Gossamer Bio, Inc. 10-K

Item 9A. Controls and Procedures. Conclusion Regarding the Effectiveness of Disclosure Controls and Procedures We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in our periodic and current reports that we file with the SEC is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including our principal executive officer and principal financial officer, as appropriate, to allow timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognized that any controls and procedures, no matter how well designed and operated, can provide only reasonable and not absolute assurance of achieving the desired control objectives. In reaching a reasonable level of assurance, management necessarily was required to apply its judgment in evaluating the cost-benefit relationship of possible controls and procedures. In addition, the design of any system of controls also is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions; over time, control may become inadequate because of changes in conditions, or the degree of compliance with policies or procedures may deteriorate. Because of the inherent limitations in a cost-effective control system, misstatements due to error or fraud may occur and not be detected. Our management, with the participation of our principal executive officer and principal financial officer, has evaluated the effectiveness of our disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) under the 91 Table of Contents Exchange Act as of the end of the period covered by this annual report. Based on such evaluation, our principal executive officer and principal financial officer have concluded that as of such date, our disclosure controls and procedures were effective at the reasonable assurance level. Changes in Internal Control Over Financial Reporting There have been no changes in our internal control over financial reporting during the quarter ended December 31, 2025 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. Management’s Annual Report on Internal Control Over Financial Reporting Our management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act. Our internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, 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. Our management assessed the effectiveness of our internal control over financial reporting as of December 31, 2025 based on the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission in its 2013 Internal Control — Integrated Framework. Based on this assessment, our management has concluded that our internal control over financial reporting was effective as of December 31, 2025. Item 9B. Other Information. During the three months ended December 31, 2025, none of our officers or directors adopted or terminated any contract, instruction or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any “non Rule 10b5-1 trading arrangement," except as described below: • On October 31, 2025 , Faheem Hasnain , CEO and President , adopted a Rule 10b5-1 trading arrangement providing for the sale of up to 1,125,000 shares of our common stock. The trading arrangement is intended to satisfy the affirmative defense in Rule 10b5-1(c). The duration of the trading arrangement is from March 15, 2026 until December 29, 2026 , or earlier if and when all transactions under the trading arrangement are completed. On March 16, 2026, we commenced a workforce reduction of 77 individuals, constituting approximately 48% of our workforce, to reduce our operating expenses. Our remaining management and employees will continue the development of seralutinib and explore potential regulatory paths forward. This workforce reduction is expected to be substantially completed by the end of May 2026. In connection with the workforce reduction, on March 15, 2026, Richard Aranda, M.D., resigned from his position as the Chief Medical Officer of the Company effective as of April 15, 2026. The Company expects to execute a separation agreement with Dr. Aranda in connection with his departure, pursuant to which he will receive the severance provided under his employment agreement, in exchange for a general release of claims. Dr. Aranda will continue as a consultant to the Company to assist with transitional matters. We currently estimate that we will incur charges associated with the workforce reduction of approximately $6.7 million primarily related to employee severance payments, benefits and related termination costs. We expect the majority of related charges to be recognized in the second and third quarters of 2026. The estimates of the charges and expenditures that we expect to incur in connection with the workforce reduction, and the timing thereof, are subject to several assumptions and the actual amounts incurred may differ materially from these estimates. In addition, we may incur other charges or cash expenditures not currently contemplated due to unanticipated events that may occur, including in connection with the implementation of the workforce reduction. Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections. Not applicable. 92 Table of Contents PART III Item 10. Directors, Executive Officers and Corporate Governance. The information required by this item will be contained in our definitive proxy statement to be filed with the Securities and Exchange Commission in connection with our 2026 Annual Meeting of Stockholders, or the Definitive Proxy Statement, which is expected to be filed not later than 120 days after the end of our fiscal year ended December 31, 2025, under the headings “Election of Directors,” “Corporate Governance,” “Our Executive Officers,” and, if applicable, “Delinquent Section 16(a) Reports,” and is incorporated herein by reference. Code of Business Conduct and Ethics We have adopted a Code of Business Conduct and Ethics that applies to our officers, directors and employees, which is available on our website at www.gossamerbio.com. The Code of Business Conduct and Ethics contains general guidelines for conducting the business of our company consistent with the highest standards of business ethics and is intended to qualify as a “code of ethics” within the meaning of Section 406 of the Sarbanes-Oxley Act of 2002 and Item 406 of Regulation S-K. In addition, we intend to promptly disclose (1) the nature of any amendment to our Code of Business Conduct and Ethics that applies to our principal executive officer, principal financial officer, principal accounting officer or controller or persons performing similar functions and (2) the nature of any waiver, including an implicit waiver, from a provision of our code of ethics that is granted to one of these specified officers, the name of such person who is granted the waiver and the date of the waiver on our website in the future. Information contained in our website does not constitute a part of this report or our other filings with the SEC. Insider Trading Policy We have adopted a policy on insider trading and procedures that govern the purchase, sale, and/or other dispositions of our securities by our directors, officers, employees and other covered persons that are designed to promote compliance with insider trading laws, rules and regulations, and the Nasdaq listing rules, as applicable. A copy of our policy on insider trading is filed as Exhibit 19.1 to this annual report on Form 10-K. It is our policy to comply with U.S. insider trading laws and regulations, including with respect to transactions in our own securities. Item 11. Executive Compensation. The information required by this item will be set forth in the section headed “Executive Compensation and Other Information” in our Definitive Proxy Statement and is incorporated herein by reference. Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters. The information required by this item will be set forth in the section headed “Security Ownership of Certain Beneficial Owners and Management” in our Definitive Proxy Statement and is incorporated herein by reference. The information required by Item 201(d) of Regulation S-K will be set forth in the section headed "Executive Compensation and Other Information" in our Proxy Statement and is incorporated herein by reference. Item 13. Certain Relationships and Related Transactions, and Director Independence. The information required by this item will be set forth in the section headed “Certain Relationships and Related Person Transactions,” “Board Independence” and “Board Committees and Independence” in our Definitive Proxy Statement and is incorporated herein by reference. Item 14. Principal Accounting Fees and Services. The information required by this item will be set forth in the section headed “Independent Registered Public Accounting Firm's Fees” in our Definitive Proxy Statement and is incorporated herein by reference. 93 Table of Contents PART IV Item 15. Exhibits, Financial Statement Schedules. (1) All Financial statements The consolidated financial statements of Gossamer Bio, Inc., together with the report thereon of Ernst & Young LLP, an independent registered public accounting firm, are included in this annual report on Form 10-K beginning on page F-1. (2) Financial statement schedules All schedules have been omitted because the information required to be set forth therein is not applicable or is shown in the consolidated financial statements or notes thereto. (3) Exhibits A list of exhibits is set form on the Exhibit Index immediately preceding the signature page of this annual report on Form 10-K and is incorporated herein by reference. Item 16. Form 10–K Summary. None. 94 Table of Contents Gossamer Bio, Inc. Index to Consolidated Financial Statements Page Report of Independent Registered Public Accounting Firm ; Ernst & Young LLP, San Diego, CA (PCAOB ID: 42 ) F- 1 Consolidated Balance Sheets F- 3 Consolidated Statements of Operations and Comprehensive Loss F- 4 Consolidated Statements of Stockholders’ Equity (Deficit) F- 5 Consolidated Statements of Cash Flows F- 6 Notes to Consolidated Financial Statements F- 7 Table of Contents Report of Independent Registered Public Accounting Firm To the Stockholders and the Board of Directors of Gossamer Bio, Inc. Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of Gossamer Bio, Inc. (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations and comprehensive loss, stockholders' equity (deficit) and cash flows for each of the three years in the period ended December 31, 2025, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with U.S. generally accepted accounting principles. The Company's Ability to Continue as a Going Concern The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As discussed in Note 1 to the financial statements, the Company has suffered recurring losses from operations and has stated that substantial doubt exists about the Company’s ability to continue as a going concern. Management's evaluation of the events and conditions and management’s plans regarding these matters are also described in Note 1. The consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Basis for Opinion These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion. Critical audit matter The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the account or disclosure to which it relates. F-1 Table of Contents Accrued research and development expenses Description of the matter As of December 31, 2025, the Company accrued $21.7 million for research and development expenses. As described in Note 2 of the consolidated financial statements, the Company records accruals for estimated research and development costs, comprising payments due for work performed by third party contractors, laboratories, participating clinical trial sites, and others. Some of these contractors bill monthly based on actual services performed, while others bill periodically based upon achieving certain contractual milestones. For the latter, the Company accrues the expenses as goods or services are used or rendered. Clinical trial site costs are accrued as patients enter and progress through the trial. Auditing management’s accounting for accrued research and development expenses is especially challenging as evaluating the progress or stage of completion of the activities under the Company’s research and development agreements is dependent upon a high volume of data from third-party service providers and internal clinical personnel, which is tracked in spreadsheets and other end user computing programs. How we addressed the matter in our audit To test the completeness of the Company’s accrued research and development expenses, among other procedures, we obtained supporting evidence of the research and development activities performed for significant clinical trials. We corroborated the status of significant research and development activities through meetings with accounting and clinical project managers. To verify the appropriate measurement of accrued research and development costs, we compared the costs for a sample of transactions against the related invoices and contracts, and confirmed amounts incurred to-date with third-party service providers. We also examined a sample of subsequent payments to evaluate the completeness of the accrued research and development expenses. /s/ Ernst & Young LLP We have served as the Company’s auditor since 2018. San Diego, California March 17, 2026 F-2 Table of Contents GOSSAMER BIO, INC. Consolidated Balance Sheets (in thousands, except share and par value amounts) December 31, 2025 2024 ASSETS Current assets Cash and cash equivalents $ 37,732 $ 46,074 Marketable securities 99,200 248,444 Receivable from contracts with collaborators 12,227 5,338 Prepaid expenses and other current assets 18,485 10,032 Total current assets 167,644 309,888 Property and equipment, net 64 10 Operating lease right-of-use assets 4,133 5,111 Other assets 408 283 Total assets $ 172,249 $ 315,292 LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT) Current liabilities Accounts payable $ 5,959 $ 2,319 Accrued research and development expenses 21,662 10,455 Current contract liabilities 19,987 17,050 Accrued expenses and other current liabilities 15,827 15,186 Total current liabilities 63,435 45,010 Long-term convertible senior notes 198,508 197,523 Operating lease liabilities - long-term 3,460 4,398 Long-term contract liabilities 29,606 38,869 Total liabilities 295,009 285,800 Commitments and contingencies (Note 11) Stockholders' equity (deficit) Common stock, $ 0.0001 par value; 700,000,000 shares