impacts, experience additional costs associated with increased compliance burdens and be required to engage in new contract negotiations with third parties that aid in processing personal data on our behalf or localize certain personal data.

Other jurisdictions also increasingly maintain laws and regulations addressing privacy, data protection, and information security. We may incur liabilities, expenses, costs, and other operational losses under GDPR and local laws of

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applicable EU member states, the UK, and other regions in connection with any measures we take to comply with them. Working to comply with the GDPR and other laws and regulations to which we are subject in Europe and other regions outside the United States relating to privacy, data protection, and information security will be a rigorous and time-intensive process that may increase our cost of doing business or require us to change our business practices, and despite those efforts, there is a risk that we may be subject to fines and penalties, litigation, and reputational harm in connection with our activities in those regions.

In addition, in California, the CCPA creates new individual privacy rights for California consumers (as defined in the law) and places increased privacy and security obligations on entities handling personal data of consumers or households. The CCPA requires covered companies to provide new disclosure to consumers about such companies’ data collection, use and sharing practices, provide such consumers new ways to opt-out of certain sales or transfers of personal information, and provide consumers with additional causes of action in data breach situations. While it exempts some data regulated by HIPAA and certain clinical trial data, the CCPA, to the extent applicable to our business and operations, may increase our compliance costs and potential liability with respect to other personal information we collect about California residents. The CCPA went into effect on January 1, 2020, and the California Attorney General commenced enforcement actions for violations on July 1, 2020. Moreover, the CPRA was approved by California voters in the November 3, 2020 election. The CPRA will significantly modify the CCPA, creating obligations beginning on January 1, 2022, with enforcement anticipated to commence July 1, 2023. The CPRA creates further uncertainty and may require us to incur additional costs and expenses. The CCPA and CPRA could mark the beginning of a trend toward more stringent privacy legislation in the United States. The CCPA has prompted a number of proposals for federal and state privacy legislation. For example, in March 2021, Virginia enacted the Virginia Consumer Data Protection Act, or CDPA, a comprehensive privacy statute that becomes effective on January 1, 2023. In addition, on July 7, 2021, Colorado enacted the Colorado Privacy Act, or CPA, becoming the third state to pass comprehensive consumer privacy legislation in the United States, which becomes effective July 1, 2023, on March 24, 2022, Utah enacted the Utah Consumer Privacy Act, or UCPA, which becomes effective December 31, 2023, and on May 10, 2022, Connecticut enacted the Act Concerning Personal Data Privacy and Online Monitoring, or CPOMA, which becomes effective July 1, 2023. The CDPA, CPA, UCPA, and CPOMA are comprehensive privacy statutes that share similarities with the CCPA and CPRA. The U.S. federal government also is contemplating federal privacy legislation. These and other new laws that may be proposed or enacted could increase our potential liability and adversely affect our business.

Compliance with U.S. and international data protection laws and regulations could require us to take on more onerous obligations in our contracts, restrict our ability to collect, use and disclose data, or in some cases, impact our ability to operate in certain jurisdictions. Any actual or alleged failure to comply with U.S. or international laws and regulations relating to privacy, data protection, and data security could result in governmental investigations, proceedings and enforcement actions (which could include civil or criminal penalties), private litigation or adverse publicity, harm to our reputation, and could negatively affect our operating results and business. Moreover, clinical trial subjects about whom we or our potential collaborators obtain information, as well as the providers who share this information with us, may contractually limit our ability to use and disclose the information or impose other obligations or restrictions in connection with our use, retention and other processing of information, and we may otherwise face contractual restrictions applicable to our use, retention, and other processing of information. Claims that we have violated individuals’ privacy rights, failed to comply with data protection laws, or breached our contractual obligations, even if we are not found liable, could be expensive and time-consuming to defend and could result in adverse publicity that could harm our business.

Our ability to obtain services, reimbursement, or funding from the federal government may be impacted by possible reductions in federal spending.

The U.S. federal budget remains in flux and could, among other things, cut Medicare payments to providers. The Medicare program is frequently mentioned as a target for spending cuts. The full impact on our business of any future cuts in Medicare or other programs is uncertain. We cannot predict the extent of legislative, executive, and administrative actions of the Biden administration will have on us and the biopharmaceutical industry as a whole. If federal spending is reduced, anticipated budgetary shortfalls may also impact the ability of relevant agencies such as the FDA or the National Institutes of Health to continue to function at current levels. Amounts allocated to federal grants and contracts may be reduced or eliminated. These reductions may also impact the ability of relevant agencies to timely review and approve drug research and development, manufacturing, and marketing activities, which may delay our ability to develop, market, and sell any therapeutics we may develop.

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If any of our therapeutic candidates receives marketing approval and we or others later identify undesirable side effects caused by the therapeutic product, our ability to market and derive revenue from the therapeutic products could be compromised.

In the event any of our therapeutic candidates receive regulatory approval and we or others identify undesirable side effects, adverse events, or other problems caused by one of our therapeutics, any of the following adverse events could occur, which could result in the loss of significant revenue to us and materially and adversely affect our results of operations and business:

•regulatory authorities may withdraw their approval of the product and require us to take the product off the market or seize the product;

•we may need to recall the therapeutic or change the way the therapeutic is administered to patients;

•additional restrictions may be imposed on the marketing and promotion of the particular therapeutic or the manufacturing processes for the therapeutic or any component thereof;

•we may not be able to secure or maintain adequate coverage and reimbursement for our proprietary therapeutic products from government (including U.S. federal health care programs) and private payors;

•we may lose or see adverse alterations to compendia listings or treatment protocols specified by accountable care organizations;

•we may be subject to fines, restitution, or disgorgement of profits or revenues, injunctions, or the imposition of civil penalties or criminal prosecution;

•regulatory authorities may require the addition of labeling statements, such as a “black box” warning, or equivalent, or a contraindication;

•regulatory authorities may require us to implement a REMS plan, or to conduct post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of the product;

•we may be required to create a Medication Guide outlining the risks of such side effects for distribution to patients;

•we could be sued and held liable for harm caused to patients;

•the therapeutic may become less competitive; and

•our reputation may suffer.

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

The Patient Protection and Affordable Care Act, signed into law in 2010, includes a subtitle called the Biologics Price Competition and Innovation Act of 2009, or BPCIA, which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of their product. The law is complex and is still being interpreted and implemented by the FDA. As a result, its ultimate impact, implementation, and meaning are subject to uncertainty. While it is uncertain when such processes intended to implement BPCIA may be fully adopted by the FDA, any such processes could have a material adverse effect on the future commercial prospects for our biological products.

We believe that any of our therapeutic candidates approved as a biological product under a BLA should qualify for the 12-year period of exclusivity. However, there is a risk that this exclusivity could be shortened due to congressional action or otherwise, or that the FDA will not consider our therapeutic candidates to be reference products for competing products, potentially creating the opportunity for generic competition sooner than anticipated. Other aspects of the BPCIA, some of which may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of our reference products in a way that is similar to traditional generic substitution for non-biological products is not yet clear, and will depend on a number of marketplace and regulatory factors that are still developing.

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Significant developments stemming from the United Kingdom’s withdrawal from the European Union could have a material adverse effect on us.

The United Kingdom’s withdrawal from the European Union and ongoing negotiations related to the United Kingdom’s trade and other relationships with the European Union continue to create political and economic uncertainty, particularly in the United Kingdom and the European Union. Any business we conduct, now and in the future, in the United Kingdom, the European Union, and worldwide could be affected as a result of this transition and there are multiple ways in which our business could be negatively affected.

Brexit is expected to disrupt the operation of pre- and post-authorization clinical trial infrastructure. As of January 1, 2021, European Union law applies only to the territory of Northern Ireland to the extent foreseen in the Protocol on Ireland / Northern Ireland. The rules around GMP and pharmacovigilance in the UK currently remain similar to the EU requirements. However, the Falsified Medicines Directive will not apply in Great Britain though it is likely that the UK will implement a procedure to minimize the risk of falsified medicines. Uncertainty in the regulatory framework and future legislation can lead to disruption in the execution of international multi-center clinical trials, the monitoring of adverse events in through pharmacovigilance programs, and determination of marketing authorization across different jurisdictions. There could also be disruption to the supply and distribution as well as the import/export both of active pharmaceutical ingredients and finished product. Such a disruption could create supply difficulties for ongoing clinical trials and may damage the integrity of the pharmacovigilance database for the safety of new products. The cumulative effects of the disruption to the regulatory framework, uncertainty in future regulation, and changes to existing regulations may add considerably to the development lead time to marketing authorization and commercialization of products in the European Union and/or the United Kingdom and increase our costs. We cannot predict the impact of such changes and future regulation on our business or the results of our operations. Exposure to different and changing regulations in multiple foreign jurisdictions may increase our liabilities, expenses, costs, and other operational losses.

Risks Related to Ownership of Our Common Stock

Our stock price may be volatile, and an active, liquid, and orderly trading market may not develop for our common stock. As a result, stockholders may not be able to resell shares at or above their purchase price.

Although our common stock is listed on the Nasdaq Global Market, an active trading market for our common stock may not be sustained. The lack of an active market may impair the ability of our stockholders to sell their shares at the time they wish to sell them or at a price that they consider reasonable, which may reduce the fair market value of their shares. Further, an inactive market may also impair our ability to raise capital by selling our common stock should we determine additional funding is required.

The market price of our common stock could be subject to significant fluctuations. Market prices for securities of early-stage pharmaceutical, biotechnology, and other life sciences companies have historically been particularly volatile. Some of the factors that may cause the market price of our common stock to fluctuate include:

•our and our collaborators’ ability to obtain regulatory approvals for product candidates, and delays or failures to obtain such approvals;

•the failure of any of our product candidates, if approved, to achieve commercial success;

•issues in manufacturing our approved products, if any, or product candidates;

•the results of current, and any future, preclinical or clinical trials of our product candidates;

•our ability to achieve development milestones and receive associated milestone payments pursuant to the terms of our collaboration agreements;

•the entry into, or termination of, key agreements, including key licensing, collaboration or acquisition agreements;

•the initiation or material developments in, or conclusion of, litigation to enforce or defend any of our intellectual property rights or defend against the intellectual property rights of others;

•announcements by commercial partners or competitors of new commercial products, clinical progress (or the lack thereof), significant contracts, commercial relationships, or capital commitments;

•adverse publicity relating to our markets, including with respect to other products and potential products in such markets;

•adverse publicity about our company, employees, therapeutic candidates, and/or therapeutic products in the media or on social media;

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•the impact of COVID-19 on our company or the economy generally;

•the introduction of technological innovations or new therapies competing with our potential products;

•the loss of key employees;

•changes in estimates or recommendations by securities analysts, if any, who cover our common stock;

•general and industry-specific economic conditions potentially affecting our research and development expenditures;

•changes in the structure of health care payment systems;

•unanticipated serious safety concerns related to the use of any of our product candidates, including those we have experienced in the NEON-2 trial, which resulted in the recent discontinuation of the NEON-2 and NEON-1 trials;

•failure to meet or exceed financial and development projections we may provide to the public;

•failure to meet or exceed the financial and development projections of the investment community;

•the perception of the pharmaceutical industry by the public, legislators, regulators, and the investment community;

•adverse regulatory decisions;

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

•commencement of, or our involvement in, litigation;

•sales of our common stock by us or our stockholders in the future;

•trading volume of our common stock;

•period-to-period fluctuations in our financial results; and

•the other factors described in this “Risk Factors” section.

Moreover, the stock markets in general have experienced substantial volatility that has often been unrelated to the operating performance of individual companies or the biotechnology sector. These broad market fluctuations may also adversely affect the trading price of our common stock.

In the past, following periods of volatility in the market price of a company’s securities, stockholders have often instituted class action securities litigation against those companies. Such litigation, if instituted, could result in substantial costs and diversion of management attention and resources, which could significantly harm our business and reputation.

Our officers and directors, and their respective affiliates, have significant influence over our business affairs and may make business decisions with which stockholders disagree and which may adversely affect the value of their investment.

Our executive officers and directors together with their respective affiliates, beneficially own approximately 44% of our common stock as of September 30, 2022. As a result, if some of these persons or entities act together, they will have the ability to exercise significant influence over matters submitted to the stockholders for approval, including the election of directors, amendments to the certificate of incorporation and bylaws and the approval of any strategic transaction requiring the approval of the stockholders. These actions may be taken even if they are opposed by other stockholders. This concentration of ownership may also have the effect of delaying or preventing a change of control of our company or discouraging others from making tender offers for our shares, which could prevent our stockholders from receiving a premium for their shares. Some of these persons or entities who make up our principal stockholders may have interests different from other stockholders. The significant concentration of stock ownership may adversely affect the trading price of our common stock due to investors’ perception that conflicts of interest may exist or arise.

Future sales, or the perception of future sales, of a substantial amount of our common stock could depress the trading price of our common stock.

Our stock price could decline as a result of sales of a large number of shares of our common stock or the perception that these sales could occur. These sales, or the possibility that these sales may occur, also might make it more difficult for us to sell equity securities in the future at a time and at a price that we deem appropriate.

For example, in connection with our July 2020 private placement, we entered into a registration rights agreement with the private placement investors that required us to prepare and file a resale registration statement, which was declared effective

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by the SEC on August 18, 2020 and permits the resale by the private placement investors of approximately 5.1 million shares of our common stock as well as approximately 2.6 million shares of common stock issuable upon the exercise of prefunded warrants and warrants issued in the July 2020 private placement. Additionally, in connection with our September 2021 private placement, we entered into a registration rights agreement with the private placement investors that required us to prepare and file a resale registration statement, which was declared effective by the SEC on November 19, 2021 and permits the resale by the private placement investors of approximately 6.5 million shares of our common stock as well as approximately 3.2 million shares of common stock issuable upon the exercise of prefunded warrants issued in the September 2021 private placement. We have in the past and may again in the future sell shares of our common stock to strategic partners in connection with collaboration agreements, as we did in December 2021 in connection with our agreement with Horizon. The shares subject to outstanding options and warrants, of which options and warrants (including prefunded warrants) to purchase 3.7 million shares and 8.8 million shares, respectively, were exercisable as of September 30, 2022, and the shares reserved for future issuance under our equity incentive plans will become available for sale immediately upon the exercise of such options.

We also register the offer and sale of all shares of common stock that we may issue under our equity incentive plans. Once we register the offer and sale of shares for the holders of registration rights and option holders, they can be freely sold in the public market upon issuance, subject to any related lock-up agreements or applicable securities laws.

In addition, in the future, we may issue additional shares of common stock or other equity or debt securities convertible into common stock in connection with a financing, acquisition, litigation settlement, employee arrangements or otherwise. Any such future issuance could result in substantial dilution to our existing stockholders and could cause our stock price to decline.

We have broad discretion over the use of the proceeds to us from our financing activities and may apply the proceeds to uses that do not improve our operating results or the value of your securities.

We have broad discretion over the use of proceeds to us from our financing activities and our stockholders rely solely on the judgment of our board of directors and management regarding the application of these proceeds. Our use of proceeds may not improve our operating results or increase the value of our common stock. Any failure to apply these proceeds effectively could have a material adverse effect on our business, delay the development of our product candidates and cause the market price of our common stock to decline.

Anti-takeover provisions in our charter documents and under Delaware or Washington law could discourage, delay or prevent a change in control of our company, limit attempts by our stockholders to replace or remove our current management and may affect the trading price of our common stock.

Our corporate documents contain provisions that may delay or discourage transactions involving an actual or potential change in our control or change in our management, including transactions in which stockholders might otherwise receive a premium for their shares, or transactions that our stockholders might otherwise deem to be in their best interests. Therefore, these provisions could adversely affect the price of our stock. Among other things, our certificate of incorporation and bylaws:

•stagger the terms of our board of directors and require 66 and 2/3% stockholder voting to remove directors, who may only be removed for cause;

•provide that the authorized number of directors may be changed only by resolution of the board of directors;

•provide that all vacancies, including newly-created directorships, may, except as otherwise required by law, be filled by the affirmative vote of a majority of directors then in office, even if less than a quorum;

•authorize our board of directors to issue “blank check” preferred stock and to determine the rights and preferences of those shares, which may be senior to our common stock, without prior stockholder approval;

•establish advance notice requirements for nominating directors and proposing matters to be voted on by stockholders at stockholders’ meetings;

•prohibit our stockholders from calling a special meeting and prohibit stockholders from acting by written consent;

•require 66 and 2/3% stockholder voting to effect certain amendments to our certificate of incorporation and bylaws; and

•prohibit cumulative voting in the election of directors, which limits the ability of minority stockholders to elect director candidates.

In addition, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, or DGCL, which generally prohibits a Delaware corporation from engaging in any of a

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broad range of business combinations with any “interested” stockholder for a period of three years following the date on which the stockholder became an “interested” stockholder. Likewise, because our principal executive offices are located in Washington, the anti-takeover provisions of the Washington Business Corporation Act may apply to us under certain circumstances now or in the future. These provisions prohibit a “target corporation” from engaging in any of a broad range of business combinations with any stockholder constituting an “acquiring person” for a period of five years following the date on which the stockholder became an “acquiring person.” These provisions could discourage, delay or prevent a transaction involving a change in control of our company. These provisions could also discourage proxy contests and make it more difficult for stockholders to elect directors of their choosing and cause us to take other corporate actions our stockholders desire.

Claims for indemnification by our directors and officers may reduce our available funds to satisfy successful third-party claims against us and may reduce the amount of available cash.

Our amended and restated certificate of incorporation provides that we will indemnify our directors to the fullest extent permitted by Delaware law.

In addition, as permitted by Section 145 of the DGCL, our amended and restated bylaws and our indemnification agreements that we have entered into with our directors and officers provide that:

•We will indemnify our directors and officers for serving us in those capacities or for serving other business enterprises at our request, to the fullest extent permitted by Delaware law. Delaware law provides that a corporation may indemnify such person if such person acted in good faith and in a manner such person reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to any criminal proceeding, had no reasonable cause to believe such person’s conduct was unlawful.

•We may, in our discretion, indemnify other employees and agents in those circumstances where indemnification is permitted by applicable law.

•We are required to advance expenses, as incurred, to our directors and officers in connection with defending a proceeding, except that such directors or officers shall undertake to repay such advances if it is ultimately determined that such person is not entitled to indemnification.

•We will not be obligated pursuant to our amended and restated bylaws to indemnify any director or officer in connection with any proceeding (or part thereof) initiated by such person unless the proceeding was authorized in the specific case by our board of directors or such indemnification is required to be made pursuant to our amended and restated bylaws.

•The rights conferred in our amended and restated bylaws are not exclusive, and we are authorized to enter into indemnification agreements with our directors, officers, employees and agents and to obtain insurance to indemnify such persons.

•We may not retroactively amend our amended and restated bylaw provisions to reduce our indemnification obligations to our directors or officers.

As a result, if we are required to indemnify one or more of our directors or officers, it may reduce our available funds to satisfy successful third-party claims against us, may reduce the amount of available cash and may have a material adverse effect on our business and financial condition.

Our amended and restated certificate of incorporation designates the Court of Chancery of the State of Delaware as the sole and exclusive forum for certain types of actions and proceedings that may be initiated by our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers, employees or agents.

Our amended and restated certificate of incorporation provides that, unless we consent in writing to an alternative forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any derivative action or proceeding brought on our behalf, any action asserting a claim of breach of a fiduciary duty owed by any of our directors, officers, employees or agents to us or our stockholders, any action asserting a claim arising pursuant to any provision of the DGCL, our amended and restated certificate of incorporation or our amended and restated bylaws or any action asserting a claim that is governed by the internal affairs doctrine, in each case subject to the Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein and the claim not being one which is vested in the exclusive jurisdiction of a court or forum other than the Court of Chancery or for which the Court of Chancery does not have subject matter jurisdiction. Any person purchasing or otherwise acquiring any interest in any shares of our common stock shall be deemed to have notice of and to have consented to this provision of our amended and restated certificate of incorporation. In

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addition, our amended and restated bylaws provide that the U.S. federal district courts will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act.

These choice of forum provision may limit our stockholders’ ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers, employees or agents, which may discourage such lawsuits against us and our directors, officers, employees and agents even though an action, if successful, might benefit our stockholders. Stockholders who do bring a claim in the Court of Chancery could face additional litigation costs in pursuing any such claim, particularly if they do not reside in or near Delaware. The Court of Chancery may also reach different judgments or results than would other courts, including courts where a stockholder considering an action may be located or would otherwise choose to bring the action, and such judgments or results may be more favorable to us than to our stockholders. Alternatively, if a court were to find these choice of forum provisions in our amended and restated certificate of incorporation and amended and restated bylaws inapplicable to, or unenforceable in respect of, one or more of the specified types of actions or proceedings, we may incur additional costs associated with resolving such matters in other jurisdictions, which could have a material adverse effect on our business, financial condition or results of operations.

We do not expect to pay any dividends on our common stock for the foreseeable future.

We currently expect to retain all future earnings, if any, for future operations and expansion, and have no current plans to pay any cash dividends to holders of our common stock for the foreseeable future. Any decision to declare and pay dividends in the future will be made at the discretion of our board of directors and will depend on, among other things, our results of operations, financial condition, cash requirements, contractual restrictions and other factors that our board of directors may deem relevant. As a result, stockholders may not receive any return on an investment in our common stock unless stockholders sell our common stock for a price greater than that which they paid for it.

The Nasdaq Global Market may delist our common stock from its exchange, which could limit investors’ ability to make transactions in our securities and subject us to additional trading restrictions.

Our shares of common stock are listed on the Nasdaq Global Market under the trading symbol “ALPN.” Our securities may fail to meet the continued listing requirements to be listed on the Nasdaq Global Market. If Nasdaq delists our shares of common stock from trading on its exchange, we could face significant material adverse consequences, including:

•significant impairment of the liquidity for our common stock, which may substantially decrease the market price of our common stock;

•a limited availability of market quotations for our securities;

•a determination that our common stock qualifies as a “penny stock” which will require brokers trading in our common stock to adhere to more stringent rules and possibly resulting in a reduced level of trading activity in the secondary trading market for our common stock;

•a limited amount of news and analyst coverage for our company; and

•a decreased ability to issue additional securities or obtain additional financing in the future.

Risks Related to Our Financial Reporting and Disclosure

We are a smaller reporting company, and any decision on our part to comply only with reduced reporting and disclosure requirements applicable to such companies could make our common stock less attractive to investors.

We are a “smaller reporting company,” as defined in the Securities Exchange Act of 1934, as amended, or the Exchange Act. For as long as we continue to be a smaller reporting company, we may choose to take advantage of exemptions from various reporting requirements applicable to other public companies that are not smaller reporting companies, including, but not limited to, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements.

We will remain a smaller reporting company so long as, as of June 30 of the preceding year, (i) the market value of our shares of common stock held by non-affiliates, or our public float, is less than $250 million; or (ii) we have annual revenues less than $100 million and either we have no public float or our public float is less than $700 million.

If we take advantage of some or all of the reduced disclosure requirements available to smaller reporting companies, investors may find our common stock less attractive, which may result in a less active trading market for our common stock and greater stock price volatility. For so long as we are a smaller reporting company and not classified as an “accelerated filer” or

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“large accelerated filer” pursuant to SEC rules, we will continue to be exempt from the auditor attestation requirements of Section 404(b) of Sarbanes-Oxley.

If we fail to maintain proper and effective internal controls, our ability to produce accurate financial statements on a timely basis could be impaired.

We are subject to the reporting requirements of the Exchange Act, the Sarbanes-Oxley Act and the rules and regulations of The Nasdaq Stock Market LLC. The Sarbanes-Oxley Act requires, among other things, that we maintain effective disclosure controls and procedures and internal control over financial reporting. We must perform system and process evaluation and testing of our internal control over financial reporting to allow management to report on the effectiveness of our internal controls over financial reporting in our Annual Report on Form 10-K filing for that year, as required by Section 404 of the Sarbanes-Oxley Act.

We may discover weaknesses in our system of internal financial and accounting controls and procedures that could result in a material misstatement of our financial statements. Our internal control over financial reporting will not prevent or detect all errors and all fraud. An internal control system, no matter how well designed and operated, can provide only reasonable, not absolute, assurance that the internal control system’s objectives will be met. Because of the inherent limitations in all internal control systems, no evaluation of internal controls can provide absolute assurance that misstatements due to error or fraud will not occur or that all internal control issues and instances of fraud will be detected.

If we are not able to comply with the requirements of Section 404 of the Sarbanes-Oxley Act, or if we are unable to maintain proper and effective internal controls, we may not be able to produce timely and accurate financial statements. If that were to happen, the market price of our common stock could decline and we could be subject to sanctions or investigations by The Nasdaq Stock Market LLC, the SEC, or other regulatory authorities.

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

Our disclosure controls and procedures are designed to reasonably ensure that information required to be disclosed by us in reports we file or submits under the Exchange Act is accumulated and communicated to management and recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC. We believe that any disclosure controls and procedures as well as internal controls and procedures, no matter how well-conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are and will be met. These inherent limitations include the realities that judgments in decision-making can be faulty and that breakdowns can occur because of simple error or mistake. Additionally, controls can be circumvented by the individual acts of some persons, by collusion of two or more people or by an unauthorized override of the controls. Accordingly, because of the inherent limitations in our control system, misstatements due to error or fraud may occur and not be detected.

We will continue to incur costs and demands upon management as a result of complying with the laws and regulations affecting public companies.

We will incur significant legal, accounting, and other expenses associated with public company reporting requirements. We will also incur costs associated with corporate governance requirements, including requirements under the Sarbanes-Oxley Act, as well as new rules implemented by the SEC and The Nasdaq Stock Market LLC. Although our status as a smaller reporting company may for a limited period of time somewhat lessen the cost of complying with these additional regulatory and other requirements, we nonetheless expect that these rules and regulations will increase our legal and financial compliance costs and to make some activities more time-consuming and costlier. Our executive officers and other personnel will need to devote substantial time to oversee our operations as a public company and compliance with applicable laws and regulations. These rules and regulations may also make it difficult and expensive for us to obtain directors and officer’s liability insurance. As a result, it may be more difficult for us to attract and retain qualified individuals to serve on our board of directors or as executive officers of our company, which may adversely affect investor confidence in us and could cause our business or stock price to suffer.

General Risk Factors

Changes in accounting rules and regulations, or interpretations thereof, could result in unfavorable accounting charges or require us to change our compensation policies.

Accounting methods and policies for biopharmaceutical companies, including policies governing revenue recognition, research and development and related expenses, and accounting for stock-based compensation, are subject to review,

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interpretation, and guidance from our auditors and relevant accounting authorities, including the SEC. Changes to accounting methods or policies, or interpretations thereof, may require us to reclassify, restate, or otherwise change or revise our financial statements.

Environmental, social and governance matters may impact our business and reputation.

Companies are increasingly being judged by their performance on a variety of environmental, social and governance, or ESG, matters, which are considered to contribute to the long-term sustainability of companies’ performance.

A variety of organizations measure the performance of companies on such ESG topics, and the results of these assessments are widely publicized. In addition, investment in funds that specialize in companies that perform well in such assessments are increasingly popular, and major institutional investors have publicly emphasized the importance of such ESG measures to their investment decisions. Topics considered in such assessments include, among others, the role of the company’s board of directors in supervising various ESG issues and board diversity.

In light of investors’ increased focus on ESG matters, there can be no certainty that we will manage such issues successfully, or that we will successfully meet expectations as to our proper role. Any failure or perceived failure by us in this regard could have a material adverse effect on our reputation and on our business, share price, financial condition, or results of operations, including the sustainability of our business over time.

If equity research analysts do not publish research or reports, or publish unfavorable research or reports, about us, our business or our market, our stock price and trading volume could decline.

The trading market for our common stock will be influenced by the research and reports that equity research analysts publish about us and our business. Equity research analysts may elect not to provide research coverage of our common stock or discontinue existing research coverage, and such lack of research coverage may adversely affect the market price of our common stock. We do not have any control over the analysts, or the content and opinions included in their reports. The price of our common stock could decline if one or more equity research analysts downgrade our stock or issue other unfavorable commentary or research. If one or more equity research analysts ceases coverage of us or fails to publish reports regularly, demand for our common stock could decrease, which in turn could cause our stock price or trading volume to decline.

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

On August 17, 2022, we granted an option to purchase 160,000 shares of our common stock with an exercise price of $8.38 per share to Dr. Andrew Sandler, our Chief Medical Officer, as an “inducement” grant pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. One-fourth of the shares underlying the option will vest on August 17, 2023 and 1/48th of the total number of shares underlying the option will vest on each monthly anniversary thereafter, such that the shares underlying the option will be fully vested on August 17, 2026. Vesting of the option is subject to Dr. Sandler’s continued employment with us on the applicable vesting dates. The option’s expiration date is August 16, 2032. The grant of the option was exempt from registration under the Securities Act of 1933, as amended, pursuant to Section 4(a)(2) thereof as a transaction by an issuer not involving a public offering. .

Item 3. Defaults Upon Senior Securities.

None.

Item 4. Mine Safety Disclosures.

Not applicable.

Item 5. Other Information

None.

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Item 6. Exhibits.

Exhibit Number	Exhibit Description	Incorporation by Reference				Filed Herewith
		Form	File No.	Exhibit	Filing Date
10.1+	Form of Stand-Alone Inducement Stock Option Grant between the Company and Andrew Sandler					X
31.1	Certification of Principal Executive Officer Required Under Rule 13a-14(a) and 15d-14(a) of the Securities Exchange Act of 1934, as amended					X
31.2	Certification of Principal Financial Officer Required Under Rule 13a-14(a) and 15d-14(a) of the Securities Exchange Act of 1934, as amended					X
32.1*	Certification of Principal Executive Officer Required Under Rule 13a-14(b) of the Securities Exchange Act of 1934, as amended, and 18 U.S.C. §1350					X
32.2*	Certification of Principal Financial Officer Required Under Rule 13a-14(b) of the Securities Exchange Act of 1934, as amended, and 18 U.S.C. §1350					X
101.INS	Inline XBRL Instance Document					X
101.SCH	Inline XBRL Taxonomy Extension Schema Linkbase Document					X
101.CAL	Inline XBRL Taxonomy Extension Calculation Linkbase Document					X
101.DEF	Inline XBRL Taxonomy Extension Definition Linkbase Document					X
101.LAB	Inline XBRL Taxonomy Extension Label Linkbase Document					X
101.PRE	Inline XBRL Taxonomy Extension Presentation Linkbase Document					X
104	Cover page formatted as Inline XBRL and contained in Exhibit 101

+

Indicates a management contract or a compensatory plan, contract or arrangement.