authorized as of December 31, 2025 and December 31, 2024; 233,677,057 shares issued and outstanding as of December 31, 2025, and 226,604,138 shares issued and outstanding as of December 31, 2024 24 23 Additional paid-in capital 1,321,303 1,296,848 Accumulated deficit ( 1,438,938 ) ( 1,268,568 ) Accumulated other comprehensive income (loss) ( 5,149 ) 1,189 Total stockholders' equity (deficit) ( 122,760 ) 29,492 Total liabilities and stockholders' equity (deficit) $ 172,249 $ 315,292 The accompanying notes are an integral part of these consolidated financial statements. F-3 Table of Contents GOSSAMER BIO, INC. Consolidated Statements of Operations and Comprehensive Loss (in thousands, except share and per share amounts) Year Ended December 31, 2025 2024 2023 Revenue: Revenue from sale of licenses $ — $ 90,682 $ — Revenue from contracts with collaborators 48,471 24,019 — Total revenue 48,471 114,701 — Operating expenses: Research and development 174,093 138,487 135,304 In process research and development 7,475 — 10,000 General and administrative 37,631 36,133 38,455 Total operating expenses 219,199 174,620 183,759 Loss from operations ( 170,728 ) ( 59,919 ) ( 183,759 ) Other income (expense) Interest income 1,970 1,779 1,997 Interest expense ( 10,989 ) ( 11,517 ) ( 13,511 ) Other income, net 9,289 14,022 15,456 Total other income, net 270 4,284 3,942 Loss before provision (benefit) for income taxes ( 170,458 ) ( 55,635 ) ( 179,817 ) Provision (benefit) for income taxes ( 88 ) 893 — Net loss $ ( 170,370 ) $ ( 56,528 ) $ ( 179,817 ) Other comprehensive income (loss): Foreign currency translation ( 6,248 ) 1,450 33 Unrealized income (loss) on marketable securities ( 90 ) 89 191 Other comprehensive income (loss) ( 6,338 ) 1,539 224 Comprehensive loss $ ( 176,708 ) $ ( 54,989 ) $ ( 179,593 ) Net loss per share, basic and diluted $ ( 0.75 ) $ ( 0.25 ) $ ( 1.18 ) Weighted average common shares outstanding, basic and diluted 228,519,130 226,228,016 152,621,669 The accompanying notes are an integral part of these consolidated financial statements. F-4 Table of Contents GOSSAMER BIO, INC. Consolidated Statements of Stockholders’ Equity (Deficit) (in thousands, except share amounts) Common stock Additional paid-in capital Accumulated deficit Accumulated other comprehensive income (loss) Total stockholders' equity (deficit) Shares Amount Balance as of December 31, 2022 94,423,181 $ 10 $ 1,044,864 $ ( 1,032,223 ) $ ( 574 ) $ 12,077 Issuance of common stock in connection with a private offering, net of offering costs of $ 10,779 129,869,440 13 201,310 — — 201,323 Vesting of restricted stock 55,225 — — — — — Stock-based compensation — — 28,518 — — 28,518 Issuance of common stock pursuant to Employee Stock Purchase Plan 336,795 — 444 — — 444 Issuance of common stock for restricted stock units vested 724,674 — — — — — Net loss — — — ( 179,817 ) — ( 179,817 ) Other comprehensive income — — — — 224 224 Balance as of December 31, 2023 225,409,315 $ 23 $ 1,275,136 $ ( 1,212,040 ) $ ( 350 ) $ 62,769 Grant of equity option pursuant to Chiesi Collaboration Agreement — — 464 — — 464 Stock-based compensation — — 20,619 — — 20,619 Issuance of common stock pursuant to Employee Stock Purchase Plan 767,125 — 629 — — 629 Issuance of common stock for restricted stock units vested 427,698 — — — — — Net loss — — — ( 56,528 ) — ( 56,528 ) Other comprehensive income — — — — 1,539 1,539 Balance as of December 31, 2024 226,604,138 $ 23 $ 1,296,848 $ ( 1,268,568 ) $ 1,189 $ 29,492 Investment in merger option through issuance of stock 2,500,000 1 7,475 — — 7,476 Exercise of warrants 1,791,823 — 3,655 — — 3,655 Exercise of stock options 1,691,213 — 1,930 — — 1,930 Stock-based compensation — — 10,555 — — 10,555 Issuance of common stock pursuant to Employee Stock Purchase Plan 1,089,883 — 840 — — 840 Net loss — — — ( 170,370 ) — ( 170,370 ) Other comprehensive loss — — — — ( 6,338 ) ( 6,338 ) Balance as of December 31, 2025 233,677,057 $ 24 $ 1,321,303 $ ( 1,438,938 ) $ ( 5,149 ) $ ( 122,760 ) The accompanying notes are an integral part of these consolidated financial statements. F-5 Table of Contents GOSSAMER BIO, INC. Consolidated Statements of Cash Flows (in thousands) Year Ended December 31, 2025 2024 2023 Cash flows from operating activities Net loss $ ( 170,370 ) $ ( 56,528 ) $ ( 179,817 ) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 24 833 1,607 Stock-based compensation expense 10,555 20,619 28,518 In process research and development expenses 7,475 — 10,000 Amortization of operating lease right-of-use assets 978 3,318 2,778 Amortization of long-term debt discount and issuance costs 985 1,086 1,321 Amortization of premium on investments, net of accretion of discounts ( 7,278 ) ( 13,062 ) ( 9,450 ) Net realized gain on investments ( 5 ) — — Loss on disposal of property and equipment — 806 726 Changes in operating assets and liabilities: Receivable from contracts with collaborators ( 6,889 ) ( 5,338 ) — Prepaid expenses and other current assets ( 8,453 ) 62 ( 3,892 ) Other assets ( 125 ) 335 62 Operating lease liabilities ( 961 ) ( 3,386 ) ( 2,982 ) Accounts payable ( 2,747 ) ( 1,656 ) 3,990 Accrued expenses 1,448 ( 10,718 ) ( 835 ) Accrued research and development expenses 11,207 2,676 ( 7,847 ) Accrued compensation and benefits ( 784 ) 1,701 ( 3,240 ) Contract liabilities ( 6,326 ) 55,919 — Accrued interest expense — ( 135 ) ( 97 ) Net cash used in operating activities ( 171,266 ) ( 3,468 ) ( 159,158 ) Cash flows from investing activities Purchase of marketable securities ( 227,107 ) ( 494,777 ) ( 441,670 ) Maturities of marketable securities 376,400 523,800 330,700 Sales of marketable securities 7,144 — — Purchase of property and equipment ( 79 ) — — Net cash provided by (used in) investing activities 156,358 29,023 ( 110,970 ) Cash flows from financing activities Proceeds from issuance of common stock and warrants in a private offering, net of offering costs — — 201,323 Proceeds from issuance of common stock under Employee Stock Purchase Plan 840 629 444 Proceeds from the exercise of stock options 1,930 — — Proceeds from the exercise of warrants 3,655 — — Proceeds from issuance of equity option pursuant to stock purchase agreement — 464 — Principal repayments of long-term debt — ( 12,581 ) ( 11,613 ) Net cash provided by (used in) financing activities 6,425 ( 11,488 ) 190,154 Effect of exchange rate changes on cash and cash equivalents 141 ( 102 ) 110 Net increase (decrease) in cash and cash equivalents ( 8,342 ) 13,965 ( 79,864 ) Cash and cash equivalents, at the beginning of the period 46,074 32,109 111,973 Cash and cash equivalents, at the end of the period $ 37,732 $ 46,074 $ 32,109 Supplemental disclosure of cash flow information: Cash paid for interest $ 10,000 $ 10,561 $ 12,288 Supplemental disclosure of noncash investing and financing activities: Right-of-use assets obtained in exchange for lease liabilities $ — $ 5,298 $ — Change in unrealized gain (loss) on marketable securities, net $ ( 90 ) $ 89 $ 191 The accompanying notes are an integral part of these consolidated financial statements. F-6 Table of Contents Gossamer Bio, Inc. Notes to Consolidated Financial Statements Note 1— Description of Business Gossamer Bio, Inc. (including its subsidiaries, referred to as "we," "us," "our,", or the “Company”) is a clinical-stage clinical biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary hypertension ("PH") including pulmonary arterial hypertension ("PAH") and PH associated with interstitial lung disease ("PH-ILD"). The Company was incorporated in the state of Delaware on October 25, 2015 (originally as FSG Bio, Inc.) and is based in San Diego, California. The consolidated financial statements include the accounts of Gossamer Bio, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions among the consolidated entity have been eliminated in consolidation. Liquidity and Going Concern The Company has incurred significant operating losses since its inception. As of December 31, 2025, the Company had an accumulated deficit of $ 1,438.9 million. From the Company’s inception through the year ended December 31, 2025, the Company has funded its operations primarily through equity financings, convertible senior notes and the Chiesi Collaboration Agreement (as defined in Note 12 below). The consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and settlement of liabilities, in the normal course of business, and does not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. If the Company is not able to obtain the required funding, through equity or debt financings, license agreements for seralutinib in domestic or foreign markets, or other means, or is unable to obtain funding on terms favorable to the Company, or there is an event of default affecting the Company’s 2027 Notes, there will be a material adverse effect on commercialization and development operations, and the Company's ability to execute its strategic development plan for future growth. If the Company cannot successfully raise additional funding and implement its strategic development plan, the Company may be forced to make further reductions in spending, including spending in connection with our clinical development, pre-commercialization activities, extend payment terms with suppliers, suspend or curtail planned operations or cease operations entirely. The Company has concluded that these circumstances and the uncertainties associated with the Company’s ability to obtain additional equity or debt financing on terms that are favorable to the Company, or at all, and otherwise succeed in its future operations raise substantial doubt about the Company’s ability to continue as a going concern. Management believes that it has sufficient working capital on hand to fund operations into the first quarter of 2027. Note 2— Summary of Significant Accounting Policies Basis of Presentation The Company’s consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The most significant estimates in the Company’s consolidated financial statements relate to accrued research and development expenses, stand-alone selling price of performance obligations and estimated collaboration expenses associated with the Company’s Chiesi Collaboration Agreement. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results could differ from those estimates. Segments Operating segments are identified as components of an enterprise about which discrete financial information is available for evaluation by the chief operating decision-maker ("CODM") in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment. The F-7 Table of Contents identification of a single operating and reportable segment is consistent with the management approach as the CODM regularly reviews consolidated financial information for the purpose of assessing performance and allocating resources. See Note 13. Segment Reporting to the consolidated financial statements. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. The carrying amounts reported in the consolidated balance sheets for cash and cash equivalents are valued at cost, which approximate their fair value. Marketable Securities The Company considers securities with original maturities of greater than three months to be marketable securities. The Company has the ability, if necessary, to liquidate any of its marketable securities to meet its liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as current assets on the accompanying consolidated balance sheets which reflects management’s intention to use the proceeds from sales of these securities to fund our operations, as necessary. The Company’s marketable securities consist of U.S. Treasury and agency securities, commercial paper and corporate debt securities. Marketable securities are recorded at fair value and unrealized gains and losses are recorded within accumulated other comprehensive loss. The estimated fair value of the marketable securities is determined based on quoted market prices or rates for similar instruments. The Company evaluates securities with unrealized losses to determine whether such losses, if any, are due to credit-related factors. The Company records an allowance for credit losses when unrealized losses are due to credit-related factors. Realized gains and losses are calculated using the specific identification method and recorded in other income, net in the Company's consolidated statements of operation and comprehensive loss. The Company does not generally intend to sell the investments and it is not more likely than not that it will be required to sell the investments before recovery of their amortized cost bases, which may be at maturity. The Company has determined that there were no material declines in fair values of its investments due to credit-related factors as of December 31, 2025. Concentrations of Credit Risk and Off-Balance Sheet Risk Cash, cash equivalents and marketable securities are financial instruments that are potentially subject to concentrations of credit risk. The Company’s cash and cash equivalents are deposited in accounts at large financial institutions, and amounts may exceed federally insured limits. The Company believes it is not exposed to significant credit risk due to the financial strength of the depository institutions in which the cash and cash equivalents are held. The Company maintains its cash equivalents in U.S. Treasury and agency securities and commercial paper with maturities less than three months and in money market funds that invest in U.S. Treasury and agency securities. The Company’s available for sale securities are also invested in U.S. Treasury and agency securities. The Company has not recognized any losses from credit risks on such accounts during any of the periods presented. The Company believes it is not exposed to significant credit risk on its cash, cash equivalents and available for sale securities. Property and Equipment, Net Property and equipment, net, which consists mainly of lab equipment and leasehold improvements, are carried at cost less accumulated depreciation. Depreciation is computed over the estimated useful lives of the respective assets, generally two to seven years , using the straight-line method. Convertible Senior Notes The Company accounts for the 2027 Notes as a liability measured at amortized cost. The carrying amount was calculated by measuring the fair value of similar debt instruments that do not have associated convertible features. The excess of the principal amount over its carrying amount (“debt discount”) is amortized to interest expense over the term of the 2027 Notes. Issuance costs were recorded as a reduction to the principal amount of the 2027 Notes and are being amortized to interest expense over the term of the 2027 Notes. Leases In accordance with Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842), the Company determines if an arrangement is a lease at inception. Operating leases are included in the balance sheet as right-of-use assets and operating lease liabilities at the present value of the lease payments calculated using the Company’s incremental borrowing rate, unless the implicit rate is readily available. The Company applied the short-term lease recognition exemption for leases with F-8 Table of Contents terms at inception not greater than 12 months and elected to not separate lease and non-lease components for its long-term leases. The Company records rent expense on a straight-line basis over the term of the lease. Research and Development All research and development costs are expensed as incurred. Research and development costs consist primarily of salaries, employee benefits, costs associated with preclinical studies and clinical trials (including amounts paid to clinical research organizations and other professional services). Payments made prior to the receipt of goods or services to be used in research and development are capitalized until the goods or services are received. The Company records accruals for estimated research and development costs, comprising payments for work performed by third party contractors, laboratories, participating clinical trial sites, and others. Some of these contractors bill monthly based on actual services performed, while others bill periodically based upon achieving certain contractual milestones. For the latter, the Company accrues the expenses as goods or services are used or rendered. Clinical trial site costs related to patient enrollment are accrued as patients enter and progress through the trial. Upfront costs, such as costs associated with setting up clinical trial sites for participation in the trials, are expensed immediately once incurred as research and development expenses. In process research and development In process research and development costs relate to a milestone payment to Pulmokine for the initiation of the Phase 3 clinical trial for seralutinib and acquisition of the Respira Merger Option. Patent Costs Costs related to filing and pursuing patent applications are expensed as incurred, as recoverability of such expenditures is uncertain. These costs are included in general and administrative expenses. Income Taxes Income taxes are recorded in accordance with Financial Accounting Standards Board (“FASB”) ASC 740, Income Taxes , which provides for deferred taxes using an asset and liability approach. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are provided, if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company does not recognize any deferred taxes related to the U.S. taxes on foreign earnings as we recognize these taxes as a period cost. The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit would more likely than not be realized assuming examination by the taxing authority. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company's policy is to include interest and penalties related to income taxes within its provision (benefit) for income taxes. The Company is subject to taxation in the United States, California, Florida, Ireland and Luxembourg. As of December 31, 2025, the Company’s tax years since inception are subject to examination by taxing authorities due to the Company’s unutilized net operating losses ("NOLs") and tax credits. Collaborative Arrangements The Company assesses whether its licensing and other agreements are collaborative arrangements based on whether they involve joint operating activities and whether both parties have active participation in the arrangement and are exposed to significant risks and rewards. For arrangements that the Company determines are collaborations, it identifies each unit of account, and then determines whether a customer relationship exists for that unit of account. If the Company determines a performance obligation within the collaborative arrangement to be with a customer, it applies its revenue recognition accounting policy. If a portion of a distinct bundle of goods or services within the collaborative arrangement is not with a customer, the Company applies recognition and measurement based on an analogy to authoritative accounting literature or, if there is no appropriate analogy, a reasonable, rational and consistently applied accounting policy election. To the extent the arrangement is within the scope of ASC 808, the Company assesses whether aspects of the arrangement between the Company F-9 Table of Contents and the collaboration partner are within the scope of other accounting literature. If the Company concludes that some or all aspects of the arrangement represent a transaction with a customer, the Company accounts for those aspects of the arrangement within the scope of ASC Topic 606, Revenue from Contracts with Customers (ASC 606). See Note 12, "Significant Agreements and Contracts," for more information. Revenue Recognition The Company recognizes revenue when a customer obtains control of promised goods or services in a contract for an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. For contracts with customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. As part of the accounting for contracts with customers, the Company develops assumptions that require judgment to determine the standalone selling price of each distinct performance obligation identified in the contract. In addition, variable consideration such as milestone payments are evaluated to determine if they are constrained and, therefore, excluded from the transaction price. The Company then allocates the total transaction price proportionally to each distinct performance obligation based on their estimated standalone selling prices, unless an allocation exception applies. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective distinct performance obligation when (or as) the performance obligation is satisfied. In a contract with multiple performance obligations, the Company must develop estimates and assumptions that require judgment to determine the underlying standalone selling price for each distinct performance obligation, which determines how the transaction price is allocated among the distinct performance obligations. The estimation of the stand-alone selling price(s) may include estimates regarding forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time. Any change made to estimated progress towards completion of a distinct performance obligation and, therefore, revenue recognized will be recorded as a change in estimate. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in a contract, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from the allocated transaction price. The Company evaluates the measure of progress at each reporting period and, if necessary, adjusts the measure of performance and related revenue or expense recognition as a change in estimate. At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being reached. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or a collaboration partner’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of milestones that are within its or a collaboration partner’s control, such as operational developmental milestones and any related constraint, and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which will affect revenue from sale of licenses and revenue from contracts with collaborators in the period of adjustment. Revisions to the Company’s estimate of the transaction price may also result in negative revenue from sale of licenses and revenue from contracts with collaborators in the period of adjustment. For arrangements that include sales-based royalties, including commercial milestone payments based on the level of sales, and a license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied, or partially satisfied. To date, the Company has not recognized any royalty revenue from collaborative arrangements. For arrangements that include cost-share reimbursements, we will recognize such payments when control of the related goods or services are transferred to the customer. Cost-sharing reimbursements are presented as revenue from contracts with collaborators. F-10 Table of Contents Stock-Based Compensation The Company expenses stock-based compensation to employees and non-employees over the requisite service period based on the estimated grant-date fair value of the awards. The Company records the expense for stock-based compensation awards subject to performance-based milestone vesting over the requisite service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the expected satisfaction of the performance conditions at each reporting date. The Company estimates the fair value of stock option grants and shares purchasable under the Company's 2019 Employee Stock Purchase Plan ("ESPP") using the Black-Scholes option pricing model, and the assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. The Company estimates the fair value of restricted stock units based on the closing price of the Company's common stock on the date of grant. The Company accounts for forfeitures as they occur. All share-based compensation costs are recorded in the statements of operations based upon the underlying employees or non-employee’s roles within the Company. Foreign Currency Assets and liabilities of non-U.S. subsidiaries that operate in a local currency environment, where that local currency is the functional currency, are translated to U.S. dollars at exchange rates in effect at the balance sheet date. Income and expense accounts are translated at average exchange rates during the year which approximate the rates in effect at the transaction dates. The resulting translation adjustments are recorded in accumulated other comprehensive income (loss) in the Company's consolidated balance sheets. Foreign exchange transaction gains and losses are included in other income, net in the Company’s consolidated statement of operations and comprehensive loss. Recent Accounting Pronouncements - Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures (“Topic 280”), which modifies the disclosure and presentation requirements of reportable segments. The amendments in the update require the disclosure of significant segment expenses that are regularly provided to the Chief Operating Decision Maker ("CODM") and included within each reported measure of segment profit and loss. The amendments also require disclosure of all other segment items by reportable segment and a description of its composition. Additionally, the amendments require disclosure of the title and position of the CODM and an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. Lastly, the amendment requires that a public entity that has a single reportable segment provide all the disclosures required by ASU 2023-07 and all existing segment disclosures in Topic 280. This update is effective for annual periods beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. We have adopted this standard for our fiscal year ended December 31, 2024. We have applied this standard retrospectively for all prior periods presented in the financial statements. There was no impact on our reportable segments identified and additional required disclosures have been included in Note 13, Segment Reporting. In December 2023, the FASB issued ASU 2023-09 Income Taxes (Topics 740): Improvements to Income Tax Disclosures, to expand the disclosure requirements for income taxes, specifically related to the rate reconciliation and income taxes paid. ASU 2023-09 is effective for our annual periods beginning January 1, 2025, with early adoption permitted. We have adopted this standard for our fiscal year ended December 31, 2025 on a retrospective basis, and the adoption did not have a material impact on our consolidated financial statements and related disclosures. See Note 7, Income Taxes, to the consolidated financial statements. Recent Accounting Pronouncements - Not Yet Adopted In November 2024, the FASB issued ASU No. 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, as further clarified by ASU 2025-01, Income Statement - Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date, issued in January, 2025, which requires disaggregated disclosure of certain costs and expenses on an interim and annual basis. ASU No. 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. The disclosure updates are required to be applied prospectively with the option for retrospective application. The Company is currently evaluating the impact of adopting ASU No. 2024-03. In December 2025, the FASB issued ASU No. 2025-12, Codification Improvements, to address suggestions received from stakeholders on the ASC and to make other incremental improvements to U.S. GAAP. The update represents F-11 Table of Contents changes to the ASC that clarify, correct errors in or make other improvements to a variety of topics that are intended to make it easier to understand and apply. ASU No. 2025-12 is effective for fiscal years beginning after December 15, 2026 and interim periods. The Company is currently evaluating the impact of adopting ASU No. 2024-12 on its consolidated financial statements and related disclosures. In December 2025, the FASB issued ASU No. 2025-11, Interim Reporting (Topic 270), which provides clarifications intended to improve the consistency and usability of interim disclosure requirements, including a comprehensive listing of required interim disclosures and a new disclosure principle for reporting material events occurring after the most recent annual period. The amendments do not change the underlying objectives of interim reporting but are designed to enhance clarity in application. ASU No. 2025-11 is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years. The Company is currently evaluating the impact of adopting ASU No. 2024-11 on its consolidated financial statements and related disclosures. Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not, or are not believed by management to, have a material impact on the Company’s present or future financial position, results of operations, cash flows or disclosures. Net Loss Per Share Basic net loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. The Company uses the if-converted method for assumed conversion of the 2027 Notes to compute the weighted average shares of common stock outstanding for diluted net loss per share. Diluted net loss per share excludes the potential impact of the Company’s common stock options, warrants for the purchase of common stock, unvested shares of restricted stock and the potential shares issuable upon conversion of the 2027 Notes because their effect would be anti-dilutive due to the Company’s net loss. Since the Company had a net loss in each of the periods presented, basic and diluted net loss per common share are the same because the otherwise dilutive potential common shares become anti-dilutive and are therefore excluded. The table below provides potentially dilutive securities not included in the calculation of the diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares): December 31, 2025 2024 2023 2027 Notes 12,321,900 12,321,900 12,321,900 Shares issuable upon exercise of stock options 47,436,953 34,416,337 23,626,115 Shares issuable upon exercise of Chiesi Equity Option — 22,433,809 — Shares issuable upon exercise of warrants 30,675,537 32,467,360 32,467,360 Nonvested shares under performance stock units 4,126,962 — — Nonvested shares under restricted stock grants — — 427,698 Total potentially dilutive securities 94,561,352 101,639,406 68,843,073 Note 3— Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): F-12 Table of Contents December 31, 2025 2024 Accrued compensation and benefits $ 11,211 $ 11,995 Operating lease liabilities 938 961 Accrued consulting fees 1,807 841 Accrued interest 833 833 Accrued legal fees 84 65 Accrued accounting fees 449 180 Accrued other 499 311 Accrued income tax 6 — Total accrued expenses and other current liabilities $ 15,827 $ 15,186 Note 4— Fair Value Measurements and Available for Sale Investments Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets; Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The Company classifies its cash equivalents and available-for-sale investments within Level 1 or Level 2. The fair value of the Company’s investment grade corporate debt securities and commercial paper classified as Level 2 is determined using proprietary valuation models and analytical tools, which utilize market pricing or prices for similar instruments that are both objective and publicly available, such as matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, and offers. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents the hierarchy for assets measured at fair value on a recurring basis as of December 31, 2025 and 2024 (in thousands): F-13 Table of Contents Fair Value Measurements at End of Period Using: Total Fair Value Quoted Market Prices for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) As of December 31, 2025 Money market funds $ 22,228 $ 22,228 $ — $ — U.S. Treasury and agency securities 8,090 8,090 — — Commercial paper 73,592 — 73,592 — Corporate debt securities 27,377 — 27,377 — As of December 31, 2024 Money market funds $ 25,264 $ 25,264 $ — $ — U.S. Treasury and agency securities 56,900 56,900 — — Commercial paper 188,653 — 188,653 — Corporate debt securities 19,963 — 19,963 — The Company did not reclassify any investments between levels in the fair value hierarchy during the periods presented. Fair Value of Other Financial Instruments As of December 31, 2025 and 2024, the carrying amounts of the Company’s financial instruments, which include cash, prepaid and other current assets, interest receivable, accrued research and development expenses, accounts payable and accrued expenses and other current liabilities, approximate fair values because of their short-term maturities. As of December 31, 2025 and 2024, the interest receivable was $ 0.3 million and $ 0.2 million, respectively. Interest receivable is recorded as a component of prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2025 and 2024 the fair value of the Company's 2027 Notes was $ 138.3 million and $ 110.0 million, respectively. The fair value was determined on the basis of market prices observable for similar instruments and is considered Level 2 in the fair value hierarchy (see Note 5). Available for Sale Investments The Company invests its excess cash in U.S. Treasury and agency securities, corporate debt securities, and commercial paper, which are classified as available-for-sale investments. These investments are carried at fair value and are included in the tables below. The Company evaluates securities with unrealized losses to determine whether such losses, if any, are due to credit-related factors. Realized gains and losses are calculated using the specific identification method and recorded in other income, net in the Company's consolidated statements of operations and comprehensive loss. The Company has classified these investments as available-for-sale, as the sale of such investments may be required prior to maturity to implement management strategies, and therefore has classified all investment securities as current assets. F-14 Table of Contents The aggregate market value, cost basis, and gross unrealized gains and losses of available-for-sale investments by security type, classified in marketable securities as of December 31, 2025 and 2024 are as follows (in thousands except securities amounts): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Total Fair Value As of December 31, 2025 U.S Treasury and agency securities $ 8,088 $ 2 $ — $ 8,090 Corporate debt securities 27,359 18 — 27,377 Commercial paper 73,544 49 ( 1 ) 73,592 Total marketable securities $ 108,991 $ 69 $ ( 1 ) $ 109,059 Number of securities with unrealized losses 1 As of December 31, 2024 U.S. Treasury and agency securities $ 56,875 $ 25 $ — $ 56,900 Corporate debt securities 19,950 $ 13 — 19,963 Commercial paper 188,537 142 ( 26 ) 188,653 Total marketable securities $ 265,362 $ 180 $ ( 26 ) $ 265,516 Number of securities with unrealized losses 5 As of December 31, 2025 and 2024, the Company classified $ 22.2 million and $ 25.3 million, respectively, of assets with original maturities of three months or less as cash and cash equivalents. At each reporting date, the Company performs an evaluation of impairment to determine if any unrealized losses are due to credit-related factors. The Company records an allowance for credit losses when unrealized losses are due to credit-related factors. Factors considered when evaluating available-for-sale investments for impairment include the severity of the impairment, changes in underlying credit ratings, the financial condition of the issuer, the probability that the scheduled cash payments will continue to be made and the Company’s intent and ability to hold the investment until recovery of the amortized cost basis. The Company does not intend to sell these debt securities that are in an unrealized loss position, and it is not more likely than not that the Company will be required to sell these debt securities before recovery of their amortized cost bases, which may be at maturity. Based on the credit quality of the debt securities, and the Company’s estimates of future cash flows to be collected from those securities, the Company believes the unrealized losses are not credit losses. As of December 31, 2025 and 2024, there were no material declines in the market value of the Company's available-for-sale investments due to credit-related factors. Contractual maturities of available-for-sale debt securities, as of December 31, 2025, were as follows (in thousands): Estimated Fair Value Less than one year $ 109,059 Greater than one year — Total $ 109,059 The Company has the ability, if necessary, to liquidate any of its cash equivalents and marketable securities to meet its liquidity needs in the next 12 months. Note 5— Indebtedness Credit Facility On May 2, 2019, the Company entered into a credit, guaranty and security agreement, as amended on September 18, 2019, July 2, 2020, December 7, 2022 and February 14, 2023 (the “Credit Facility”), with MidCap Financial Trust (“MidCap”), as agent and lender, and the additional lenders party thereto from time to time (together with MidCap, the “Lenders”), pursuant to which the Lenders, agreed to make term loans available to the Company for working capital and general business purposes, in a principal amount of up to $ 150.0 million in term loan commitments, including a $ 30.0 million term loan that was funded at the closing date, with the ability to access the remaining $ 120.0 million in two additional tranches F-15 Table of Contents (each $ 60.0 million), subject to specified availability periods, the achievement of certain clinical development milestones, minimum cash requirements and other customary conditions. On May 3, 2024, the Credit Facility was terminated and the Company recorded a $ 7.7 million payment of the outstanding debt balance in full and discharged, which released the Company from the obligations under the Credit Facility, and Lenders’ security interests in the Company’s assets and property were released. Unamortized debt discount and issuance costs were written off and recorded in interest expense on the consolidated statements of operations and comprehensive loss. As of December 31, 2025, the Company has no further obligations under the Credit Facility. 5.00 % Convertible Senior Notes due 2027 On May 21, 2020, the Company issued $ 200.0 million aggregate principal amount of 5.00 % convertible senior notes due 2027 in a public offering (the "2027 Notes"). The 2027 Notes were registered pursuant to the Company’s shelf registration statement on Form S-3 filed with the SEC on April 10, 2020. The interest rate on the 2027 Notes is fixed at 5.00 % per annum. Interest is payable semi-annually in arrears on June 1 and December 1 of each year, commencing on December 1, 2020. The 2027 Notes will mature on June 1, 2027. The net proceeds from the offering, after deducting the underwriting discounts and commissions and other offering costs, were approximately $ 193.6 million. The 2027 Notes may be settled in cash, shares of the Company’s common stock, or a combination thereof, solely at the Company’s election. The initial conversion rate of the 2027 Notes is 61.6095 shares per $1,000 principal amount, which is equivalent to a conversion price of approximately $ 16.23 per share, subject to adjustments. In addition, following certain corporate events that occur prior to the maturity date or if the Company issues a notice of redemption, the Company will increase the conversion rate for a holder who elects to convert its 2027 Notes in connection with such a corporate event during the related redemption period in certain circumstances. The 2027 Notes are senior unsecured obligations of the Company, ranking senior in right of payment to any of the Company’s indebtedness that is expressly subordinated in right of payment to the 2027 Notes, and are effectively subordinated to the Company’s existing and future secured indebtedness, to the extent of the value of the collateral securing that indebtedness. Holders may convert their notes at their option only in the following circumstances: (1) during any calendar quarter (and only during such calendar quarter) commencing after the calendar quarter ending on September 30, 2020, if the last reported sale price per share of the Company’s common stock exceeds 130 % of the conversion price for each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five consecutive business days immediately after any 10 consecutive trading day period (such 10 consecutive trading day period, the “measurement period”) in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98 % of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company’s common stock; (4) if the Company calls such notes for redemption; and (5) at any time from, and including, March 1, 2027 until the close of business on the scheduled trading day immediately before the maturity date. The Company did not have the right to redeem the 2027 Notes prior to June 6, 2024. As of December 31, 2025, the Company has not redeemed the 2027 Notes. On or after June 6, 2024 and on or before the 50 th scheduled trading day immediately before the maturity date, the Company may redeem the 2027 Notes, in whole or in part, if the last reported sale price of the Company’s common stock has been at least 130 % of the conversion price then in effect on (1) each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (2) the trading day immediately before the date the Company sends such notice. In the case of any optional redemption, the Company will redeem the 2027 Notes at a redemption price equal to 100 % of the principal amount of such Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. If the Company undergoes a fundamental change prior to the maturity date of the 2027 Notes, holders of the 2027 Notes may require the Company to repurchase for cash all or part of their 2027 Notes at a repurchase price equal to 100 % of the principal amount of the 2027 Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. The indenture governing the 2027 Notes provides for customary terms and covenants, including that upon certain events of default, either the trustee or the holders of not less than 25 % in aggregate principal amount of the 2027 Notes then outstanding may declare the unpaid principal amount of the 2027 Notes and accrued and unpaid interest, if any, thereon immediately due and payable. As of December 31, 2025, the Company was in compliance with these covenants. In the case of F-16 Table of Contents certain events of bankruptcy, insolvency or reorganization, the principal amount of the 2027 Notes together with accrued and unpaid interest, if any, thereon will automatically become and be immediately due and payable. As of December 31, 2025 and 2024, there were no events or market conditions that would allow holders to convert the 2027 Notes. When the 2027 Notes become convertible within 12 months of the balance sheet date, the carrying value of the 2027 Notes will be reclassified to short-term. The Company accounts for the 2027 Notes as a single liability measured at amortized cost. As the equity component is no longer required to be split into a separate component, the Company recorded an adjustment to reflect this update. The Company recorded $ 0.4 million of the debt issuance costs related to the 2027 Notes as a reduction to the liability and