*

The certifications attached as Exhibits 32.1 and 32.2 that accompany this Quarterly Report on Form 10-Q are not deemed filed with the Securities and Exchange Commission and are not to be incorporated by reference into any filing of Alpine Immune Sciences, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, whether made before or after the date of this Form 10-Q, irrespective of any general incorporation language contained in such filing.

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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.

		ALPINE IMMUNE SCIENCES, INC.
Date:	November 14, 2022	By:	/s/ Mitchell H. Gold, M.D.
		Name:	Mitchell H. Gold, M.D.
		Title:	Executive Chairman and Chief Executive Officer

		ALPINE IMMUNE SCIENCES, INC.
Date:	November 14, 2022	By:	/s/ Paul Rickey
		Name:	Paul Rickey
		Title:	Senior Vice President and Chief Financial Officer

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EX-10.1

Exhibit 10.1

ALPINE IMMUNE SCIENCES, INC.

STAND-ALONE INDUCEMENT STOCK OPTION GRANT

NOTICE OF GRANT OF STOCK OPTION

This grant (the “Option”) shall be governed by this Notice of Grant of Stock Option (the “Notice of Grant”) and the Terms and Conditions of Stock Option Grant (the “Terms and Conditions”), attached hereto as Exhibit A (together, the “Agreement”). Terms not otherwise defined in the Notice of Grant shall be defined in the Terms and Conditions of Stock Option Grant.

Participant:	Andrew Sandler
Address:	1812 10th Ave East
	Seattle, WA 98102

Participant has been granted an Option to purchase Common Stock of the Company, subject to the terms and conditions of this Agreement, as follows:

Date of Grant	August 17, 2022
Vesting Commencement Date	August 17, 2022
Number of Shares Granted	160,000
Exercise Price per Share	$8.38
Total Exercise Price	$1,340,800.00
Type of Option	Nonstatutory Stock Option
Term/Expiration Date	August 16, 2032

Vesting Schedule:

Subject to accelerated vesting as set forth in the Company’s Change of Control and Severance Policy or in the Agreement, this Option will be exercisable, in whole or in part, in accordance with the following schedule:

Twenty-five percent (25%) of the Shares subject to the Option will vest on the one (1) year anniversary of the Vesting Commencement Date, and one forty-eighth (1/48th) of the Shares subject to the Option will vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month), subject to Participant continuing to be a Service Provider through each such date.

- 1 -

Termination Period:

This Option will be exercisable for three (3) months after Participant ceases to be a Service Provider, unless such termination is due to Participant’s death or Disability, in which case this Option will be exercisable for twelve (12) months after Participant ceases to be a Service Provider. Notwithstanding the foregoing sentence, in no event may this Option be exercised after the Term/Expiration Date as provided above and may be subject to earlier termination as provided in Section 14(c) of the Terms and Conditions.

By Participant’s signature and the signature of the Company’s representative below, Participant and the Company agree that this Option is granted under and governed by the terms and conditions of this Agreement. Participant has reviewed this Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Agreement and fully understands all provisions of the Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions relating to the Agreement. Participant further agrees to notify the Company upon any change in the residence address indicated below.

PARTICIPANT	ALPINE IMMUNE SCIENCES, INC.
/s/Andrew Sandler	/s/Paul Rickey
Signature	By
Andrew Sandler	Paul Rickey, Chief Financial Officer
Print Name	Title

[signature page of the A. Sandler Notice of Grant of Stock Option]

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EXHIBIT A

TERMS AND CONDITIONS OF STOCK OPTION GRANT

1.Definitions. As used herein, the following definitions shall apply:

(a)“Administrator” means the Committee as will have administrative authority under this Agreement, in accordance with Section 4 of the Terms and Conditions.

(b)“Applicable Laws” means the legal and regulatory requirements relating to the administration of equity-based awards under U.S. state corporate laws, U.S. federal and state securities laws, the Code, any stock exchange or quotation system on which the Common Stock is listed or quoted and the applicable laws of any foreign country or jurisdiction that may apply to this Option.

(c)“Board” means the Board of Directors of the Company.

(d)“Change in Control” means the occurrence of any of the following events:

(i)Change in Ownership of the Company. A change in the ownership of the Companywhich occurs on the date that any one person, or more than one person acting as a group (“Person”), acquires ownership of the stock of the Company that, together with the stock held by such Person, constitutes more than fifty percent (50%) of the total voting power of the stock of the Company; provided, however, that for purposes of this subsection, (A) the acquisition of additional stock by any one Person, who is considered to own more than fifty percent (50%) of the total voting power of the stock of the Company will not be considered a Change in Control and (B) if the stockholders of the Company immediately before such change in ownership continue to retain immediately after the change in ownership, in substantially the same proportions as their ownership of shares of the Company’s voting stock immediately prior to the change in ownership, the direct or indirect beneficial ownership of fifty percent (50%) or more of the total voting power of the stock of the Company or of the ultimate parent entity of the Company, such event shall not be considered a Change in Control under this subsection (i). For this purpose, indirect beneficial ownership shall include, without limitation, an interest resulting from ownership of the voting securities of one or more corporations or other business entities which own the Company, as the case may be, either directly or through one or more subsidiary corporations or other business entities; or

(ii)Change in Effective Control of the Company. A change in the effective control of the Company which occurs on the date that a majority of members of the Board is replaced during any twelve (12) month period by Directors whose appointment or election is not endorsed by a majority of the members of the Board prior to the date of the appointment or election. For purposes of this subsection (ii), if any Person is considered to be in effective control of the Company, the acquisition of additional control of the Company by the same Person will not be considered a Change in Control; or

(iii)Change in Ownership of a Substantial Portion of the Company’s Assets. A change in the ownership of a substantial portion of the Company’s assets which occurs on the date that any Person acquires (or has acquired during the twelve (12) month period ending on the date of the most recent acquisition by such person or persons) assets from the Company that have a total gross fair market value equal to or more than fifty percent (50%) of the total gross fair market

    -3-

value of all of the assets of the Company immediately prior to such acquisition or acquisitions; provided, however, that for purposes of this subsection (iii), the following will not constitute a change in the ownership of a substantial portion of the Company’s assets: (A) a transfer to an entity that is controlled by the Company’s stockholders immediately after the transfer, or (B) a transfer of assets by the Company to: (1) a stockholder of the Company (immediately before the asset transfer) in exchange for or with respect to the Company’s stock, (2) an entity, fifty percent (50%) or more of the total value or voting power of which is owned, directly or indirectly, by the Company, (3) a Person, that owns, directly or indirectly, fifty percent (50%) or more of the total value or voting power of all the outstanding stock of the Company, or (4) an entity, at least fifty percent (50%) of the total value or voting power of which is owned, directly or indirectly, by a Person described in this subsection (iii)(B)(3). For purposes of this subsection (iii), gross fair market value means the value of the assets of the Company, or the value of the assets being disposed of, determined without regard to any liabilities associated with such assets.

For purposes of this definition, persons will be considered to be acting as a group if they are owners of a corporation that enters into a merger, consolidation, purchase or acquisition of stock, or similar business transaction with the Company.

Notwithstanding the foregoing, a transaction shall not be deemed a Change in Control unless the transaction qualifies as a “change in control event” within the meaning of Section 409A of the Code, as it has been and may be amended from time to time, and any proposed or final Treasury Regulations and Internal Revenue Service guidance that has been promulgated or may be promulgated thereunder from time to time.

Further and for the avoidance of doubt, a transaction shall not constitute a Change in Control if: (i) its sole purpose is to change the jurisdiction of the Company’s incorporation, or (ii) its sole purpose is to create a holding company that shall be owned in substantially the same proportions by the persons who held the Company’s securities immediately before such transaction.

(e) “Code” means the Internal Revenue Code of 1986, as amended. Reference to a specific section of the Code or Treasury Regulation thereunder will include such section or regulation, any valid regulation or other official applicable guidance promulgated under such section, and any comparable provision of any future legislation or regulation amending, supplementing or superseding such section or regulation.

(f)“Committee” means the Compensation Committee of the Board.

(g)“Common Stock” means the common stock of the Company.

(h)“Company” means Alpine Immune Sciences, Inc., a Delaware corporation, or any successor thereto.

(i)“Consultant” means any natural person, including an advisor, engaged by the Company or a Parent or Subsidiary to render bona fide services to such entity, provided the services (i) are not in connection with the offer or sale of securities in a capital-raising transaction, and (ii) do not directly promote or maintain a market for the Company’s securities, in each case, within the meaning of Form S-8 promulgated under the Securities Act, and provided further, that a Consultant

    -4-

will include only those persons to whom the issuance of Shares may be registered under Form S-8 promulgated under the Securities Act.

(j)“Director” means a member of the Board.

(k)“Disability” means total and permanent disability as defined in Section 22(e)(3) of the Code, provided that the Administrator in its discretion may determine whether a permanent and total disability exists in accordance with uniform and non-discriminatory standards adopted by the Administrator from time to time.

(l)“Employee” means any person, including Officers and Directors, employed by the Company or any Parent or Subsidiary of the Company. Neither service as a Director nor payment of a director’s fee by the Company will be sufficient to constitute “employment” by the Company.

(m)“Exchange Act” means the Securities Exchange Act of 1934, as amended.

(n)“Exchange Program” means a program under which (i) the Option is surrendered or cancelled in exchange another stock option (which may have higher or lower exercise prices and different terms), equity awards of a different type, and/or cash, (ii) Participant would have the opportunity to transfer for value the Option to a financial institution or other person or entity selected by the Administrator, and/or (iii) the exercise price of the Option is reduced or increased. The Administrator will determine the terms and conditions of any Exchange Program in its sole discretion.

(o)“Fair Market Value” means, as of any date, the value of Common Stock determined as follows:

(i)If the Common Stock is listed on any established stock exchange or a national market system, including without limitation the Nasdaq Global Market, the Nasdaq Global Select Market or the Nasdaq Capital Market, its Fair Market Value shall be the closing sales price for such stock (or, if no closing sales price was reported on that date, as applicable, on the last trading date such closing sales price is reported) as quoted on such exchange or system on the day of determination, as reported in The Wall Street Journal or such other source as the Administrator deems reliable;

(ii)If the Common Stock is regularly quoted by a recognized securities dealer but selling prices are not reported, its Fair Market Value shall be the mean between the high bid and low asked prices for the Common Stock on the day of determination (or, if no bids and asks were reported on that date, as applicable, on the last trading date such bids and asks are reported); or

(iii)In the absence of an established market for the Common Stock, the Fair Market Value will be determined in good faith by the Administrator.

(p)“Incentive Stock Option” means an Option that by its terms qualifies and is otherwise intended to qualify as an incentive stock option within the meaning of Section 422 of the Code and the regulations promulgated thereunder.

(q)“Nonstatutory Stock Option” means an Option that by its terms does not qualify or is not intended to qualify as an Incentive Stock Option.

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(r)“Officer” means a person who is an officer of the Company within the meaning of Section 16 of the Exchange Act and the rules and regulations promulgated thereunder.

(s)“Option” means the stock option set forth in the Notice of Grant.

(t)“Outside Director” means a Director who is not an Employee.

(u)“Parent” means a “parent corporation,” whether now or hereafter existing, as defined in Section 424(e) of the Code.

(v)“Participant” means the holder of the Option.

(w)“Service Provider” means an Employee, Director or Consultant.

(x)“Share” means a share of the Common Stock, as adjusted in accordance with Section 14(a) of the Terms and Conditions.

(y)“Subsidiary” means a “subsidiary corporation”, whether now or hereafter existing, as defined in Section 424(f) of the Code.

2.Grant of Option. The Company hereby grants to the Participant named in the Notice of Grant the Option to purchase the number of Shares, as set forth in the Notice of Grant, at the exercise price per Share set forth in the Notice of Grant (the “Exercise Price”), subject to all of the terms and conditions in this Agreement.

This Option is intended to qualify as an employment inducement award under NASDAQ Listing Rule 5635(c)(4) (the “Inducement Listing Rule”). Accordingly, (i) Participant was not previously an Employee or Director, or the Participant is returning to employment of the Company following a bona-fide period of non-employment; and (ii) the grant of the Option is an inducement material to the Participant’s entering into employment with the Company in accordance with the Inducement Listing Rule.

3.Vesting Schedule. The Option awarded by this Agreement will vest in accordance with the vesting provisions set forth in the Notice of Grant. Shares scheduled to vest on a certain date or upon the occurrence of a certain condition will not vest in Participant in accordance with any of the provisions of this Agreement, unless Participant will have been continuously a Service Provider from the Date of Grant until the date such vesting occurs.

4.Authority of the Administrator.

(a)Powers of the Administrator. Subject to the provisions of this Agreement, the Administrator will have the authority, in its discretion:

(i)to determine the terms and conditions of any, and to institute any Exchange Program;

(ii)to construe and interpret the terms of the Agreement and the Option;

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(iii)to prescribe, amend and rescind rules and regulations relating to the Agreement, including rules and regulations relating to sub-plans established for the purpose of satisfying applicable foreign laws or for qualifying for favorable tax treatment under applicable foreign laws;

(iv)to modify or amend the Option (subject to Section 21 of the Terms and Conditions), including but not limited to the discretionary authority to extend the post-termination exercisability period of the Option and to extend the maximum term of the Option;

(v)to allow Participant to satisfy withholding tax obligations in such manner as prescribed in Section 7 of the Terms and Conditions;

(vi)to allow a Participant to defer the receipt of the payment of cash or the delivery of Shares that would otherwise be due to such Participant under the Option pursuant to such procedures as the Administrator may determine; and

(vii)to make all other determinations deemed necessary or advisable for administering the Agreement.

(b)Effect of Administrator’s Decision. The Administrator’s decisions, determinations and interpretations will be final and binding on the Participant and any other holders of Shares subject to the Option.

(c)No Liability. Under no circumstances shall the Company, its Affiliates, the Administrator, or the Board incur liability for any indirect, incidental, consequential or special damages (including lost profits) of any form incurred by any person, whether or not foreseeable and regardless of the form of the act in which such a claim may be brought, with respect to the Agreement or the Company’s, its Affiliates’, the Administrator’s or the Board’s roles in connection with the Agreement.

5.Exercise of Option.

(a)Right to Exercise. This Option may be exercised only within the term set out in the Notice of Grant, and may be exercised during such term only in accordance with the terms of this Agreement.