amortizes these costs to interest expense over the term of the 2027 Notes. The net carrying amount of the 2027 Notes was as follows (in thousands): December 31, 2025 2024 Principal amount $ 200,000 $ 200,000 Unamortized debt discount ( 1,398 ) ( 2,321 ) Unamortized debt issuance cost ( 94 ) ( 156 ) Net carrying amount $ 198,508 $ 197,523 The following table sets forth the interest expense recognized related to the 2027 Notes (in thousands): Year Ended December 31, 2025 2024 2023 Contractual interest expense $ 10,000 $ 10,000 $ 10,000 Amortization of debt discount 923 873 826 Amortization of debt issuance cost 62 59 56 Total interest expense related to the 2027 Notes $ 10,985 $ 10,932 $ 10,882 Note 6— Licenses, Asset Acquisitions and Contingent Consideration The following purchased assets were accounted for as asset acquisitions as substantially all of the fair value of the assets acquired were concentrated in a group of similar assets and/or the acquired assets were not capable of producing outputs due to the lack of employees and early stage of development. Because the assets had not yet received regulatory approval, the fair value attributable to these assets was recorded as in process research and development (“IPR&D”) expenses in the Company’s consolidated statements of operations and comprehensive loss for the years ended December 31, 2025, 2024, and 2023. The Company accounts for contingent consideration payable upon achievement of certain regulatory, development or sales milestones in such asset acquisitions when the underlying contingency is met. License from Pulmokine, Inc. (Seralutinib) On October 2, 2017, the Company entered into a license agreement with Pulmokine, Inc. under which it was granted an exclusive worldwide license and sublicense to certain intellectual property rights owned or controlled by Pulmokine to develop and commercialize seralutinib and certain backup compounds for the treatment, prevention and diagnosis of any and all disease or conditions. On November 26, 2024, Pulmokine became a wholly-owned subsidiary of XOMA Royalty Corporation. The Company also has the right to sublicense its rights under the license agreement, subject to certain conditions. The assets acquired are in the early stages of the FDA approval process, and the Company intends to further develop the assets acquired through potential FDA approval as evidenced by the milestone arrangement in the contract. The development activities cannot be performed without significant cost and effort by the Company. The agreement will remain in effect from the effective date, unless terminated earlier, until, on a licensed product-by-licensed product and country-by-country basis, the later of ten F-17 Table of Contents years from the date of first commercial sale or when there is no longer a valid patent claim covering such licensed product or specified regulatory exclusivity for the licensed product in such country. The Company is obligated to make future development and regulatory milestone payments of up to $ 48.0 million, which includes a payment of $ 5.0 million due upon initiation of a Phase 3 clinical trial in a second indication, commercial milestone payments of up to $ 45.0 million, and sales milestone payments of up to $ 190.0 million. The Company is also obligated to pay tiered royalties on sales for each licensed product, at percentages ranging from the mid-single digits to the high single-digits. In addition, if the Company chooses to sublicense or assign to any third parties its rights under the agreement with respect to a licensed product, or the Company’s seralutinib operating subsidiary undergoes a change of control, the Company must pay to Pulmokine a specified percentage of all revenue to be received in connection with such transaction. The Company made an upfront payment of $ 5.5 million in October 2017. The Company made a milestone payment of $ 5.0 million in connection with the initiation of the first Phase 2 clinical trial of seralutinib in January 2021 and made a milestone payment of $ 10.0 million, which was accrued in 2023, in connection with the initiation of the Phase 3 clinical trial of seralutinib in January 2024. The Company recognized these milestone payments as research and development expense on its consolidated statements of operations and comprehensive loss. As of December 31, 2025, no other milestones had been accrued as the underlying contingencies had not yet been met. The Company recorded the following IPR&D expense on the consolidated statements of operations and comprehensive loss (in thousands): Year Ended December 31, 2025 2024 2023 Seralutinib $ — $ — $ 10,000 Note 7— Income Taxes The amount of net loss before taxes for the years ended December 31, 2025, 2024, and 2023 is as follows: December 31, 2025 2024 2023 (in thousands) U.S. loss before taxes $ 138,048 $ 32,178 $ 134,073 Foreign loss before taxes 32,410 23,457 45,736 Pre-tax Loss $ 170,458 $ 55,635 $ 179,809 A reconciliation of income tax expense (benefit) for the years ended December 31, 2025, 2024 and 2023 is as follows: December 31, 2025 2024 2023 (in thousands) Current: Federal $ ( 94 ) $ 886 $ — State 6 7 8 Total income tax expense (benefit) $ ( 88 ) $ 893 $ 8 Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities at December 31, 2025, 2024 and 2023 are shown below. The Company has established a valuation allowance against net deferred tax assets due to the uncertainty that such assets will be realized. The Company periodically evaluates the recoverability of the deferred assets. At such time as it is determined that it is more likely than not that the deferred tax asset will be realized, the valuation allowance will be reduced. The change in the valuation allowance for the year ended December 31, 2025 was an increase of $ 45.0 million. F-18 Table of Contents For the Year Ended December 31, 2025 2024 2023 (in thousands) Deferred tax assets: Net operating losses $ 132,088 $ 97,940 $ 122,987 Deferred loss 9,323 10,575 — Capital loss 20,163 20,348 — Tax credits 60,579 44,803 45,445 Amortization 2,409 2,646 6,919 Stock-based compensation 11,239 10,984 9,886 Lease liability 937 1,135 726 Accrued compensation 1,979 547 1,887 Section 174 capitalization 30,242 35,715 34,268 Other 5,621 5,076 43 Total gross deferred tax assets 274,580 229,769 222,161 Deferred tax liabilities: Other ( 13 ) ( 3 ) — Right of use asset ( 881 ) ( 1,083 ) ( 660 ) Property, plant and equipment — — ( 108 ) Total gross deferred tax liabilities ( 894 ) ( 1,086 ) ( 768 ) Valuation allowance ( 273,686 ) ( 228,683 ) ( 221,393 ) Net deferred tax asset $ — $ — $ — As of December 31, 2025, the Company had federal and state NOL carryforwards of approximately $ 540.6 million and $ 10.2 million, respectively. The majority of the federal NOL carryforwards can be carried forward indefinitely and be available to offset up to 80 % of future taxable income each year. The state NOL carryforwards begin to expire in 2036. As of December 31, 2025, the Company also has Irish NOL carryforwards of approximately $ 143.3 million, which can be carried forward indefinitely. As of December 31, 2025, the Company also had orphan drug credit and federal research tax credit carryforwards of approximately $ 65.8 million and California research tax credits of $ 12.0 million. The federal research tax credit carryforwards begin to expire in 2038, and the California research tax credit carryforward does not expire and can be carried forward indefinitely until utilized. Upon adoption of ASU 2023-09, the differences between income taxes expected at the U.S. federal statutory income tax rate of 21% and the reported income tax (benefit) expense are summarized as follows: F-19 Table of Contents Year Ended December 31, 2025 (in thousands) Federal statutory income tax rate $ ( 35,795 ) 21.0 % State income taxes, net of federal benefit (1) 5 — % Foreign Tax Effects Ireland Statutory tax rate difference between Ireland and United States 4,245 ( 2.5 %) Change in valuation allowance 1,916 ( 1.1 %) Other Adjustments 644 ( 0.4 %) Tax Credits Research and development credit, net ( 1,386 ) 0.8 % Orphan Drug Credit, net ( 14,230 ) 8.3 % Change in valuation allowance 41,203 ( 24.2 %) Nontaxable or nondeductible items Non-Deductible Interest 2,307 ( 1.4 %) Other 1,277 ( 0.7 %) Other Adjustments ( 274 ) 0.2 % Effective Tax Rate $ ( 88 ) — % (1) Income taxes in California made up the majority (greater than 50 percent) of the tax effect in this category. The reconciliation of the federal statutory income tax rate to the Company's effective income tax rate in accordance with the guidance prior to the adoption of ASU 2023-09 was as follows: Year Ended December 31, Reconciliation to U.S. Statutory Rate 2024 2023 Federal statutory income tax rate 21.00 % 21.00 % Change in valuation allowance ( 12.38 %) ( 8.73 %) Research and experimentation credits 3.03 % 5.69 % Foreign rate differential ( 3.75 %) ( 2.13 %) GILTI ( 4.72 %) — % Stock-based compensation ( 4.61 %) ( 1.44 %) Nondeductible interest ( 4.13 %) ( 1.27 %) Domestic/Foreign Restructuring Impact 2.52 % ( 12.49 %) Other 1.44 % ( 0.62 %) Effective Tax Rate ( 1.60 %) 0.01 % The NOL carryforward may be subject to an annual limitation under Section 382 and 383 of the Internal Revenue Code of 1986, and similar state provisions if the Company experienced one or more ownership changes which would limit the amount of NOL and tax credit carryforwards that can be utilized to offset future taxable income and tax respectively. In general, an ownership change as defined by Sections 382 and 383, results from the transactions increasing ownership of certain stockholders or public groups in the stock of the corporation of more than 50 percentage points over a three-year period. The Company had an ownership change with the IPO in February of 2019 which resulted in no forfeiture of NOLs or credits. The Company had an additional ownership change in July of 2023, which resulted in a significant limitation on the Company's utilization of its NOLs and is expected to result in forfeiture of some federal net operating losses and all of the pre-change federal credits. Due to the existence of the valuation allowance, limitations created by future ownership changes, if any, will not impact the Company’s effective tax rate. The Company files income tax returns in the United States, California, Florida and Ireland. Due to the Company’s losses incurred, the Company is subject to the income tax examination by authorities since inception. The Company’s policy is to recognize interest expense and penalties related to income tax matters as tax expense. For the years ended December 31, 2025, 2024 and 2023 and as of December 31, 2025 and 2024, there were no accruals for interest related to unrecognized tax benefits or tax penalties. F-20 Table of Contents A reconciliation of the beginning and ending amount of unrecognized tax benefits for 2025, 2024, and 2023, excluding interest and penalties, is as follows: December 31, 2025 2024 2023 (in thousands) Balance at beginning of the year $ 13,919 $ 13,654 $ 10,572 Decrease related to prior year positions ( 1,359 ) ( 2,028 ) — Increase related to current year positions 2,902 2,293 3,082 Balance at the end of the year $ 15,462 $ 13,919 $ 13,654 Included in the balance of unrecognized tax benefits at December 31, 2025 is $ 15.5 million that, if recognized, would not impact the Company’s income tax benefit or effective tax rate as long as the Company's deferred tax asset remains subject to a full valuation allowance. The company did not make any material income tax payments for federal, state or foreign purposes. Note 8— Stockholders’ Equity (Deficit) Common Stock Each share of common stock is entitled to one vote. Common stock owners are entitled to dividends when funds are legally available and declared by the Company's board of directors. Private Placement Financing On July 24, 2023, the Company completed a private placement of 129,869,440 shares of the Company’s common stock and accompanying warrants to purchase up to 32,467,360 shares of the Company's common stock at a combined purchase price of $ 1.63125 per share and accompanying warrant, or with respect to any purchaser that was an officer, director, employee or consultant of the Company $ 1.85125 , per share and accompanying warrant. Each warrant has an exercise price per share of $ 2.04 , was immediately exercisable on the date of issuance and will expire five years from the closing of the private placement. The aggregate gross proceeds for the private placement were $ 212.1 million, before deducting offering expenses, which equaled $ 10.8 million. On August 18, 2023, the Company filed a registration statement on Form S-3 registering the shares of common stock and shares of common stock issuable upon the exercise of warrants issued in the private placement, which registration statement was declared effective on August 28, 2023. Shares of Common Stock Subject to Repurchase On December 3, 2015, the Company issued 9,160,888 shares of common stock as founder shares for services rendered to the Company, valued at $ 0.0001 par value per share, for a total of approximately $ 4,100 (the “founder shares”). On January 4, 2018, incremental vesting conditions were placed on the previously issued founder shares. Fifty percent of the previously issued founder shares vested on January 4, 2018, and the remaining founder shares are subject to vesting restrictions over a period of five years . These shares are subject to repurchase by the Company upon a founder's termination of employment or service to the Company. Pursuant to the employment agreements with the Company’s founders executed January 4, 2018, the Company provided for certain potential additional issuances of common stock (the “anti-dilution shares”) to each of the founders to ensure the total number of shares of common stock held by them and their affiliates (inclusive of any shares subject to equity awards granted by the Company) would represent 15 % of the Company’s fully-diluted capitalization until such time as the Company raised $ 300.0 million in equity capital, including the capital raised in the Series A financing. In furtherance of this obligation, on May 21, 2018, the Company issued 251,547 shares of common stock to the founders for services rendered to the Company, valued at $ 2.61 per share with an additional 251,547 shares of restricted stock subject to the same vesting restrictions and vesting period as the