(b)Method of Exercise. This Option is exercisable by delivery of an exercise notice, in the form attached as Exhibit B (the “Exercise Notice”) or in a manner and pursuant to such procedures as the Administrator may determine, which will state the election to exercise the Option, the number of Shares in respect of which the Option is being exercised (the “Exercised Shares”), and such other representations and agreements as may be required by the Company pursuant to the provisions of the Agreement. The Exercise Notice will be completed by Participant and delivered to the Company. The Exercise Notice will be accompanied by payment of the aggregate Exercise Price as to all Exercised Shares together with any applicable tax withholding. This Option will be deemed to be exercised upon receipt by the Company of such fully executed Exercise Notice accompanied by the aggregate Exercise Price.

    -7-

(c)Termination of Relationship as a Service Provider. If a Participant ceases to be a Service Provider, the Participant may exercise his or her Option within such period of time as is specified in the Notice of Grant to the extent that the Option is vested on the date of termination (but in no event later than the expiration of the term of such Option as set forth in the Notice of Grant). Unless otherwise provided by the Administrator, if on the date of termination the Participant is not vested as to his or her entire Option, the Shares covered by the unvested portion of the Option will forfeit. If after termination the Participant does not exercise his or her Option within the time specified by the Administrator, the Option will terminate, and the Shares covered by such Option will forfeit.

6.Method of Payment. Payment of the aggregate Exercise Price will be by any of the following, or a combination thereof, at the election of Participant:

(a)cash;

(b)check;

(c)consideration received by the Company under a formal cashless exercise program adopted by the Company in connection with the Agreement; or

(d)surrender of other Shares which have a Fair Market Value on the date of surrender equal to the aggregate Exercise Price of the Exercised Shares, provided that accepting such Shares, in the sole discretion of the Administrator, will not result in any adverse accounting consequences to the Company.

7.Tax Obligations.

(a)Withholding of Taxes. Notwithstanding any contrary provision of this Agreement, no certificate representing the Shares will be issued to Participant, unless and until satisfactory arrangements (as determined by the Administrator) will have been made by Participant with respect to the payment of income, employment and other taxes which the Company determines must be withheld with respect to such Shares. To the extent determined appropriate by the Company in its discretion, it will have the right (but not the obligation) to satisfy any tax withholding obligations by reducing the number of Shares otherwise deliverable to Participant. If Participant fails to make satisfactory arrangements for the payment of any required tax withholding obligations hereunder at the time of the Option exercise, Participant acknowledges and agrees that the Company may refuse to honor the exercise and refuse to deliver the Shares if such withholding amounts are not delivered at the time of exercise.

(b)Code Section 409A. Under Code Section 409A, an option that vests after December 31, 2004 (or that vested on or prior to such date but which was materially modified after October 3, 2004) that was granted with a per Share exercise price that is determined by the Internal Revenue Service (the “IRS”) to be less than the Fair Market Value of a Share on the date of grant (a “Discount Option”) may be considered “deferred compensation.” A Discount Option may result in (i) income recognition by Participant prior to the exercise of the option, (ii) an additional twenty percent (20%) federal income tax, and (iii) potential penalty and interest charges. The Discount Option may also result in additional state income, penalty and interest charges to the Participant. Participant acknowledges that the Company cannot and has not guaranteed that the IRS will agree that the per Share exercise price of this Option equals or exceeds the Fair Market Value of a Share on the Date of

    -8-

Grant in a later examination. Participant agrees that if the IRS determines that the Option was granted with a per Share exercise price that was less than the Fair Market Value of a Share on the date of grant, Participant will be solely responsible for Participant’s costs related to such a determination.

8.Rights as Stockholder. Neither Participant nor any person claiming under or through Participant will have any of the rights or privileges of a stockholder of the Company in respect of any Shares deliverable hereunder unless and until certificates representing such Shares will have been issued, recorded on the records of the Company or its transfer agents or registrars, and delivered to Participant. After such issuance, recordation and delivery, Participant will have all the rights of a stockholder of the Company with respect to voting such Shares and receipt of dividends and distributions on such Shares.

9.Compliance With Code Section 409A. The Option will be designed and operated in such a manner that it is either exempt from the application of, or comply with, the requirements of Code Section 409A such that the grant, payment, settlement or deferral will not be subject to the additional tax or interest applicable under Code Section 409A, except as otherwise determined in the sole discretion of the Administrator. The Agreement is intended to meet the requirements of Code Section 409A and will be construed and interpreted in accordance with such intent, except as otherwise determined in the sole discretion of the Administrator. To the extent that the Option or payment, or the settlement or deferral thereof, is subject to Code Section 409A the Option will be granted, paid, settled or deferred in a manner that will meet the requirements of Code Section 409A, such that the grant, payment, settlement or deferral will not be subject to the additional tax or interest applicable under Code Section 409A.

10.Leaves of Absence/Transfer Between Locations. Unless the Administrator provides otherwise and except as required by Applicable Laws, vesting of the Option granted hereunder will be suspended during any unpaid leave of absence. A Participant will not cease to be an Employee in the case of (i) any leave of absence approved by the Company or (ii) transfers between locations of the Company or between the Company, its Parent, or any Subsidiary.

11.No Guarantee of Continued Service. PARTICIPANT ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED ONLY BY CONTINUING AS A SERVICE PROVIDER AT THE WILL OF THE COMPANY (OR THE PARENT OR SUBSIDIARY EMPLOYING OR RETAINING PARTICIPANT) AND NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR ACQUIRING SHARES HEREUNDER. PARTICIPANT FURTHER ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE TRANSACTIONS CONTEMPLATED HEREUNDER AND THE VESTING SCHEDULE SET FORTH HEREIN DO NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A SERVICE PROVIDER FOR THE VESTING PERIOD, FOR ANY PERIOD, OR AT ALL, AND WILL NOT INTERFERE IN ANY WAY WITH PARTICIPANT’S RIGHT OR THE RIGHT OF THE COMPANY (OR THE PARENT OR SUBSIDIARY EMPLOYING OR RETAINING PARTICIPANT) TO TERMINATE PARTICIPANT’S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR WITHOUT CAUSE.

12.Address for Notices. Any notice to be given to the Company under the terms of this Agreement will be addressed to the Company at Alpine Immune Sciences, Inc., 201 Elliott Avenue

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West, Suite 230, Seattle, WA 98119, or at such other address as the Company may hereafter designate in writing.

13.Non-Transferability of Option. Unless otherwise determined by the Administrator, this Option may not be transferred in any manner otherwise than by will or by the laws of descent or distribution and may be exercised during the lifetime of Participant only by Participant. If the Administrator makes the Option transferable, such Option will contain such additional terms and conditions as the Administrator deems appropriate.

14.Adjustments; Dissolution or Liquidation; Merger or Change in Control.

(a)Adjustments. In the event that any dividend or other distribution (whether in the form of cash, Shares, other securities, or other property), recapitalization, stock split, reverse stock split, reorganization, merger, consolidation, split-up, spin-off, combination, repurchase, or exchange of Shares or other securities of the Company, or other change in the corporate structure of the Company affecting the Shares occurs, the Administrator, in order to prevent diminution or enlargement of the benefits or potential benefits intended to be made available under the Agreement, will adjust the number, class, and price of Shares covered by the Option.

(b)Dissolution or Liquidation. In the event of the proposed dissolution or liquidation of the Company, the Administrator will notify each Participant as soon as practicable prior to the effective date of such proposed transaction. To the extent it has not been previously exercised, the Option will terminate immediately prior to the consummation of such proposed action.

(c)Change in Control. In the event of a merger or Change in Control, the Option will be treated as the Administrator determines, including, without limitation that the Option be assumed or an equivalent option or right substituted by the successor corporation or a Parent or Subsidiary of the successor corporation.

In the event that the successor corporation does not assume or substitute for the Option (or portion thereof), the Participant will fully vest in and have the right to exercise all of his or her outstanding Options that are not assumed or substituted for, including Shares as to which the Option would not otherwise be vested or exercisable. In addition, if the Option is not assumed or substituted for in the event of a Change in Control, the Administrator will notify the Participant in writing or electronically that the Option will be fully vested and exercisable for a period of time determined by the Administrator in its sole discretion, and the Option will terminate upon the expiration of such period.

For the purposes of this subsection 14(c), the Option will be considered assumed if, following the merger or Change in Control, the Option confers the right to purchase or receive, for each Share subject to the Option immediately prior to the merger or Change in Control, the consideration (whether stock, cash, or other securities or property) received in the merger or Change in Control by holders of Common Stock for each Share held on the effective date of the transaction (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of the outstanding Shares); provided, however, that if such consideration received in the merger or Change in Control is not solely common stock of the successor corporation or its Parent, the Board may, with the consent of the successor corporation, provide for the consideration to be received upon the exercise of the Option, for each Share subject to the Option, to be solely common stock of the successor

    -10-

corporation or its Parent equal in fair market value to the per share consideration received by holders of Common Stock in the merger or Change in Control.

Notwithstanding anything in this subsection (c) to the contrary, if a payment under the Agreement is subject to Section 409A of the Code and if the Change in Control definition contained in the Agreement does not comply with the definition of “change in control” for purposes of a distribution under Section 409A of the Code, then any payment of an amount that is otherwise accelerated under this Section will be delayed until the earliest time that such payment would be permissible under Section 409A of the Code without triggering any penalties applicable under Section 409A of the Code.

15.Date of Grant. The date of grant of the Option will be, for all purposes, the date on which the Administrator makes the determination granting the Option, or such other later date as is determined by the Administrator. Notice of the determination will be provided to each Participant within a reasonable time after the date of such grant.

16.Binding Agreement. Subject to the limitation on the transferability of this grant contained herein, this Agreement will be binding upon and inure to the benefit of the heirs, legatees, legal representatives, successors and assigns of the parties hereto.

17.Additional Conditions to Issuance of Stock. If at any time the Company will determine, in its discretion, that the listing, registration or qualification of the Shares upon any securities exchange or under any state or federal law, or the consent or approval of any governmental regulatory authority is necessary or desirable as a condition to the issuance of Shares to Participant (or his or her estate), such issuance will not occur unless and until such listing, registration, qualification, consent or approval will have been effected or obtained free of any conditions not acceptable to the Company. The Company will make all reasonable efforts to meet the requirements of any such state or federal law or securities exchange and to obtain any such consent or approval of any such governmental authority. Assuming such compliance, for income tax purposes the Exercised Shares will be considered transferred to Participant on the date the Option is exercised with respect to such Exercised Shares.

18.Electronic Delivery. The Company may, in its sole discretion, decide to deliver any documents related to Options awarded under the Agreement or future options that may be awarded under the Agreement by electronic means or request Participant’s consent to participate by electronic means. Participant hereby consents to receive such documents by electronic delivery and agrees to participate through any on-line or electronic system established and maintained by the Company or another third party designated by the Company.

19.Captions. Captions provided herein are for convenience only and are not to serve as a basis for interpretation or construction of this Agreement.

20.Agreement Severable. In the event that any provision in this Agreement will be held invalid or unenforceable, such provision will be severable from, and such invalidity or unenforceability will not be construed to have any effect on, the remaining provisions of this Agreement.

21.Entire Agreement. This Agreement constitutes the entire agreement of the parties with respect to the subject matter hereof and supersedes in their entirety all prior undertakings and

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agreements of the Company and Participant with respect to the subject matter hereof, and may not be modified adversely to Participant’s interest except by means of a writing signed by the Company and Participant. Notwithstanding anything to the contrary in this Agreement, the Company reserves the right to revise this Agreement as it deems necessary or advisable, in its sole discretion and without the consent of Participant, to comply with Code Section 409A or to otherwise avoid imposition of any additional tax or income recognition under Section 409A of the Code in connection to this Option.

22.Acknowledgment. By accepting this Option, Participant expressly warrants that he or she has received an Option pursuant to this Agreement, and has received, read and understood a description of the Agreement.

23.Governing Law. This Agreement will be governed by the laws of the State of Washington, without giving effect to the conflict of law principles thereof. For purposes of litigating any dispute that arises under this Option or this Agreement, the parties hereby submit to and consent to the jurisdiction of the State of Washington, and agree that such litigation will be conducted in the state courts of Washington in King County, or the federal courts for the United States for the Western District of Washington, and no other courts, where this Option is made and/or to be performed.

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EXHIBIT B

ALPINE IMMUNE SCIENCES, INC.

STAND-ALONE INDUCEMENT STOCK OPTION GRANT

EXERCISE NOTICE

Alpine Immune Sciences, Inc.

188 East Blaine Street, Suite 200

Seattle, WA 98102

Attention: Stock Administration

1.Exercise of Option. Effective as of today, ________________, _____, the undersigned (“Purchaser”) hereby elects to purchase ______________ shares (the “Shares”) of the Common Stock of Alpine Immune Sciences, Inc. (the “Company”), under and pursuant to the Stand-Alone Inducement Stock Option Grant, including the Notice of Grant, the Terms and Conditions of Stock Option Grant, and exhibits attached thereto (the “Agreement”). The purchase price for the Shares will be $_____________, as required by the Agreement.

2.Delivery of Payment. Purchaser herewith delivers to the Company the full purchase price of the Shares and any tax obligations (as set forth in Section 7 of the Terms and Conditions) to be paid in connection with the exercise of the Option.

3.Representations of Purchaser. Purchaser acknowledges that Purchaser has received, read and understood the Plan and the Option Agreement and agrees to abide by and be bound by their terms and conditions.

4.Rights as Stockholder. Until the issuance (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company) of the Shares, no right to vote or receive dividends or any other rights as a stockholder will exist with respect to the Shares subject to the Option, notwithstanding the exercise of the Option. The Shares so acquired will be issued to Purchaser as soon as practicable after exercise of the Option. No adjustment will be made for a dividend or other right for which the record date is prior to the date of issuance, except as provided in Section 14 of the Terms and Conditions.

5.Tax Consultation. Purchaser understands that Purchaser may suffer adverse tax consequences as a result of Purchaser’s purchase or disposition of the Shares. Purchaser represents that Purchaser has consulted with any tax consultants Purchaser deems advisable in connection with the purchase or disposition of the Shares and that Purchaser is not relying on the Company for any tax advice.

6.Entire Agreement; Governing Law. The Option Agreement is incorporated herein by reference. This Exercise Notice and the Option Agreement constitute the entire agreement of the parties

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with respect to the subject matter hereof and supersede in their entirety all prior undertakings and agreements of the Company and Purchaser with respect to the subject matter hereof, and may not be modified adversely to the Purchaser’s interest except by means of a writing signed by the Company and Purchaser. This Option Agreement is governed by the internal substantive laws, but not the choice of law rules, of Washington.

Submitted by:	Accepted by:
PURCHASER	ALPINE IMMUNE SCIENCES, INC.
Signature	Signature
Print Name	Print Name
Address:
	Title
	Date Received

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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, Mitchell H. Gold, M.D., certify that:

1.    I have reviewed this Quarterly Report on Form 10-Q of Alpine Immune Sciences, 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: November 14, 2022

/s/ Mitchell H. Gold, M.D.

Mitchell H. Gold, M.D.

Executive Chairman and Chief Executive Officer
(Principal Executive Officer)

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, Paul Rickey, certify that:

1.    I have reviewed this Quarterly Report on Form 10-Q of Alpine Immune Sciences, 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: November 14, 2022

/s/ Paul Rickey

Paul Rickey

Senior Vice President and Chief Financial Officer
(Principal Accounting Officer and Principal Financial Officer)

EX-32.1

Exhibit 32.1

ALPINE IMMUNE SCIENCES, INC.

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 Alpine Immune Sciences, Inc. (the “Company”) on Form 10-Q for the quarter ended September 30, 2022, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Mitchell H. Gold, M.D., Executive Chairman and Chief Executive Officer (Principal Executive Officer) of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(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 results of operations of the Company.

/s/ Mitchell H. Gold, M.D.

Mitchell H. Gold, M.D.

Executive Chairman and Chief Executive Officer
(Principal Executive Officer)

November 14, 2022

A signed original of this written statement required by Section 906 of the Sarbanes-Oxley Act of 2002 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.

This certification accompanies the Report to which it relates, is not deemed filed with the Securities and Exchange Commission and is not to be incorporated by reference into any filing of Alpine Immune Sciences, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended (whether made before or after the date of the Report), irrespective of any general incorporation language contained in such filing.

EX-32.2

Exhibit 32.2

ALPINE IMMUNE SCIENCES, INC.

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 Alpine Immune Sciences, Inc. (the “Company”) on Form 10-Q for the quarter ended September 30, 2022, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Paul Rickey, Senior Vice President and Chief Financial Officer (Principal Accounting Officer and Principal Financial Officer) of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(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 results of operations of the Company.

/s/ Paul Rickey

Paul Rickey

Senior Vice President and Chief Financial Officer

(Principal Accounting Officer and Principal Financial Officer)

November 14, 2022

A signed original of this written statement required by Section 906 of the Sarbanes-Oxley Act of 2002 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.

This certification accompanies the Report to which it relates, is not deemed filed with the Securities and Exchange Commission and is not to be incorporated by reference into any filing of Alpine Immune Sciences, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended (whether made before or after the date of the Report), irrespective of any general incorporation language contained in such filing.

XML

Cover - shares	9 Months Ended
	Sep. 30, 2022	Nov. 08, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	001-37449
Entity Registrant Name	ALPINE IMMUNE SCIENCES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8969493
Entity Address, Address Line One	188 East Blaine Street, Suite 200
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98102
City Area Code	206
Local Phone Number	788-4545
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	ALPN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		45,914,433
Entity Central Index Key	0001626199
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false

XML

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 126,625	$ 67,907
Short-term investments	122,237	94,396
Accounts receivable	382	25,000
Prepaid expenses and other current assets	3,995	4,710
Total current assets	253,239	192,013
Restricted cash, noncurrent	254	254
Property and equipment, net	1,608	1,716
Operating lease, right-of-use asset	8,381	8,837
Long-term investments	28,016	52,866
Deferred tax asset	101	214
Total assets	291,599	255,900
Current liabilities:
Accounts payable	3,240	3,349
Accrued liabilities	13,744	9,417
Deferred revenue, current	46,210	51,773
Operating lease liability, current	718	617
Current portion of long-term debt	4,547	4,622
Total current liabilities	68,459	69,778
Deferred revenue, noncurrent	30,803	50,830
Operating lease liability, noncurrent	10,328	11,009
Long-term debt	0	3,380
Total liabilities	109,590	134,997
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized at September 30, 2022 and December 31, 2021; zero shares issued and outstanding at September 30, 2022 and December 31, 2021	0	0
Common stock, $0.001 par value per share; 200,000,000 shares authorized at September 30, 2022 and December 31, 2021; 45,261,618 shares issued and 44,011,151 shares outstanding at September 30, 2022; 31,444,746 shares issued and 30,194,279 shares outstanding at December 31, 2021	44	30
Treasury stock, at cost; 1,250,467 shares at September 30, 2022 and December 31, 2021	0	0
Additional paid-in capital	388,731	287,345
Accumulated other comprehensive loss	(1,669)	(273)
Accumulated deficit	(205,097)	(166,199)
Total stockholders’ equity	182,009	120,903
Total liabilities and stockholders’ equity	$ 291,599	$ 255,900

XML

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	0	0
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	45,261,618	31,444,746
Common stock, shares outstanding (in shares)	44,011,151	30,194,279
Treasury stock, shares (in shares)	1,250,467	1,250,467

XML

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Collaboration revenue	$ 8,367	$ 8,516	$ 27,288	$ 18,913
Operating expenses:
Research and development	17,589	18,309	51,487	43,380
General and administrative	4,610	3,470	13,579	10,016
Total operating expenses	22,199	21,779	65,066	53,396
Loss from operations	(13,832)	(13,263)	(37,778)	(34,483)
Other income (expense):
Interest expense	(105)	(203)	(389)	(638)
Interest income	664	52	1,123	166
Other expense	0	0	(72)	0
Loss before taxes	(13,273)	(13,414)	(37,116)	(34,955)
Income tax expense	0	(80)	(1,782)	(211)
Net loss	(13,273)	(13,494)	(38,898)	(35,166)
Comprehensive income (loss):
Unrealized loss on investments	(307)	(17)	(1,385)	(1)
Unrealized gain (loss) on foreign currency translation	7	(13)	(11)	(37)
Comprehensive loss	$ (13,573)	$ (13,524)	$ (40,294)	$ (35,204)
Weighted-average shares used to compute basic net loss per share (in shares)	31,574,358	24,724,442	31,559,886	24,169,993
Weighted-average shares used to compute diluted net loss per share (in shares)	31,574,358	24,724,442	31,559,886	24,169,993
Basic net loss per share (in dollars per share)	$ (0.42)	$ (0.55)	$ (1.23)	$ (1.45)
Diluted net loss per share (in dollars per share)	$ (0.42)	$ (0.55)	$ (1.23)	$ (1.45)
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	Collaboration [Member]	Collaboration [Member]	Collaboration [Member]	Collaboration [Member]

XML

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Treasury	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance, common stock (in shares) at Dec. 31, 2020		23,803,183
Beginning balance at Dec. 31, 2020	$ 62,158	$ 24	$ 0	$ 177,947	$ 53	$ (115,866)
Beginning balance, treasury stock (in shares) at Mar. 31, 2021			50,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	1,597			1,597
Issuance of common stock under equity incentive plans (in shares)		78,955
Issuance of common stock under equity incentive plans	202			202
Unrealized gain (loss) on investments	(5)				(5)
Unrealized gain (loss) on foreign currency translation	(15)				(15)
Net loss	(10,643)					(10,643)
Ending balance, common stock (in shares) at Mar. 31, 2021		23,882,138
Ending balance at Mar. 31, 2021	53,294	$ 24	$ 0	179,746	33	(126,509)
Ending balance, treasury stock (in shares) at Dec. 31, 2020			50,467
Beginning balance, common stock (in shares) at Dec. 31, 2020		23,803,183
Beginning balance at Dec. 31, 2020	62,158	$ 24	$ 0	177,947	53	(115,866)
Beginning balance, treasury stock (in shares) at Sep. 30, 2021			1,250,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on investments	(1)
Unrealized gain (loss) on foreign currency translation	(37)
Net loss	(35,166)
Ending balance, common stock (in shares) at Sep. 30, 2021		29,217,692
Ending balance at Sep. 30, 2021	122,825	$ 29	$ 0	273,813	15	(151,032)
Ending balance, treasury stock (in shares) at Dec. 31, 2020			50,467
Beginning balance, common stock (in shares) at Mar. 31, 2021		23,882,138
Beginning balance at Mar. 31, 2021	53,294	$ 24	$ 0	179,746	33	(126,509)
Beginning balance, treasury stock (in shares) at Jun. 30, 2021			50,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	1,545			1,545
Issuance of common stock under equity incentive plans (in shares)		32,741
Issuance of common stock under equity incentive plans	9			9
Unrealized gain (loss) on investments	21				21
Unrealized gain (loss) on foreign currency translation	(9)				(9)
Net loss	(11,029)					(11,029)
Ending balance, common stock (in shares) at Jun. 30, 2021		23,914,879
Ending balance at Jun. 30, 2021	43,831	$ 24	$ 0	181,300	45	(137,538)
Ending balance, treasury stock (in shares) at Mar. 31, 2021			50,467
Beginning balance, treasury stock (in shares) at Sep. 30, 2021			1,250,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in public offering/Private Placement, net of financing costs/offering costs (in shares)		6,489,357
Issuance of common stock in public offering/Private Placement, net of financing costs/offering costs	90,811	$ 6		90,805
Exchange of common stock for prefunded warrants (in shares)		(1,200,000)	1,200,000
Exchange of common stock for prefunded warrants	0	$ (1)		1
Stock-based compensation	1,638			1,638
Issuance of common stock under equity incentive plans (in shares)		13,456
Issuance of common stock under equity incentive plans	69			69
Unrealized gain (loss) on investments	(17)				(17)
Unrealized gain (loss) on foreign currency translation	(13)				(13)
Net loss	(13,494)					(13,494)
Ending balance, common stock (in shares) at Sep. 30, 2021		29,217,692
Ending balance at Sep. 30, 2021	$ 122,825	$ 29	$ 0	273,813	15	(151,032)
Ending balance, treasury stock (in shares) at Jun. 30, 2021			50,467
Beginning balance, common stock (in shares) at Dec. 31, 2021	31,444,746	30,194,279
Beginning balance at Dec. 31, 2021	$ 120,903	$ 30	$ 0	287,345	(273)	(166,199)
Beginning balance, treasury stock (in shares) at Mar. 31, 2022			1,250,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	2,289			2,289
Issuance of common stock under equity incentive plans (in shares)		100,155
Issuance of common stock under equity incentive plans	550			550
Unrealized gain (loss) on investments	(774)				(774)
Unrealized gain (loss) on foreign currency translation	(14)				(14)
Net loss	(7,527)					(7,527)
Ending balance, common stock (in shares) at Mar. 31, 2022		30,294,434
Ending balance at Mar. 31, 2022	$ 115,427	$ 30	$ 0	290,184	(1,061)	(173,726)
Ending balance, treasury stock (in shares) at Dec. 31, 2021	1,250,467		1,250,467
Beginning balance, common stock (in shares) at Dec. 31, 2021	31,444,746	30,194,279
Beginning balance at Dec. 31, 2021	$ 120,903	$ 30	$ 0	287,345	(273)	(166,199)
Beginning balance, treasury stock (in shares) at Sep. 30, 2022	1,250,467		1,250,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in public offering/Private Placement, net of financing costs/offering costs (in shares)		13,606,000
Unrealized gain (loss) on investments	$ (1,385)
Unrealized gain (loss) on foreign currency translation	(11)
Net loss	$ (38,898)
Ending balance, common stock (in shares) at Sep. 30, 2022	45,261,618	44,011,151
Ending balance at Sep. 30, 2022	$ 182,009	$ 44	$ 0	388,731	(1,669)	(205,097)
Ending balance, treasury stock (in shares) at Dec. 31, 2021	1,250,467		1,250,467
Beginning balance, common stock (in shares) at Mar. 31, 2022		30,294,434
Beginning balance at Mar. 31, 2022	$ 115,427	$ 30	$ 0	290,184	(1,061)	(173,726)
Beginning balance, treasury stock (in shares) at Jun. 30, 2022			1,250,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	2,335			2,335
Issuance of common stock under equity incentive plans (in shares)		41,728
Issuance of common stock under equity incentive plans	180			180
Unrealized gain (loss) on investments	(304)				(304)
Unrealized gain (loss) on foreign currency translation	(4)				(4)
Net loss	(18,098)					(18,098)
Ending balance, common stock (in shares) at Jun. 30, 2022		30,336,162
Ending balance at Jun. 30, 2022	$ 99,536	$ 30	$ 0	292,699	(1,369)	(191,824)
Ending balance, treasury stock (in shares) at Mar. 31, 2022			1,250,467
Beginning balance, treasury stock (in shares) at Sep. 30, 2022	1,250,467		1,250,467
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in public offering/Private Placement, net of financing costs/offering costs (in shares)		13,606,000
Issuance of common stock in public offering/Private Placement, net of financing costs/offering costs	$ 93,479	$ 14		93,465
Stock-based compensation	2,555			2,555
Issuance of common stock under equity incentive plans (in shares)		68,989
Issuance of common stock under equity incentive plans	12			12
Unrealized gain (loss) on investments	(307)				(307)
Unrealized gain (loss) on foreign currency translation	7				7
Net loss	$ (13,273)					(13,273)
Ending balance, common stock (in shares) at Sep. 30, 2022	45,261,618	44,011,151
Ending balance at Sep. 30, 2022	$ 182,009	$ 44	$ 0	$ 388,731	$ (1,669)	$ (205,097)
Ending balance, treasury stock (in shares) at Jun. 30, 2022			1,250,467

XML

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net loss	$ (38,898)	$ (35,166)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	7,179	4,780
Amortization of premium/discount on investments	634	602
Depreciation expense	452	482
Non-cash interest expense	145	213
Loss on sale of property and equipment	68	0
Deferred income tax	113	(61)
Changes in operating assets and liabilities:
Accounts receivable	24,618	0
Prepaid expenses and other current assets	858	(1,500)
Operating lease, right-of-use asset	456	421
Accounts payable and accrued liabilities	3,577	4,133
Deferred revenue	(25,590)	26,086
Operating lease liability	(580)	(509)
Net cash used in operating activities	(26,968)	(519)
Investing activities
Purchases of property and equipment	(296)	(69)
Purchase of investments	(120,335)	(99,957)
Maturities of investments	115,182	51,831
Net cash used in investing activities	(5,449)	(48,195)
Financing activities
Proceeds from sale of common stock and warrants, net of offering costs	94,004	90,812
Repayment of debt	(3,600)	(1,200)
Proceeds from exercise of stock options	742	279
Net cash provided by financing activities	91,146	89,891
Effect of exchange rate on cash and cash equivalents	(11)	(37)
Net increase in cash and cash equivalents and restricted cash	58,718	41,140
Cash and cash equivalents and restricted cash, beginning of period	68,161	35,213
Cash and cash equivalents and restricted cash, end of period	126,879	76,353
Supplemental Information
Cash paid for interest	$ 262	$ 432

XML

Description of Business

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business

Description of Business

Alpine Immune Sciences, Inc. (the “Company”, “Alpine”, “we”, “us”, or “our”), together with its consolidated subsidiaries, is a clinical-stage biopharmaceutical company dedicated to discovering and developing innovative, protein-based immunotherapies to treat inflammatory and autoimmune diseases. Our approach includes a proprietary scientific platform that converts native immune system proteins into differentiated, multi-targeted therapeutics. We are seeking to create first- or best-in-class multifunctional immunotherapies via our unique protein engineering technologies to improve outcomes in patients with serious diseases. We were incorporated under the laws of the State of Delaware and are headquartered in Seattle, Washington.