founder shares. In addition, on September 6, 2018, the Company issued 1,795,023 shares of common stock to the founders for services rendered to the Company, valued at $ 9.63 per share, with an additional 1,795,023 shares of restricted stock subject to the same vesting restrictions and vesting period as the founder shares. Any shares subject to repurchase by the Company are not deemed, for accounting purposes, to be outstanding until those shares vest. As such, the Company recognizes the measurement date fair value of the restricted stock over the F-21 Table of Contents vesting period as compensation expense. As of December 31, 2025, there were no shares of common stock subject to repurchase by the Company. The unvested stock liability related to these awards is immaterial to all periods presented. Chiesi Equity Option On May 3, 2024, pursuant to the Chiesi Collaboration Agreement (as defined in Note 12 below) the Company granted to Chiesi (as defined in Note 12 below) an option to purchase directly from the Company, on one or more occasions, up to an aggregate number of shares of the Company’s common stock (the "Equity Option") such that immediately following such issuance, Chiesi’s beneficial ownership of the Company’s common stock shall not exceed 9.9 % of the total number of issued and outstanding shares of the Company’s common stock. The Equity Option shall be exercisable by Chiesi, in whole or in part, at any time prior to the earliest to occur of the date on which (a) the last patient is last dosed in either (i) the PROSERA Phase 3 study for PAH or (ii) a Phase 3 clinical trial for the PH-ILD Indication, (b) any third party commences a tender offer or exchange offer for more than 50 % of the outstanding shares of the Company’s common stock, and (c) the Company publicly announces its intent to consummate a GB002, Inc. change of control. The purchase price of each share the Company’s common stock subject to the Equity Option shall be equal to 107.5 % of the daily volume-weighted average per share price of the Company’s common stock on The Nasdaq Stock Market over the 30 -trading day period ending on and including the last trading day prior to the date on which Chiesi delivers an exercise notice to the Company; provided that such purchase price shall be no less than $ 1.63 per share. The shares of the Company’s common stock to be issued will be issued in a private placement in reliance on Section 4(a)(2) of the Securities Act of 1933, as amended, for transactions by an issuer not involving any public offering, pursuant to the terms of a stock issuance agreement to be entered into between the Company and Chiesi in connection with each such exercise of the Equity Option. The Company evaluated the Equity Option granted to Chiesi as consideration payable to a customer and determined it qualified under ASC 718. Due to the market condition included in the Equity Option, the Company used the Geometric Brownian Motion/Monte Carlo model to determine fair market value. The value of the Equity Option is $ 0.5 million, which is included in additional paid-in capital on the Company's consolidated balance sheets. In November 2025, the Equity Option expired and is no longer exercisable. Note 9— Equity Incentive Plans 2023 Equity Inducement Incentive Plan In November 2023, the Company approved the 2023 Employment Inducement Incentive Plan (the "2023 Inducement Plan"). The terms of the 2023 Inducement Plan are substantially similar to the terms of the Company’s 2019 Incentive Award Plan (as described below) with the exception that incentive stock options may not be issued under the 2023 Inducement Plan and awards under the 2023 Inducement Plan may only be issued to eligible recipients under the applicable Nasdaq rules. The 2023 Inducement Plan was adopted without stockholder approval pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. In accordance with Rule 5635(c)(4) of the Nasdaq Listing Rules, awards under the 2023 Inducement Plan may only be made to an employee who has not previously been an employee or member of the board of directors of the Company or any parent or subsidiary, or following a bona fide period of non-employment by the Company or a parent or subsidiary, if he or she is granted such award in connection with his or her commencement of employment with the Company or a subsidiary and such grant is an inducement material to his or her entering into employment with the Company or such subsidiary. The Company has initially reserved 6,762,279 shares of the Company’s common stock for issuance pursuant to awards granted under the 2023 Inducement Plan. As of December 31, 2025, an aggregate of 1,856,658 shares of common stock were available for issuance under the 2023 Inducement Plan, and 4,811,455 shares of common stock were subject to outstanding awards under the 2023 Inducement Plan. 2019 Equity Incentive Plan In January 2019, the Company’s board of directors and stockholders approved and adopted the 2019 Incentive Award Plan (the “2019 Plan”). The 2019 Plan became effective on February 6, 2019, the day prior to the effectiveness of the registration statement filed in connection with the IPO. Under the 2019 Plan, the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units, and other stock or cash-based awards to individuals who are then employees, officers, directors or consultants of the Company, and employees and consultants of the Company’s subsidiaries. A total of 5,750,000 shares of common stock were approved to be initially reserved for issuance under the 2019 Plan. The number of shares that remained available for issuance under the 2017 Plan (as defined below) as of the effective date of the 2019 Plan were, and shares subject to outstanding awards under the 2017 Plan as of the effective date of the 2019 Plan that are subsequently canceled, forfeited or repurchased by the Company will be added to the shares reserved under the 2019 Plan. The Company’s board of directors and stockholders approved an amendment and restatement to the 2019 Plan in 2025 to, among other things, increase the aggregate number of shares of common stock authorized for issuance under the 2019 Plan by 11,350,000 shares of common stock. In addition, the number of shares of common stock available for issuance under the 2019 Plan will be automatically increased on the first day of each calendar year during the ten-year term of the 2019 Plan, beginning F-22 Table of Contents with January 1, 2026 and ending with January 1, 2035, by an amount equal to 5 % of the outstanding number of shares of the Company’s common stock on December 31 of the preceding calendar year or such lesser amount as determined by the Company’s board of directors. As of December 31, 2025, an aggregate of 8,445,734 shares of common stock were available for issuance under the 2019 Plan and 44,796,989 shares of common stock were subject to outstanding awards under the 2019 Plan. 2019 Employee Stock Purchase Plan In January 2019, the Company’s board of directors and stockholders approved and adopted the 2019 Employee Stock Purchase Plan (the "ESPP"). The ESPP became effective as of February 6, 2019, the day prior to the effectiveness of the registration statement filed in connection with the IPO. The ESPP permits participants to purchase common stock through payroll deductions of up to 20 % of their eligible compensation. A total of 700,000 shares of common stock were approved to be initially reserved for issuance under the ESPP. In addition, the number of shares of common stock available for issuance under the ESPP will be automatically increased on the first day of each calendar year during the first ten years of the term of the ESPP, beginning with January 1, 2020 and ending with January 1, 2029, by an amount equal to 1 % of the outstanding number of shares of the Company’s common stock on December 31 of the preceding calendar year or such lesser amount as determined by the Company’s board of directors. During the years ended December 31, 2025 and 2024, 1,089,883 shares and 767,125 shares were issued pursuant to the ESPP, respectively. As of December 31, 2025, an aggregate of 5,721,970 shares of common stock were available for issuance under the ESPP. 2017 Equity Incentive Plan The Company’s 2017 Equity Incentive Plan (the “2017 Plan”) permitted the granting of incentive stock options, non-statutory stock options, restricted stock, restricted stock units and other stock-based awards. Subsequent to the adoption of the 2019 Plan, no additional equity awards can be made under the 2017 Plan. As of December 31, 2025, 1,955,471 shares of common stock were subject to outstanding options under the 2017 Plan, and no shares of restricted stock awards granted under the 2017 Plan were unvested. Stock Options The fair value of each employee and non-employee time-vested stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company uses its own volatility to the extent it has sufficient trading history, and for awards in which sufficient trading history is not available, a peer group is used to calculate the expected volatility. Due to the lack of historical exercise history, the expected term of the Company’s stock options for employees has been determined utilizing the “simplified” method for awards. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is zero based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. On May 5, 2023, the Company granted to its Chairman and Chief Executive Officer 750,000 options with an exercise price of $ 1.36 per share. This grant contains both service and market based vesting conditions. The awards vest on the later of the date of achievement and the one-year anniversary of the grant date. The market condition becomes satisfied in 50 %, 25 % and 25 % tranches upon achieving the average per-share closing price of the Company's common stock over any 30 consecutive calendar days following the grant date equal to or exceeding $ 5.00 , $ 7.50 and $ 10.00 , respectively. In the event a stock price tranche has not vested prior to the fourth anniversary of the grant date, any portion of the option attributable to such tranche will be forfeited. Due to the market condition included in this grant, the Company used the Geometric Brownian Motion/Monte Carlo model to value this award. The total stock-based compensation expense related to this award is $ 0.4 million, which is included in general and administrative expense on the consolidated statements of operations and comprehensive loss. The Company expects to recognize this expense over a weighted average period of approximately 2.2 years. Effective May 5, 2023, and in accordance with the terms of the 2019 Plan, the Company's board of directors approved a stock option repricing (the “Option Repricing”) whereby the exercise price of each Eligible Option (as defined below) was immediately reduced to $ 1.36 per share, the closing stock price on May 5, 2023. For purposes of the Option Repricing, “Eligible Options” are 6,817,057 outstanding stock options as of May 5, 2023 (vested or unvested) granted under the 2019 Plan prior to November 30, 2022 and held by those eligible employees of the Company identified by the Company's board of directors, including the Company’s executive officers, except for the Company’s Chairman and Chief Executive Officer. The participation of the executive officers of the Company in the Option Repricing was subject to their agreement to cancel a portion of their Eligible Options effective immediately (the “Cancelled Options”). Each executive was F-23 Table of Contents required to agree to cancel one-third of his or her Eligible Options, on a grant-by-grant basis. The Cancelled Options were deducted proportionately from the vested and unvested portions of each Repriced Option grant. To the extent an Eligible Option is exercised prior to the Premium End Date (as defined below), or the eligible employee’s employment terminates prior to the Premium End Date, the eligible employee will be required to pay the original exercise price per share of the Eligible Options in connection with any exercise of the Eligible Option. The “Premium End Date” means the earliest of (i) May 5, 2024, (ii) the date of a change in control, (iii) the eligible employee’s death or disability, or (iv) if an eligible employee is an executive subject to the cancellation of a portion of Eligible Options and is terminated under circumstances giving rise to severance under his or her employment agreement, the date of such termination. Except for the reduction in the exercise prices of the Eligible Options as described above, the Eligible Options will retain their existing terms and conditions as set forth in the 2019 Plan and the applicable award agreements. The repricing resulted in $ 3.4 million of incremental cost, which was calculated using the Black-Scholes option-pricing model, of which $ 2.0 million of the incremental cost was recognized immediately, and $ 1.4 million of the incremental cost will be recognized on the straight-line basis over the remaining vesting period of the repriced options. The incremental cost is included in general and administrative expense and research and development expense on the consolidated statements of operations and comprehensive loss. The following assumptions were used to estimate the fair value of stock option awards granted to employees under the Company’s equity incentive plans and the shares purchasable under the ESPP during the periods presented: Year Ended December 31, 2025 2024 2023 Employee Stock Options Expected term (in years) 4.6 - 6.1 4.6 - 6.1 1.0 - 7.0 Risk-free interest rate 3.70 % - 4.47 % 3.59 % - 4.50 % 3.36 % - 4.73 % Volatility 98.10 % - 105.73 % 100.72 % - 104.51 % 70.01 % - 170.69 % Dividend yield — — — Employee Stock Purchase Plan Expected term (in years) 0.5 - 2.0 0.5 - 2.0 0.5 - 2.0 Risk-free interest rate 3.66 % - 4.31 % 3.88 % - 5.27 % 3.88 % - 5.27 % Volatility 75.01 % - 92.92 % 83.96 % - 151.54 % 83.96 % - 151.54 % Dividend yield — — — F-24 Table of Contents The following table summarizes stock option activity for the years ended December 31, 2025, 2024 and 2023: Shares Subject to Options Outstanding Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value Shares Weighted- Average Exercise Price (in thousands) Outstanding as of December 31, 2022 17,487,165 $ 9.24 8.1 $ 47 Options granted 17,159,617 $ 1.16 Options exercised — $ — Options forfeited/cancelled ( 11,020,667 ) $ 11.07 Outstanding as of December 31, 2023 