As a result of the COVID-19 pandemic, many companies have experienced disruptions in their operations and in markets served. We have implemented temporary precautionary measures to ensure the well-being of our employees and minimize business disruption. We considered the impact of COVID-19 on the assumptions and estimates used and determined that there were no material adverse impacts to our results of operations and financial position at September 30, 2022. The full extent of the future impacts of the continuing COVID-19 pandemic on our operations is uncertain and may adversely impact our business, including our clinical trials.

XML

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

Basis of Presentation and Use of Estimates

The accompanying condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) and generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Significant estimates inherent in the preparation of the accompanying condensed consolidated financial statements include those used for revenue recognition, accruals for clinical trial activities and other accruals, the potential outcome of uncertain tax positions that have been recognized in our condensed consolidated financial statements or tax returns, and the estimated fair value of equity-based awards. We base our estimates and assumptions on historical experience when available and on various factors we believe to be reasonable under the circumstances. Actual results could differ materially from those estimates.

The accompanying condensed consolidated financial statements as of September 30, 2022 and for the three and nine months ended September 30, 2022 and 2021 and the related interim information contained within the notes to the condensed consolidated financial statements are unaudited. The interim financial statements have been prepared on the same basis as the audited financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The accompanying condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and accompanying notes for the year ended December 31, 2021 included in our Annual Report on Form 10-K for the year ended December 31, 2021, filed with the SEC on March 17, 2022 (“Annual Report”). The results of our operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year.

Principles of Consolidation

Our condensed consolidated financial statements include the financial position and results of operations of Alpine Immune Sciences, Inc. and our wholly owned operating company and subsidiary, AIS Operating Co., Inc., and our wholly-owned subsidiary, Alpine Immune Sciences Australia PTY LTD. All inter-company balances and transactions have been eliminated in consolidation. 

Cash and Cash Equivalents and Restricted Cash

We consider all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of deposits with commercial banks in checking and interest-bearing accounts, and highly liquid money market funds.

Restricted cash represents cash drawn on our line of credit used to establish collateral to support the security deposit on our operating lease to rent office and laboratory space in Seattle, Washington.

Periodically, we maintain deposits in financial institutions in excess of government insured limits. We believe we are not exposed to significant credit risk as our deposits, which are held at financial institutions, are high credit quality securities such as money market funds, U.S. Treasury securities, and commercial paper. To date, we have not realized any losses on these deposits.

Investments

Our investments include funds invested in highly liquid money market funds, U.S. Treasury securities, commercial paper, and corporate debt securities with a final maturity of each security of less than two years. These investments are classified as available-for-sale debt securities, which are recorded at fair value based on quoted prices in active markets. We classify our investments maturing within one year of the reporting date as short-term investments.

If the estimated fair value of a debt security is below its amortized cost basis, we evaluate whether it is more likely than not that we will sell the security before its anticipated recovery in market value and whether credit losses exist for the related securities. A credit loss exists if the present value of expected cash flows is less than the amortized cost basis of the security. Credit-related losses are recognized as an allowance for credit losses on the balance sheet with a corresponding adjustment to earnings. Unrealized gains and losses that are unrelated to credit deterioration are reported in other comprehensive income (loss). Purchase premiums and discounts are recognized as interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value deemed to be other than temporary are reflected in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) using the specific-identification method.

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Net Loss Per Share

9 Months Ended

Sep. 30, 2022

Earnings Per Share [Abstract]

Net Loss Per Share

Net Loss Per Share

Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period.

The net loss per share for the three and nine months ended September 30, 2022 partially reflects 13,606,000 shares of common stock sold in September 2022 through an underwritten public offering. Additionally, we issued 6,489,357 shares of our common stock pursuant to a private placement financing completed in September 2021 and 951,980 shares of our common stock issued in December 2021 pursuant to a private placement financing with Horizon Therapeutics Ireland DAC (“Horizon”). The increased number of shares issued during the periods presented impacts the year-over-year comparability of our net loss per share calculations.

The common stock issuable upon the conversion or exercise of the following dilutive securities has been excluded from the diluted net loss per share calculation because their effect would have been anti-dilutive. Diluted net loss per share, therefore, does not differ from basic net loss per share for the periods presented.

	September 30,
	2022	2021
	(unaudited)
Warrants to purchase common stock	8,838,694	8,851,116
Stock options and restricted stock units outstanding	7,327,631	5,692,264
Total	16,166,325	14,543,380

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Cash Equivalents and Investments

9 Months Ended

Sep. 30, 2022

Investments and Cash [Abstract]

Cash Equivalents and Investments

Cash Equivalents and Investments

The amortized cost and fair value of our cash equivalents and investments are as follows (in thousands):

	September 30, 2022
	(unaudited)
Assets:	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair market value
Money market funds	$	121,916	$	—	$	—	$	121,916
U.S. treasury bills	53,660		—		(804)		52,856
Corporate debt securities and commercial paper	98,215		—		(818)		97,397
Total	$	273,791	$	—	$	(1,622)	$	272,169
Classified as:
Cash equivalents							$	121,916
Short-term investments							122,237
Long-term investments							28,016
Total							$	272,169

	December 31, 2021
Assets:	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair market value
Money market funds	$	50,277	$	—	$	—	$	50,277
U.S. treasury bills	30,006		1		(100)		29,907
Corporate debt securities and commercial paper	117,492		2		(139)		117,355
Total	$	197,775	$	3	$	(239)	$	197,539
Classified as:
Cash equivalents							$	50,277
Short-term investments							94,396
Long-term investments							52,866
Total							$	197,539

All investments held as of September 30, 2022 and December 31, 2021 were classified as available-for-sale debt securities and had contractual maturities of less than two years. There were no realized gains and losses on these securities for the periods presented. The aggregate fair value of available-for-sale debt securities in an unrealized loss position as of September 30, 2022 and December 31, 2021 was $123.2 million and $83.0 million, respectively. Investments in a continuous unrealized loss position for more than twelve months related to our U.S. treasury bills, corporate debt securities and commercial paper, which had a carrying value of $26.0 million and gross unrealized losses of $0.5 million as of September 30, 2022 and none as of December 31, 2021. Our available-for-sale debt securities are invested in highly liquid funds with high credit ratings that have a final maturity of two years or less on the date of purchase. Unrealized losses on these investments were primarily due to changes in interest rates. We evaluated our investments that are in an unrealized loss position and believe it is more likely than not that we will hold these investments until maturity and will recover the amortized cost basis of these investments.

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Fair Value Measurements

9 Months Ended

Sep. 30, 2022

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

Cash and cash equivalents, restricted cash, receivables, accounts payable and accrued liabilities, which are recorded at invoiced amount or cost, approximate fair value based on the short-term nature of these financial instruments. Fair value is defined as the exchange price received for an asset or paid to transfer a liability, or an exit price, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, is as follows:

Level 1: Quoted prices in active markets for identical assets or liabilities.

Level 2: Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3: Unobservable inputs supported by little or no market activity and significant to the fair value of the assets or liabilities.

As of September 30, 2022 and December 31, 2021, cash of $4.7 million and $17.6 million, respectively, is excluded from the fair value table below. The following tables summarize our financial assets and liabilities measured at fair value on a recurring basis (in thousands):

	September 30, 2022
	(unaudited)
Assets:	Level 1		Level 2		Level 3		Total
Money market funds	$	121,916	$	—	$	—	$	121,916
U.S. treasury bills	52,856		—		—		52,856
Corporate debt securities and commercial paper	—		97,397		—		97,397
Total	$	174,772	$	97,397	$	—	$	272,169

	December 31, 2021
Assets:	Level 1		Level 2		Level 3		Total
Money market funds	$	50,277	$	—	$	—	$	50,277
U.S. treasury bills	29,907		—		—		29,907
Corporate debt securities and commercial paper	—		117,355		—		117,355
Total	$	80,184	$	117,355	$	—	$	197,539

Our Level 2 assets consist of commercial paper and corporate debt securities. We review trading activity and pricing for our available-for-sale securities as of the measurement date. When sufficient quoted pricing for identical securities is not available, we use market pricing and other observable market inputs for similar securities obtained from various third-party data providers. These inputs either represent quoted prices for similar assets in active markets or have been derived from observable market data.

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Additional Balance Sheet Information

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Additional Balance Sheet Information

Additional Balance Sheet InformationPrepaid expenses and other current assets consist of the following (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Prepaid research and development	$	2,723	$	3,315
Prepaid insurance	547		454
Prepaid other	430		266
Deferred financing	—		352
Other receivables	295		323
Prepaid expenses and other current assets	$	3,995	$	4,710

Accrued liabilities consist of the following (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Research and development services	$	8,293	$	5,536
Employee compensation	3,380		3,084
Accrued taxes	1,211		127
Legal and professional fees	822		394
Accrued other	38		276
Accrued liabilities	$	13,744	$	9,417

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Long-term Debt

9 Months Ended

Sep. 30, 2022

Debt Disclosure [Abstract]

Long-term Debt

Long-term Debt

In August 2019, we entered into an Amended and Restated Loan and Security Agreement (the “Loan Agreement”) with Silicon Valley Bank (“SVB”), pursuant to which SVB agreed to extend term loans to us with an aggregate principal amount of up to $15.0 million (the “Term Loans”). Borrowings under the Loan Agreement consisted of up to three separate tranches. The initial tranche of $5.0 million was funded in August 2019, $3.0 million of which was used to repay amounts owing under our prior loan and security agreement with SVB. In March 2020, the second tranche of $5.0 million was funded to us. We did not draw down the final tranche of $5.0 million, which expired in July 2020.

The Term Loans accrue interest at a floating per annum rate of 0.25% above the prime rate, subject to a floor of 5.75%, which interest is payable monthly commencing in September 2019. Upon the occurrence and during the continuance of an event of default, a default interest rate will apply that is 4.0% above the otherwise applicable interest rate. The Term Loans were interest only until September 30, 2020, however, under the Loan Agreement our interest only period automatically extended to June 30, 2021 if we received aggregate new capital of at least $40.0 million no later than June 30, 2020. We met this milestone in June 2020 in conjunction with the execution of the agreement with AbbVie Ireland Unlimited Company (“AbbVie”), discussed in detail in Note 9. As a result of the interest only extension, the Term Loans are payable in 25 equal monthly installments of principal plus interest, with the final installment due and payable on July 1, 2023.

We may prepay all, but not less than all, of the Term Loans subject to a prepayment fee equal to $75,000. Additionally, a final payment in the amount of 5.5% of the funded Term Loans is payable to SVB on the date on which the Term Loans are prepaid, paid or become due and payable in full. The final payment fees are recorded in long-term debt in our accompanying Condensed Consolidated Balance Sheets.

The Loan Agreement contains customary representations and warranties, events of default and affirmative and negative covenants. We were in compliance with our covenants as of September 30, 2022. As such, as of September 30, 2022, the classification of the loan is split between current and noncurrent based on the timing of payment obligations. As security for our obligations under the Loan Agreement, we granted SVB a first priority security interest on substantially all of our assets, except intellectual property, and subject to certain other exceptions.

In connection with the Loan Agreement, we issued a warrant to SVB to purchase up to 52,083 shares of our common stock at a price of $4.32 per share, 17,361 shares of which became exercisable in August 2019 after we drew down the initial tranche. In March 2020, after we drew down the second tranche of our Term Loan, an additional 17,361 shares became exercisable. The remaining warrants did not vest and expired upon the expiration of the third tranche of our Term Loan. The fair value of the warrants on the date of issuance for the initial tranche and second tranche was $60,000 and $60,000, respectively, determined using the Black-Scholes option-pricing model, and was recorded as a component of equity and as a debt discount in our accompanying Condensed Consolidated Balance Sheets.

We recorded a total debt discount of $812,000 in connection with the Loan Agreement, which is being amortized to interest expense using the effective interest method over the repayment term of the loan. The unamortized discount included in long-term debt in our accompanying Condensed Consolidated Balance Sheets was $78,000 as of September 30, 2022. Interest expense associated with the amortization of the discount is recorded as non-cash interest expense on our accompanying Condensed Consolidated Statements of Cash Flows.

Scheduled principal payments on our outstanding debt as of September 30, 2022 under our Loan Agreement, excluding final payment fees, are as follows (in thousands):

	Total
Year ending December 31,	(unaudited)
2022 (remainder of year)	$	1,200
2023	2,800
Total future principal payments	$	4,000

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Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Contingencies	ContingenciesCertain credits received related to our research and development expenditures and previously recorded within other income in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) are subject to review by foreign taxing authorities. Upon reaching constructive agreement with the Australian Taxation Office during the quarter ended June 30, 2022, we recorded an estimated current foreign income tax provision of $1.3 million for the expected repayments, which is included within accrued liabilities on our accompanying Condensed Consolidated Balance Sheets.

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License and Collaboration Agreements

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

License and Collaboration Agreements

License and Collaboration Agreements

AbbVie

In June 2020, we entered into an option and license agreement with AbbVie (the “AbbVie Agreement”) for the development of ALPN-101, (“acazicolcept”). The AbbVie Agreement grants AbbVie the exclusive option to purchase an exclusive worldwide license to acazicolcept (the “License Option”). The License Option is exercisable by AbbVie at any time and will expire 90 days from the achievement of certain development milestones. If AbbVie exercises the License Option, AbbVie will take over the future development and commercialization. Prior to the exercise of the License Option, we will perform research and development services, including conducting our Phase 2 study in systemic lupus erythematosus, based on an agreed-upon development plan (the “Development Plan”). We will be fully responsible for all costs incurred to conduct the activities under the Development Plan, provided that, AbbVie may be responsible for increased costs under the Development Plan in connection with certain material amendments proposed by AbbVie. We will also be solely responsible, at our sole cost and expense, for manufacturing and regulatory filings for acazicolcept necessary to complete activities under the Development Plan.

In June 2020, in connection with the execution of the AbbVie Agreement, AbbVie paid us a nonrefundable upfront payment of $60.0 million. Prior to the exercise of the License Option, AbbVie has agreed to make cash payments upon our achievement of certain predefined pre-option development milestones (the “Alpine Development Milestones”) up to an aggregate amount of $75.0 million. In 2021, we received $45.0 million of the Alpine Development Milestones. If AbbVie exercises the License Option, they will pay a one-time cash payment of $75.0 million. Following the exercise of the License Option, AbbVie has also agreed to make aggregate cash payments of up to $205.0 million upon AbbVie’s achievement of certain development and commercial milestones and additional aggregate cash payments of up to $450.0 million upon AbbVie’s achievement of certain sales-based cash milestones, collectively referred to as (the “AbbVie Milestones”). Subsequent to commercialization, we are also eligible to receive high single-digit to low double-digit percentage royalties on worldwide net sales of licensed products.

For revenue recognition purposes, we determined that our contractual promises in the AbbVie Agreement are not distinct and are interdependent with our performance obligation to provide research and development services under the Development Plan. Thus, all contractual promises related to the upfront payment and Alpine’s Development Milestones were combined into a single performance obligation. We determined the Alpine Development Milestone payments are probable of significant revenue reversal as the achievement is highly dependent on factors outside our control. Therefore, these milestone payments were fully constrained and were not initially included in the transaction price. In June 2021, we re-evaluated and updated the transaction price to include the achieved portion of the Alpine Development Milestones. We will continue to re-evaluate the transaction price each reporting period and update as uncertain events are resolved or other changes in circumstances occur. We expect to recognize the remaining deferred revenue over the remaining life of the Development Plan, which began in June 2020 and ends upon the later of the exercise or expiration of the option.