23,626,115 $ 2.52 7.9 $ 369 Options granted 13,006,228 $ 0.96 Options exercised — $ — Options forfeited/cancelled ( 2,216,006 ) $ 2.25 Outstanding as of December 31, 2024 34,416,337 $ 1.95 7.5 $ 598 Options granted 15,988,420 $ 1.23 Options exercised ( 1,691,213 ) $ 1.14 Options forfeited/cancelled ( 1,276,591 ) $ 1.79 Outstanding as of December 31, 2025 47,436,953 $ 1.74 7.4 $ 84,257 Options vested and expected to vest as of December 31, 2025 47,436,953 $ 1.74 7.4 $ 84,257 Options exercisable as of December 31, 2025 21,205,852 $ 2.48 6.2 $ 32,775 The weighted-average grant date fair value per share for the stock options granted during the year ended December 31, 2025, 2024 and 2023 was $ 0.98 , $ 0.78 and $ 3.88 , respectively. The aggregate fair value of stock options that vested during the years ended December 31, 2025, 2024 and 2023 was $ 9.3 million, $ 15.7 million and $ 22.7 million, respectively. The aggregate intrinsic value in the above table is calculated as the difference between fair value of the Company’s common stock price and the exercise price of the stock options. There were no options exercised during the years ended December 31, 2024 and 2023. The aggregate intrinsic value of stock options exercised during the year ended December 31, 2025 was $ 2.7 million. Warrants On July 24, 2023, the Company completed a private placement of 129,869,440 shares of the Company’s common stock and accompanying warrants to purchase up to 32,467,360 shares of the Company's common stock at a combined purchase price of $ 1.63125 per share and accompanying warrant, or with respect to any purchaser that was an officer, director, employee or consultant of the Company, $ 1.85125 per share and accompanying warrant. Each warrant has an exercise price per share of $ 2.04 , was immediately exercisable on the date of issuance and will expire five years from the closing of the private placement. Given that the warrants are indexed to the Company's shares of common stock (and otherwise meet the requirements to be classified in equity), the Company recorded the consideration received from the issuance of the warrants as additional paid-in capital on the Company's consolidated balance sheets. During the year ended December 31, 2025, 1,791,823 warrants were exercised. As of December 31, 2025, there were 30,675,537 warrants outstanding. F-25 Table of Contents Restricted Stock There was no restricted stock outstanding during the year ended December 31, 2025. The summary of the Company’s restricted stock activity during the years ended December 31, 2024 and 2023 is as follows: Number of Restricted Stock Units Outstanding Weighted- Average Grant Date Fair Value Nonvested at December 31, 2022 1,350,035 $ 10.83 Granted — — Vested ( 779,900 ) 10.67 Forfeited / cancelled ( 142,437 ) 11.39 Nonvested at December 31, 2023 427,698 $ 10.92 Granted — — Vested ( 427,698 ) 10.92 Forfeited / cancelled — — Nonvested at December 31, 2024 — $ — As of December 31, 2025, there was no unrecognized stock-based compensation expense related to the unvested restricted stock awards. Performance Stock Units The fair value of the performance stock units ("PSUs") is determined based on the closing market price of the Company's common stock on the grant date. Compensation expense for PSUs is recognized if and when the Company concludes that it is probable that the performance conditions will be achieved. The Company reassesses the probability of vesting at each reporting period for awards with performance conditions and adjusts compensation expense based on its probability assessment. All PSUs vest in full upon the earlier of (i) the approval of an NDA for seralutinib or (ii) a Change in Control (as defined in the 2019 Plan), in either case on or prior to the fourth anniversary of the grant date, and subject to the participant not experiencing a termination of service prior to the applicable vesting date. In the event the PSUs have not vested on or prior to the fourth anniversary of the grant date due to the failure of either of the above events to occur, the PSUs will be forfeited on such date. As of December 31, 2025, the Company determined that the achievement of the performance condition of the PSUs is not probable, and therefore no compensation expense was recorded during the year ended December 31, 2025. There were no performance stock units outstanding during the years ended December 31, 2024 and 2023. The summary of the Company’s performance stock units activity during the year ended December 31, 2025 is as follows: Number of Performance Stock Units Outstanding Weighted- Average Grant Date Fair Value Nonvested at December 31, 2024 — $ — Granted 4,191,337 1.70 Vested — — Forfeited / cancelled ( 64,375 ) 1.25 Nonvested at December 31, 2025 4,126,962 $ 1.71 Stock-Based Compensation Expense Stock-based compensation expense has been reported in the Company’s consolidated statements of operations and comprehensive loss as follows (in thousands): Year Ended December 31, 2025 2024 2023 Research and development $ 5,221 $ 10,172 $ 15,871 General and administrative 5,334 10,447 12,647 Total stock-based compensation expense $ 10,555 $ 20,619 $ 28,518 F-26 Table of Contents At December 31, 2025, the total unrecognized stock-based compensation expense related to the unvested stock option awards granted was $ 19.4 million, which the Company expects to recognize over a weighted-average period of approximately 2.5 years. As of December 31, 2025, the total unrecognized stock-based compensation expense related to the unvested performance stock units granted was $ 7.1 million, which the Company expects to recognize over a weighted-average period of approximately 1.1 years. As of December 31, 2025, the total unrecognized compensation expense related to the ESPP was $ 0.6 million, which the Company expects to recognize over a weighted-average period of approximately 0.8 years. Note 10— Property and Equipment, Net The Company’s property and equipment, net consisted of the following (in thousands): Estimated Useful Life (in years) December 31, 2025 December 31, 2024 Lab equipment 2 - 5 193 193 Leasehold improvements 6 - 7 78 — Total property and equipment 271 193 Less: accumulated depreciation ( 207 ) ( 183 ) Property and equipment, net $ 64 $ 10 Depreciation expense for the years ended December 31, 2024 and 2023 was approximately $ 0.8 million and $ 1.6 million, respectively, and was recorded in general and administrative expense and research and development expense, respectively, on the consolidated statements of operations and comprehensive loss. The depreciation expense for the year ended December 31, 2025 was immaterial . Note 11— Commitments and Contingencies Leases The Company previously leased certain office and laboratory space under a non-cancelable operating lease which expired in January 2025. On July 9, 2024, the Company entered into a lease agreement for office space located at 3115 Merryfield Row, Suite 120, San Diego, CA 92121, consisting of approximately 18,421 square feet. The term of the lease is 63 months commencing on August 1, 2024. The base rent is $ 109,605 per month effective October 1, 2024, and it is subject to a 3 % annual increase every October. The lease expires on October 31, 2029 with an option for a one -year extension and an option to terminate on December 1, 2027 with the payment of a termination fee equal to four months of the then-current base rent upon the termination date. As of December 31, 2025, the Company was not reasonably certain that it would exercise the extension options, and therefore did not include these options in the determination of the total operating lease term for accounting purposes. Monthly rent expense is recognized on a straight-line basis over the term of the leases. The operating leases are included in the consolidated balance sheets at the present value of the lease payments at an incremental borrowing rate of 7 % for each of the initial leased space and expansion space expiring in January 2025 and 12.4 % for the office lease commenced on August 1, 2024 using the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment as the leases do not provide an implicit rate. As of December 31, 2025, the weighted average remaining lease term was 3.8 years, and weighted-average discount rate was 12.4 %. Lease costs were comprised of the following (in thousands): Year Ended December 31, 2025 2024 2023 Operating lease cost $ 1,567 $ 3,706 $ 3,114 Short-term lease cost 17 48 52 Total lease cost $ 1,584 $ 3,754 $ 3,166 F-27 Table of Contents Cash paid for amounts included in the measurement of operating lease liabilities as of December 31, 2025, 2024 and 2023 was $ 1.8 million, $ 3.8 million and $ 3.3 million, respectively. Gross future minimum annual rental commitments as of December 31, 2025, were as follows (in thousands): Undiscounted Rent Payments Year ending December 31, 2026 $ 1,417 2027 1,406 2028 1,448 2029 1,237 Total undiscounted rent payments $ 5,508 Present value discount ( 1,110 ) Present value of lease payments $ 4,398 Current portion of operating lease liabilities (included as a component of accrued expenses and other current liabilities) 938 Operating lease liabilities - long-term 3,460 Total operating lease liability $ 4,398 Note 12 - Significant Agreements and Contracts On May 3, 2024, the Company, GB002, Inc., a Delaware corporation and wholly-owned subsidiary of the Company and Gossamer Bio 002 Ltd., a corporation organized and existing under the laws of Ireland and indirect wholly-owned subsidiary of the Company, entered into a global collaboration and license agreement (the “Chiesi Collaboration Agreement”) with Chiesi Farmaceutici S.p.A and Chiesi USA, Inc. (collectively, “Chiesi”). The Company concluded that there were four distinct performance obligations under the Chiesi Collaboration Agreement: the U.S. Territory license (as defined below), the ROW Territory license (as defined below), the research and development services of PAH clinical development and the research and development services of PH-ILD clinical development. Revenue associated with the licenses was recognized upon delivery in May 2024. In addition, the Company granted to Chiesi an option to purchase the Equity Option, as described in Note 8, "Stockholders Equity." The collaboration is focused on the development and commercialization of seralutinib and licensed products including seralutinib and related licensed compounds (“Licensed Products”) in the U.S. (“U.S. Territory”) and the rest of the world (“ROW Territory”), for therapeutic, prophylactic and diagnostic uses in humans and animals, for the treatment of PAH and PH-ILD and other indications, as may be permitted under the Chiesi Collaboration Agreement. Pursuant to the Chiesi Collaboration Agreement, the Company granted two exclusive, sublicensable (with the Company’s consent required in the U.S. Territory for third party sublicenses) licenses to Chiesi under intellectual property rights controlled by the Company relating to seralutinib and Licensed Products, for the worldwide development, manufacture and commercialization of seralutinib and Licensed Products. The licenses granted to Chiesi are subject to retained rights of the Company for the worldwide development and manufacture of seralutinib and Licensed Products, commercialization of Licensed Products in the U.S. Territory, and performance of its obligations and exercise of its rights that may be set forth in the global development plan and U.S. commercialization plan, in each case in accordance with the Chiesi Collaboration Agreement. The parties agreed to use commercially reasonable efforts to conduct development and commercialization activities in relation to seralutinib and Licensed Products, under the global development plan and U.S. commercialization plan in accordance with the timelines therein. The Company will continue to lead global development of seralutinib in PAH and PH-ILD, and the parties will equally share the costs for the activities included in the global development plan for all Licensed Products, with the exception of the PROSERA Phase 3 study, which the Company will be solely responsible for conducting at the Company’s own cost and expense. With respect to each country in the ROW Territory, such obligation to equally share such development costs shall end when regulatory approval is received for a Licensed Product in such country. With respect to U.S. Territory, the development costs incurred following regulatory approval shall continue to be shared equally. The Company will lead potential commercialization for PAH and PH-ILD in the U.S. Territory, with both parties contributing 50 percent of commercial efforts, including performing 50 percent of the commercialization activities. Chiesi will lead potential commercialization in the U.S. Territory in any additional indications, and Chiesi will have the exclusive right to commercialize F-28 Table of Contents Licensed Products in the ROW Territory. Chiesi further agreed to use commercially reasonable efforts to commercialize Licensed Products in certain specified countries in the ROW Territory following receipt of regulatory approvals. Generally, the Company will have the right to lead in manufacturing commercial supply of seralutinib and Licensed Products for the U.S. Territory for PAH and PH-ILD, and, subject to any existing obligations of the Company to third party manufacturers, Chiesi will have the right to lead in manufacturing commercial supply of seralutinib and Licensed Products in the ROW Territory, in each case in accordance with the Chiesi Collaboration Agreement. Pursuant to the Chiesi Collaboration Agreement, neither party nor its affiliates is permitted to develop or commercialize any compound or product throughout the term whose primary mechanism of action is inhibition of a tyrosine kinase for the treatment of PAH or PH-ILD in the U.S. Territory or ROW Territory, subject to certain restrictions for the European Union and United Kingdom. In consideration and as reimbursement for the Company’s development costs, Chiesi agreed to pay the Company an up-front, nonrefundable payment of $ 160 million. Additionally, the Company will be eligible to receive up to $ 146 million in regulatory milestones and $ 180 million in sales milestones. In the U.S. Territory, the parties agreed to share commercial profits and losses equally. In the ROW Territory, Chiesi will pay the Company an escalating mid-to-high teens percentage