The License Option and the AbbVie Milestones were determined not to be performance obligations at the inception of the contract as they did not represent material rights. If exercised, the License Option and AbbVie Milestones will be accounted

for as a separate contract and will be recognized as revenue if and when triggered. Any consideration related to sales-based royalties and profit-sharing payments will be recognized when the related sales occur.

Horizon

In December 2021, we entered into an exclusive license and collaboration agreement with Horizon (the “Horizon Agreement”) for the development and commercialization of up to four preclinical candidates generated from our unique discovery platform. The agreement includes licensing of one of our existing preclinical biologic therapeutic programs (the “Existing Program”), as well as a research partnership to jointly develop candidates for up to three additional autoimmune and inflammatory disease programs for other designated biological targets (the “Research Programs”). These candidates include previously undisclosed multi-specific fusion protein-based therapeutic candidates for autoimmune and inflammatory diseases. We will advance candidate molecules to predefined preclinical milestones while Horizon will be responsible for the respective costs and, ultimately, Horizon will assume responsibility for development and commercialization activities and costs.

In connection with the execution of the Horizon Agreement in December 2021, we entered into a stock purchase agreement under which Horizon purchased 951,980 shares of our common stock in a private placement for approximately $15.76 per share and aggregate proceeds of $15.0 million. The shares were sold at a 25% premium to the volume-weighted average share price of our common stock for a specified 30-day period prior to entering into the agreement. The fair value of the common stock issued to Horizon of $11.9 million was recorded to equity, based on the closing price of common stock on the effective date of the Horizon Agreement. For accounting purposes, the $3.1 million difference between the cash proceeds and the fair value of the common stock was treated as additional consideration attributable to the Horizon Agreement.

Under the terms of the agreements, Horizon also paid us a non-refundable upfront payment of $25.0 million in the first quarter of 2022. In addition, we are eligible to receive up to $381.0 million per program, or up to approximately $1.5 billion in total, in future success-based payments related to development, regulatory and commercial milestones. Furthermore, we are eligible to receive tiered royalties from a mid-single digit percentage to a low double-digit percentage on global net sales. In addition to proceeds from the non-refundable upfront payment, we have recognized $446,000 in research and development support for ongoing programs through September 30, 2022.

For revenue recognition purposes, we determined the transaction price at inception was $28.1 million, which consists of the upfront payment of $25.0 million and the $3.1 million premium on the stock purchase, and that the Existing Program and each Research Program are distinct performance obligations. We allocated revenue to each performance obligation based on its relative stand-alone selling price. The future success-based payments related to development and regulatory milestones are probable of significant revenue reversal as the achievement is highly dependent on factors outside our control. Therefore, these milestone payments are fully constrained and are not initially included in the transaction price. We will continue to re-evaluate the transaction price each reporting period and update as uncertain events are resolved or other changes in circumstances occur. Any consideration related to commercial milestones and royalties will be recognized when the related sales occur.

Adaptimmune

In May 2019, we entered into a collaboration and licensing agreement with Adaptimmune Therapeutics plc (“Adaptimmune”) to develop next-generation SPEAR T cell products (the “Adaptimmune Agreement”). Under the Adaptimmune Agreement, we are to perform certain research services and grant Adaptimmune an exclusive license to programs from our secreted immunomodulatory protein (“SIP”) and transmembrane immunomodulatory protein (“TIP”) technologies.

Through September 30, 2022, we have recorded a total of $3.0 million in license payments under the terms of the Adaptimmune Agreement consisting of a $2.0 million upfront license payment received in June 2019 and an additional $1.0 million license fee upon Adaptimmune’s selection of an additional research program in June 2022. In addition, we have recorded $1.9 million in research support payments to fund ongoing programs through September 30, 2022. In addition, we are eligible for research support payments, one-time payments and downstream development and commercialization milestones of up to $288.0 million, if respective pre-specified milestones for each program are achieved. We are also eligible to receive low-single digit percentage royalties on worldwide net sales of the applicable products.

For revenue recognition purposes, licensing and research support fees billed under the agreement are being recorded as deferred revenue and recognized to revenue based on employee hours contributed to each performance obligation.

Contract balances and revenue recognition

We report contract assets resulting from unconditional rights to consideration related to upfront payments, and for completed but unpaid research and development services within accounts receivable in our accompanying Condensed Consolidated Balance Sheets. Contract liabilities, representing advance consideration for licensing rights bundled with research

and development services and other promises for which the underlying performance obligations have not yet been satisfied, are reported as deferred revenue in our accompanying Condensed Consolidated Balance Sheets. Contract liabilities are presented as current and noncurrent based on estimated timing of when the underlying performance obligations will be met. Respective balances are as follows (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Contract Assets	$	382	$	25,000
Contract Liabilities	$	77,013	$	102,603

We use cost-based input methods to measure progress towards completion of our performance obligations and to calculate the corresponding revenue to recognize under our contracts with customers each period. In applying the cost-based input, we use actual costs incurred relative to budgeted costs for each combined performance obligation. Actual costs consist primarily of labor related to internal personnel and third-party contracts. Revenue is recognized based on the level of costs incurred relative to the total estimated costs for the performance obligation. A cost-based input method of revenue recognition requires management to make estimates of costs to complete our performance obligations. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete our performance obligations will be recorded in the period in which changes are identified and amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods.

Collaboration revenue in our accompanying Condensed Consolidated Statements of Operations and Comprehensive Income (Loss), disaggregated by customer, is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
AbbVie	$	6,632	$	8,516	$	17,155	$	18,913
Horizon	1,279		—		9,535		—
Adaptimmune	456		—		598		—
Total collaboration revenue	$	8,367	$	8,516	$	27,288	$	18,913

Revenue recognized during the period that was included in the opening contract liability balance was $26.3 million and $18.9 million for the nine months ended September 30, 2022 and 2021, respectively.

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Stockholders’ Equity

9 Months Ended

Sep. 30, 2022

Stockholders' Equity Note [Abstract]

Stockholders’ Equity

Stockholders’ Equity

Securities Offering and Financing Agreement

In September 2022, we sold 13,606,000 shares of our common stock in an underwritten public offering pursuant to our effective shelf registration statement on Form S-3 (File No. 333-256107), resulting in net proceeds of $93.5 million to us, after deducting underwriting discounts, commissions and estimated offering costs. Accrued legal and professional fees of $550,000 incurred in connection with the public offering have been recorded as a reduction to the $94.0 million cash proceeds within additional-paid-in-capital on our accompanying Condensed Consolidated Balance Sheets. An additional 1,903,282 shares of our common stock were sold pursuant to the underwriters’ partial exercise of their over-allotment option, with net proceeds of $13.1 million, after deducting underwriting discounts and commissions, received upon closing on October 4, 2022.

In September 2022, we and Cowen and Company, LLC (“Cowen”) mutually terminated the sales agreement (the “Sales Agreement”) dated July 2, 2021.The Sales Agreement provided that we may sell shares of our common stock from time to time through an “at the market” equity offering for up to $75.0 million in gross cash proceeds, under which Cowen acted as the sales agent. No shares of our common stock were sold under the Sales Agreement. In connection with the termination of the Sales Agreement, we wrote off $488,000 of deferred financing costs to expense, which were previously included within prepaid expenses and other current assets on our accompanying Condensed Consolidated Balance Sheets.

Equity Incentive Plans

On January 1, 2022, in connection with our 2018 Equity Incentive Plan (the “2018 Plan”) annual increase provision, a total of 1,500,000 additional shares were automatically added to the shares authorized under the 2018 Plan.

During the nine months ended September 30, 2022, we issued stock option grants totaling 1,891,150 shares with a weighted average exercise price of $10.99 per share and 3,750 shares of restricted stock units (“RSUs”) at a grant date fair value of $9.00 per share to eligible employees and board members.

Stock-Based Compensation Expense 

We use the Black-Scholes option pricing model to estimate the fair value of stock options at the grant date. The fair value of RSUs is equal to the closing stock price on the date of grant. We recognize the fair value of stock-based compensation as compensation expense over the requisite service period, which is the vesting period. Stock-based compensation is classified in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) as follows (in thousands): 

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
Research and development	$	1,558	$	936	$	4,212	$	2,596
General and administrative	997		702		2,967		2,184
Total stock-based compensation expense	$	2,555	$	1,638	$	7,179	$	4,780

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Income Taxes

9 Months Ended

Sep. 30, 2022

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

We are subject to income taxes in the United States and Australia and our effective tax rate is calculated quarterly based upon current assumptions relating to the full year’s estimated operating results and various tax-related items. Each quarter an estimate of the annual effective tax rate is updated should we revise our forecast of earnings based upon our operating results. If there is a change in the estimated effective annual tax rate, a cumulative adjustment is made. Our effective tax rate was 4.82% and 0.61% for the nine months ended September 30, 2022 and 2021, respectively.

The increase in our effective tax rate was primarily due to recognizing current income tax liabilities of $1.3 million during the quarter ended June 30, 2022, which was a result of a cumulative change to our foreign income tax provision for the activities of our wholly owned subsidiary, Alpine Immune Sciences Australia PTY LTD. Following notification of acceptance received during the quarter ended June 30, 2022 of Alpine Immune Sciences Australia PTY LTD’s tax return filed under a revised transfer pricing model for the six-months period ended December 31, 2019, the tax provisions for each open tax year have been recalculated using the same transfer pricing methodology underlying the accepted return. Additionally, consistent with the change to our transfer pricing methodology, we recorded $0.1 million of deferred tax expense resulting from a reduction to our deferred tax assets during the quarter ended June 30, 2022.

The increase in our effective tax rate during the nine months ended September 30, 2022 was also impacted by recognizing current domestic federal income tax liabilities of $0.4 million, which was a result of the mandatory capitalization of research and development expenses under Internal Revenue Code Section 174. As part of the Tax Cuts and Jobs Act of 2017 (TCJA), beginning with the 2022 tax year, expenses that are incurred for research and development in the U.S. will be capitalized and amortized over five years, and expenses that are incurred for research and experimentation outside the U.S. will be capitalized and amortized over 15 years.

The difference between the effective tax rate of 4.82% and the U.S. federal statutory rate of 21% for the nine months ended September 30, 2022, was primarily due to recognizing a full valuation allowance on our domestic deferred tax assets and partial valuation allowance on our foreign deferred tax assets, tax expense resulting from the acceptance of a Voluntary Disclosure Agreement with the Australian Taxation Office, and tax benefits relating to research and development tax credits.

The difference between the effective tax rate of 0.61% and the U.S. federal statutory rate of 21% for the nine months ended September 30, 2021, was primarily due to recognizing a full valuation allowance on our domestic deferred tax assets and partial valuation allowance on our foreign deferred tax assets.

As of September 30, 2022, we determined that, based on an evaluation of our sources of income and all available evidence, both positive and negative, including our latest forecasts and cumulative losses in recent years, it was more likely than not that none of our domestic deferred tax assets would be realized and therefore we continued to record a full domestic valuation allowance. As of September 30, 2022, we determined that it was more likely than not that only a portion of our foreign deferred tax assets would be realized and have recorded a partial foreign valuation allowance.

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Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2022

Accounting Policies [Abstract]

Basis of Presentation and Use of Estimates

Basis of Presentation and Use of Estimates

The accompanying condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) and generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make judgments, estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Significant estimates inherent in the preparation of the accompanying condensed consolidated financial statements include those used for revenue recognition, accruals for clinical trial activities and other accruals, the potential outcome of uncertain tax positions that have been recognized in our condensed consolidated financial statements or tax returns, and the estimated fair value of equity-based awards. We base our estimates and assumptions on historical experience when available and on various factors we believe to be reasonable under the circumstances. Actual results could differ materially from those estimates.

The accompanying condensed consolidated financial statements as of September 30, 2022 and for the three and nine months ended September 30, 2022 and 2021 and the related interim information contained within the notes to the condensed consolidated financial statements are unaudited. The interim financial statements have been prepared on the same basis as the audited financial statements and in the opinion of management, reflect all normal recurring adjustments necessary for a fair statement of our financial position for the interim periods presented. The accompanying condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements and accompanying notes for the year ended December 31, 2021 included in our Annual Report on Form 10-K for the year ended December 31, 2021, filed with the SEC on March 17, 2022 (“Annual Report”). The results of our operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year.

Principles of Consolidation

Principles of ConsolidationOur condensed consolidated financial statements include the financial position and results of operations of Alpine Immune Sciences, Inc. and our wholly owned operating company and subsidiary, AIS Operating Co., Inc., and our wholly-owned subsidiary, Alpine Immune Sciences Australia PTY LTD. All inter-company balances and transactions have been eliminated in consolidation.

Cash and Cash Equivalents and Restricted Cash

Cash and Cash Equivalents and Restricted Cash

We consider all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of deposits with commercial banks in checking and interest-bearing accounts, and highly liquid money market funds.

Restricted cash represents cash drawn on our line of credit used to establish collateral to support the security deposit on our operating lease to rent office and laboratory space in Seattle, Washington.

Periodically, we maintain deposits in financial institutions in excess of government insured limits. We believe we are not exposed to significant credit risk as our deposits, which are held at financial institutions, are high credit quality securities such as money market funds, U.S. Treasury securities, and commercial paper. To date, we have not realized any losses on these deposits.

Investments

Investments

Our investments include funds invested in highly liquid money market funds, U.S. Treasury securities, commercial paper, and corporate debt securities with a final maturity of each security of less than two years. These investments are classified as available-for-sale debt securities, which are recorded at fair value based on quoted prices in active markets. We classify our investments maturing within one year of the reporting date as short-term investments.

If the estimated fair value of a debt security is below its amortized cost basis, we evaluate whether it is more likely than not that we will sell the security before its anticipated recovery in market value and whether credit losses exist for the related securities. A credit loss exists if the present value of expected cash flows is less than the amortized cost basis of the security. Credit-related losses are recognized as an allowance for credit losses on the balance sheet with a corresponding adjustment to earnings. Unrealized gains and losses that are unrelated to credit deterioration are reported in other comprehensive income (loss). Purchase premiums and discounts are recognized as interest income using the interest method over the terms of the securities. Realized gains and losses and declines in fair value deemed to be other than temporary are reflected in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) using the specific-identification method.

Net Loss Per Share

Net Loss Per ShareBasic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period.

Fair Value Measurements

Fair Value Measurements

Cash and cash equivalents, restricted cash, receivables, accounts payable and accrued liabilities, which are recorded at invoiced amount or cost, approximate fair value based on the short-term nature of these financial instruments. Fair value is defined as the exchange price received for an asset or paid to transfer a liability, or an exit price, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value, is as follows:

Level 1: Quoted prices in active markets for identical assets or liabilities.

Level 2: Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3: Unobservable inputs supported by little or no market activity and significant to the fair value of the assets or liabilities.

Stock-Based Compensation Expense

Stock-Based Compensation Expense We use the Black-Scholes option pricing model to estimate the fair value of stock options at the grant date. The fair value of RSUs is equal to the closing stock price on the date of grant. We recognize the fair value of stock-based compensation as compensation expense over the requisite service period, which is the vesting period.

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Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2022

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Diluted Net Loss Per Share Attributable to Common Stockholders

The common stock issuable upon the conversion or exercise of the following dilutive securities has been excluded from the diluted net loss per share calculation because their effect would have been anti-dilutive. Diluted net loss per share, therefore, does not differ from basic net loss per share for the periods presented.

	September 30,
	2022	2021
	(unaudited)
Warrants to purchase common stock	8,838,694	8,851,116
Stock options and restricted stock units outstanding	7,327,631	5,692,264
Total	16,166,325	14,543,380

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Cash Equivalents and Investments (Tables)

9 Months Ended

Sep. 30, 2022

Investments and Cash [Abstract]

Schedule of Amortized Cost and Fair Value of Cash Equivalents and Investments

The amortized cost and fair value of our cash equivalents and investments are as follows (in thousands):

	September 30, 2022
	(unaudited)
Assets:	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair market value
Money market funds	$	121,916	$	—	$	—	$	121,916
U.S. treasury bills	53,660		—		(804)		52,856
Corporate debt securities and commercial paper	98,215		—		(818)		97,397
Total	$	273,791	$	—	$	(1,622)	$	272,169
Classified as:
Cash equivalents							$	121,916
Short-term investments							122,237
Long-term investments							28,016
Total							$	272,169

	December 31, 2021
Assets:	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair market value
Money market funds	$	50,277	$	—	$	—	$	50,277
U.S. treasury bills	30,006		1		(100)		29,907
Corporate debt securities and commercial paper	117,492		2		(139)		117,355
Total	$	197,775	$	3	$	(239)	$	197,539
Classified as:
Cash equivalents							$	50,277
Short-term investments							94,396
Long-term investments							52,866
Total							$	197,539

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Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2022

Fair Value Disclosures [Abstract]

Schedule of Financial Assets Measured at Fair Value on Recurring Basis

The following tables summarize our financial assets and liabilities measured at fair value on a recurring basis (in thousands):

	September 30, 2022
	(unaudited)
Assets:	Level 1		Level 2		Level 3		Total
Money market funds	$	121,916	$	—	$	—	$	121,916
U.S. treasury bills	52,856		—		—		52,856
Corporate debt securities and commercial paper	—		97,397		—		97,397
Total	$	174,772	$	97,397	$	—	$	272,169

	December 31, 2021
Assets:	Level 1		Level 2		Level 3		Total
Money market funds	$	50,277	$	—	$	—	$	50,277
U.S. treasury bills	29,907		—		—		29,907
Corporate debt securities and commercial paper	—		117,355		—		117,355
Total	$	80,184	$	117,355	$	—	$	197,539

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Additional Balance Sheet Information (Tables)

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Prepaid research and development	$	2,723	$	3,315
Prepaid insurance	547		454
Prepaid other	430		266
Deferred financing	—		352
Other receivables	295		323
Prepaid expenses and other current assets	$	3,995	$	4,710

Schedule of Accrued Liabilities

Accrued liabilities consist of the following (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Research and development services	$	8,293	$	5,536
Employee compensation	3,380		3,084
Accrued taxes	1,211		127
Legal and professional fees	822		394
Accrued other	38		276
Accrued liabilities	$	13,744	$	9,417

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Long-term Debt (Tables)

9 Months Ended

Sep. 30, 2022

Debt Disclosure [Abstract]

Schedule of Maturities of Long-term Debt

Scheduled principal payments on our outstanding debt as of September 30, 2022 under our Loan Agreement, excluding final payment fees, are as follows (in thousands):

	Total
Year ending December 31,	(unaudited)
2022 (remainder of year)	$	1,200
2023	2,800
Total future principal payments	$	4,000

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License and Collaboration Agreements (Tables)

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Contract Balances

Contract liabilities are presented as current and noncurrent based on estimated timing of when the underlying performance obligations will be met. Respective balances are as follows (in thousands):

	September 30, 2022		December 31, 2021
	(unaudited)
Contract Assets	$	382	$	25,000
Contract Liabilities	$	77,013	$	102,603

Schedule of Disaggregation of Revenue

Collaboration revenue in our accompanying Condensed Consolidated Statements of Operations and Comprehensive Income (Loss), disaggregated by customer, is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
AbbVie	$	6,632	$	8,516	$	17,155	$	18,913
Horizon	1,279		—		9,535		—
Adaptimmune	456		—		598		—
Total collaboration revenue	$	8,367	$	8,516	$	27,288	$	18,913

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Stockholders’ Equity (Tables)

9 Months Ended

Sep. 30, 2022

Stockholders' Equity Note [Abstract]

Schedule of Stock-based Compensation Expense

Stock-based compensation is classified in our Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) as follows (in thousands): 

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
	(unaudited)
Research and development	$	1,558	$	936	$	4,212	$	2,596
General and administrative	997		702		2,967		2,184
Total stock-based compensation expense	$	2,555	$	1,638	$	7,179	$	4,780

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Summary of Significant Accounting Policies (Details)	Sep. 30, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Debt securities, available-for-sale, term (less than)	2 years	2 years

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Net Loss Per Share - Narrative (Details) - shares	1 Months Ended		3 Months Ended		9 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022
2021 PIPE
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Issuance of Units/common stock, net of offering costs (in shares)		6,489,357
Horizon
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Issuance of Units/common stock, net of offering costs (in shares)	951,980
Common Stock
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Issuance of Units/common stock, net of offering costs (in shares)			13,606,000	6,489,357	13,606,000

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Net Loss Per Share - Schedule of Anti-dilutive Securities (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	16,166,325	14,543,380
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	8,838,694	8,851,116
Stock options and restricted stock units outstanding
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	7,327,631	5,692,264

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Cash Equivalents and Investments - Summary of Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 273,791	$ 197,775
Gross unrealized gains	0	3
Gross unrealized losses	(1,622)	(239)
Fair market value	272,169	197,539
Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Fair market value	121,916	50,277
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Fair market value	122,237	94,396
Long-term investments
Debt Securities, Available-for-sale [Line Items]
Fair market value	28,016	52,866
Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	121,916	50,277
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair market value	121,916	50,277
U.S. treasury bills
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	53,660	30,006
Gross unrealized gains	0	1
Gross unrealized losses	(804)	(100)
Fair market value	52,856	29,907
Corporate debt securities and commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	98,215	117,492
Gross unrealized gains	0	2
Gross unrealized losses	(818)	(139)
Fair market value	$ 97,397	$ 117,355

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Cash Equivalents and Investments - Narrative (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Investments and Cash [Abstract]
Debt securities, available-for-sale, term (less than)	2 years		2 years
Realized gains (losses) on securities	$ 0	$ 0
Available-for-sale debt securities in unrealized loss position	123,200,000		$ 83,000,000
Security of carrying amount	26,000,000
Gross unrealized loss	$ 500,000		$ 0

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Fair Value Measurements- Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Cash	$ 4.7	$ 17.6

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Fair Value Measurements - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	$ 272,169	$ 197,539
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	174,772	80,184
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	97,397	117,355
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	0	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	121,916	50,277
Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	121,916	50,277
Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	0	0
Money market funds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	0	0
U.S. treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	52,856	29,907
U.S. treasury bills | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	52,856	29,907
U.S. treasury bills | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	0	0
U.S. treasury bills | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	0	0
Corporate debt securities and commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	97,397	117,355
Corporate debt securities and commercial paper | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	0	0
Corporate debt securities and commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	97,397	117,355
Corporate debt securities and commercial paper | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value assets disclosure	$ 0	$ 0

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Additional Balance Sheet Information - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepaid research and development	$ 2,723	$ 3,315
Prepaid insurance	547	454
Prepaid other	430	266
Deferred financing	0	352
Other receivables	295	323
Prepaid expenses and other current assets	$ 3,995	$ 4,710

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Additional Balance Sheet Information - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and development services	$ 8,293	$ 5,536
Employee compensation	3,380	3,084
Accrued taxes	1,211	127
Legal and professional fees	822	394
Accrued other	38	276
Accrued liabilities	$ 13,744	$ 9,417

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Long-term Debt - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended
	Mar. 31, 2020 USD ($)	Aug. 31, 2019 USD ($) installment tranche $ / shares shares	Sep. 30, 2022 USD ($)	Jul. 31, 2020 USD ($)	Mar. 30, 2020 USD ($) shares
Debt Instrument [Line Items]
Unamortized debt discount			$ 78
Term Loans
Debt Instrument [Line Items]
Debt instrument, total discount recorded					$ 812
Term Loans | Term Loans, Tranche One | Common Stock Warrant
Debt Instrument [Line Items]
Fair value of warrant		$ 60
Term Loans | Term Loans, Tranche Two | Common Stock Warrant
Debt Instrument [Line Items]
Fair value of warrant					$ 60
Silicon Valley Bank | Original Agreement
Debt Instrument [Line Items]
Repayments of debt		3,000
Prepayment fee (equal to)		75
Silicon Valley Bank | Term Loans
Debt Instrument [Line Items]
Maximum borrowing capacity, amount		$ 15,000
Number of tranches (up to) | tranche		3
Debt instrument variable interest rate (as a percent)		0.25%
Percentage of default interest rate (as a percent)		4.00%
New capital milestone for continuation of interest only payment period		$ 40,000
Number of equal monthly installments payable | installment		25
Final payment percentage (as a percent)		5.50%
Silicon Valley Bank | Term Loans | Common Stock Warrant
Debt Instrument [Line Items]
Warrants issued (in shares) | shares		52,083
Warrants issued, exercise price (in dollars per share) | $ / shares		$ 4.32
Number of shares exercisable (in shares) | shares		17,361			17,361
Silicon Valley Bank | Term Loans | Base Rate
Debt Instrument [Line Items]
Debt instrument, interest rate floor (as a percent)		5.75%
Silicon Valley Bank | Term Loans | Term Loans, Tranche One
Debt Instrument [Line Items]
Proceeds from borrowings, net of issuance costs		$ 5,000
Silicon Valley Bank | Term Loans | Term Loans, Tranche Two
Debt Instrument [Line Items]
Proceeds from borrowings, net of issuance costs	$ 5,000
Silicon Valley Bank | Term Loans | Term Loans, Tranche Three
Debt Instrument [Line Items]
Unused borrowing capacity, expired amount				$ 5,000

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Long-term Debt - Schedule of Maturities of Long-term Debt (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Debt Disclosure [Abstract]
2022 (remainder of year)	$ 1,200
2023	2,800
Total future principal payments	$ 4,000

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Contingencies (Details) $ in Millions	3 Months Ended
	Jun. 30, 2022 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Current tax expense	$ 1.3

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License and Collaboration Agreements - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended		38 Months Ended	41 Months Ended
	Dec. 31, 2021 USD ($) program candidate $ / shares shares	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2020 USD ($) payment	Jun. 30, 2019 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities	$ 102,603	$ 77,013			$ 77,013
Revenue recognized from contract with customer		26,300	$ 18,900
AbbVie | Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential future revenue recognition, milestone method, number of payments | payment							1
Potential cash payment upon exercising license option							$ 75,000
Potential cash payment upon achievement of certain development and commercial milestones							205,000
Potential cash payment upon achievement of certain sales-based cash milestones							450,000
AbbVie | Product | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential future revenue recognition milestones receivable							75,000
AbbVie | Product | Upfront License Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities							$ 60,000
AbbVie | Product | Achieved Milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities	$ 45,000
Horizon
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of preclinical candidates | candidate	4
Number of existing programs | program	1
Number of additional programs | program	3
Horizon | Common Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of stock, premium on price per share, stock price period	30 days
Horizon | Private Placement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of shares issued in transaction (in shares) | shares	951,980
Purchase price per share (in dollars per share) | $ / shares	$ 15.76
Sale of stock, consideration received on transaction	$ 15,000
Sale of stock, premium on price per share, stock price period	25.00%
Sale of stock, consideration received on transaction, fair value portion	$ 11,900
Sale of stock, consideration received on transaction, additional consideration portion	3,100
Horizon | Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities	28,100
Potential future revenue recognition milestones receivable	1,500,000
Potential future revenue recognition milestones receivable, per program	381,000
Horizon | Product | Upfront Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities	25,000					$ 25,000
Horizon | Product | Premium Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities	$ 3,100
Horizon | Product | Research and Development
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized from contract with customer		446
Adaptimmune | Product | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential future milestones receivable (up to)		$ 288,000			288,000
Adaptimmune | Product | Upfront License Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities								$ 2,000
Adaptimmune | Product | License Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized from contract with customer					$ 3,000
Adaptimmune | Product | License Fee and Research Support Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract liabilities				$ 1,000
Adaptimmune | Product | Research Support Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized from contract with customer				$ 1,900

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License and Collaboration Agreements - Contract Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Contract Assets	$ 382	$ 25,000
Contract Liabilities	$ 77,013	$ 102,603

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License and Collaboration Agreements - Collaboration Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue	$ 8,367	$ 8,516	$ 27,288	$ 18,913
AbbVie
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue	6,632	8,516	17,155	18,913
Horizon
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue	1,279	0	9,535	0
Adaptimmune
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue	$ 456	$ 0	$ 598	$ 0

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Stockholders’ Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended		9 Months Ended
	Oct. 04, 2022	Jan. 01, 2022	Sep. 30, 2022	Jul. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Proceeds from issuance of common stock					$ 94,004	$ 90,812
Proceeds from exercise of stock options					742	$ 279
Deferred financing			$ 0		$ 0		$ 352
Options, grants in period (in shares)					1,891,150
Grants in period, weighted average exercise price (in dollars per share)					$ 10.99
Restricted Stock Units (RSUs)
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Awards granted during period (in shares)					3,750
Weighted average grant date fair value of awards granted during period (in dollars per share)					$ 9.00
Financing Agreements | Cowen
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Number of shares issued in transaction (in shares)					0
Maximum amount of common stock eligible to be sold (up to)				$ 75,000
Deferred financing			$ 488		$ 488
2018 Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Number of additional shares authorized (in shares)		1,500,000
Public Stock Offering
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Number of shares issued in transaction (in shares)			13,606,000
Net proceeds from public offering			$ 93,500
Legal and professional fees			550		$ 550
Proceeds from issuance of common stock			$ 94,000
Public Stock Offering | Subsequent Event
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Number of shares issued in transaction (in shares)	1,903,282
Proceeds from exercise of stock options	$ 13,100

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Stockholders’ Equity - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Class of Stock [Line Items]
Total stock-based compensation expense	$ 2,555	$ 1,638	$ 7,179	$ 4,780
Research and development
Class of Stock [Line Items]
Total stock-based compensation expense	1,558	936	4,212	2,596
General and administrative
Class of Stock [Line Items]
Total stock-based compensation expense	$ 997	$ 702	$ 2,967	$ 2,184

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Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Effective tax rate (as a percent)		4.82%	0.61%
Current tax expense	$ 1,300
Deferred tax expense	$ 100	$ 113	$ (61)
Current domestic federal income tax liabilities		$ 400