royalty on net sales of Licensed Product for PAH and additional indications on a Licensed Product-by-Licensed Product and country-by-country basis with such payment obligations beginning on the first commercial sale of Licensed Product in such country and expiring on a country-by-country basis on the latest of (a) the expiration of a valid claim to a the Company patent right in such country, (b) the expiration of regulatory exclusivity, and (c) the date that is 10 years after the first commercial sale of such Licensed Product in such country. Potential future payments for variable consideration, such as regulatory and commercial milestones, development costs, and profit sharing U.S. Territory will be recognized when it is probable that, if recorded, a significant reversal will not take place. Potential future royalty payments will be recorded as revenue when the associated sales occur. Unless earlier terminated, the Chiesi Collaboration Agreement will remain in force until no Licensed Products are being developed or commercialized in the U.S. Territory and in the ROW Territory, on a country-by-country basis, until no royalty terms are in effect for all countries. Either party may terminate the Chiesi Collaboration Agreement for the other party’s material breach, subject to a specified notice and cure periods, or due to an insolvency event of the other party. In lieu of termination upon a party’s material breach due to non-payment of development costs within a specified time the non-breaching party may elect an alternative remedy which may involve modifications to their performance and payment obligations. The Company has the right to terminate by providing written notice in the event Chiesi or its affiliates or sublicensee brings a patent challenge and Chiesi does not take certain steps to withdraw from or cease supporting such challenge. Chiesi may terminate the Chiesi Collaboration Agreement without cause upon prior written notice to the Company, subject to a notice period in which all rights to Licensed Products will revert back to the Company. The Company concluded that progress towards completion of the research and development services performance obligation related to the Chiesi Collaboration Agreement is best measured in an amount proportional to the collaboration expenses incurred and the total estimated collaboration expenses. The Company periodically reviews and updates the estimated collaboration expenses, when appropriate, which may adjust revenue recognized for the period. While such changes to the Company’s estimates have no impact on the Company’s reported cash flows, the amount of revenue recorded in the period could be materially impacted. The transaction price to be recognized as revenue from sale of licenses and revenue from contracts with collaborators under the Chiesi Collaboration Agreement consists of the one-time non-refundable and non-creditable development cost reimbursement payment and research and development costs. The transaction price was reduced by the fair value of the Equity Option. Revenue Recognition The Company determined the transaction price pursuant to the Chiesi Collaboration Agreement is equal to the one-time development cost reimbursement payment of $ 160.0 million less the fair market value of the Equity Option of $ 0.5 million. The price allocated for the Equity Option was determined to be at fair market value utilizing the Geometric Brownian Motion/Monte Carlo model and was considered a reduction in the transaction price. The transaction price was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each distinct performance obligation. In estimating the stand-alone selling price for each distinct performance obligation, the Company developed assumptions that require judgment and included forecasted revenues or costs, expected development timelines, discount rates and probabilities of technical and regulatory success. A description of the distinct performance obligations identified under the Chiesi Collaboration Agreement, as well as the amount of revenue allocated to each distinct significant performance obligation, is as follows: Licenses of Intellectual Property . The licenses to the Company’s intellectual property, bundled with the associated know-how, represents two distinct performance obligations. The licenses and associated know-how were transferred to Chiesi in June 2024, therefore the Company recognized the full revenue related to F-29 Table of Contents these distinct performance obligations in the amount of $ 90.7 million during the year ended December 31, 2024 as revenue from sale of licenses on its consolidated statements of operations and comprehensive loss. Research and Development Services . The progress towards completion of two distinct performance obligations related to PAH and PH-ILD research and development services for the Licensed Products is measured in an amount proportional to the research and development expenses incurred and the total estimated PAH and PH-ILD research and development expenses. In addition, the Company and Chiesi share equally in the costs of ongoing global seralutinib clinical development, with the exception of the PROSERA Phase 3 study, and the costs of commercialization in the US. The Company records the revenue from performing research and development services and the cost-sharing payments due from Chiesi as revenue from contracts with collaborators on its consolidated statements of operations and comprehensive loss. For the years ended December 31, 2025 and 2024, the Company recognized $ 42.3 million and $ 23.5 million, respectively, for the PAH and PH-ILD research and development performance obligations. For the years ended December 31, 2025 and 2024, the Company recognized $ 6.2 million and $ 0.7 million, respectively, for the PAH and PH-ILD commercial planning activities. Milestone Payments . The Company determined that as of December 31, 2025, it is not probable that a significant revenue reversal will not occur related to the potential milestone payments as their achievement is highly dependent on factors outside the Company's control or are otherwise constrained under the sales and usage based royalty exception. Therefore, these payments have been fully constrained and are therefore not included in the transaction price. At the end of each subsequent reporting period, the Company will re-evaluate the probability of achievement of each milestone and any related constraint. No milestone payments were recognized during the year ended December 31, 2025. Royalties . As the licenses are deemed to be the predominant item to which sales-based royalties relate, the Company will recognize revenue when the related sales occur. No royalty revenue was recognized during the year ended December 31, 2025. The following table presents a summary of the activity in the Company's contract liabilities related to the Chiesi Collaboration Agreement (recorded as contract liabilities on the balance sheet) during the year ended December 31, 2025 and 2024 (in thousands): Balance, December 31, 2023 $ — Payments received in advance 159,536 Revenue from sale of US license ( 78,947 ) Revenue from sale of ROW license ( 11,721 ) Revenue from PAH research and development service performance obligations satisfied during reporting period ( 9,555 ) Revenue from PH-ILD research and development service performance obligations satisfied during reporting period ( 1,291 ) Effect of exchange rate changes on contract liabilities ( 2,103 ) Balance, December 31, 2024 55,919 Revenue from PAH research and development service performance obligations satisfied during reporting period ( 9,436 ) Revenue from PH-ILD research and development service performance obligations satisfied during reporting period ( 3,311 ) Effect of exchange rate changes on contract liabilities 6,421 Balance, December 31, 2025 $ 49,593 As of December 31, 2025, the contract liability amount of $ 49.6 million represents the aggregate transaction price allocated to performance obligations that are unsatisfied under the Chiesi Collaboration Agreement. This amount is expected to be recognized over 3.0 years, which represents the remaining research period under the Chiesi Collaboration Agreement. As of December 31, 2025, the current contract liability balance of $ 20.0 million is classified as a current liability since the rights to the research and development service are expected to be satisfied within one year, and the remaining contract liability balance of $ 29.6 million is classified as a long-term liability. As of December 31, 2025, the Company recorded $ 12.2 million in accounts receivable associated with the Chiesi Collaboration Agreement. The payments are typically due 30 days after quarterly invoices are issued. The following table presents the Company's contract revenues from the Chiesi Collaboration Agreement disaggregated by timing of revenue recognition and excluding royalty revenue (in thousands): F-30 Table of Contents Year ended December 31, 2025 2024 Revenue from Chiesi Collaboration Agreement: Point in Time: US License $ — $ 78,947 ROW License — 11,721 Over Time: Revenue from PAH research and development service performance obligation satisfied during reporting period 9,436 9,555 Revenue from PH-ILD research and development service performance obligation satisfied during reporting period 3,311 1,291 Revenue from PAH research and development costs subject to reimbursement 15,999 10,246 Revenue from PH-ILD research and development costs subject to reimbursement 13,578 2,380 Revenue from PAH commercial costs subject to reimbursement 5,554 538 Revenue from PH-ILD commercial costs subject to reimbursement 665 116 Effect of exchange rate changes on revenue ( 72 ) ( 93 ) Total revenue from Chiesi Collaboration Agreement $ 48,471 $ 114,701 Note 13 - Segment Information Operating segments are identified as components of an enterprise for which separate discrete financial information is available for evaluation by the CODM in making decisions regarding the allocation of resources and assessing performance. The Company's CODM is its chief executive officer. The Company views its operations and manages its business as one operating segment. The Company's operating segment derives its revenues from the Chiesi Collaboration Agreement. The CODM assesses performance for the Company's single operating segment and decides how to allocate resources based on research and development expenses incurred, which is a component of the Company's consolidated net loss as reported on the consolidated statement of operations and comprehensive loss. The measure of segment assets is reported on the balance sheet as total consolidated assets. Further, segment depreciation expense and segment asset additions are consistent with consolidated amounts reported within the consolidated statement of cash flows given the Company's operations are aggregated within a single reportable segment. The CODM uses research and development expenses and results of clinical trial activities completed to date to evaluate how to allocate the Company's resources to advance seralutinib. Significant segment expenses which are regularly reported to the CODM for purposes of making decisions regarding the allocation of resources are included within the table below and are reconciled to consolidated net loss: Year Ended December 31, 2025 2024 2023 (in thousands) Total revenue $ 48,471 $ 114,701 $ — Less: Seralutinib 173,635 129,247 103,158 Other segment items (1) 45,564 45,373 80,601 Interest income ( 1,970 ) ( 1,779 ) ( 1,997 ) Interest expense 10,989 11,517 13,511 Other income, net ( 9,289 ) ( 14,022 ) ( 15,456 ) Income tax expense ( 88 ) 893 — Segment net loss $ ( 170,370 ) $ ( 56,528 ) $ ( 179,817 ) (1) Other segment items include general and administrative expenses, which are provided to the CODM regularly, but are included within other segment items as they are not utilized as part of the decision making process as it relates to the allocation of resources. Further, R&D expenses for other terminated programs are also provided to the CODM. These costs include employee expenses, as well as allocations of consolidated overhead and stock compensation. Other segment items also include IPR&D expense related to the acquisition of the Respira Merger Option. F-31 Table of Contents Note 14 - Investments in Variable Interest Entities The Company reviews its investments in other entities to determine whether the Company is the primary beneficiary of a variable interest entity ("VIE"). The Company would be the primary beneficiary of the VIE and would be required to consolidate the VIE, if it has the power to direct the significant activities of the entity and the obligation to absorb losses or receive benefits from the entity that may be significant to the VIE. On September 24, 2025, the Company entered into an option agreement with Prana Bio, Inc. (“Prana”) to acquire Prana and its wholly-owned subsidiary, Respira Therapeutics, Inc. The Company identified Prana as a VIE but does not consolidate Prana as the Company lacks the power to direct the activities that significantly impact the economic success of Prana. Pursuant to the agreement, the Company issued 2,500,000 shares of its common stock as consideration for the option grant and agreed to issue up to an additional 1,500,000 shares of common stock following the exercise of the option. Concurrent with the option agreement, the Company entered into a research funding agreement with Prana whereas the Company agreed to provide up to a total of $ 7.8 million to Respira to carry out chemistry, manufacturing, and controls (“CMC”) activities related to Respira’s RT234 drug program. The Merger Option was valued at $ 7.5 million based on the value of the 2,500,000 shares of common stock issued using the Company's share price as of September 24, 2025, which was $ 2.99 per share of common stock. The option value was recognized as IPR&D expense in the Company's consolidated statements of operations and comprehensive loss. The Company does not consolidate Respira as the Company lacks the power to direct the activities that significantly impact the economic success of Respira. The Company's maximum loss exposure to Prana, prior to the exercise of the option to acquire, is limited to the Merger Option and cost reimbursements for certain research and development activities, which will be recognized as research and development expenses in the Company's consolidated statements of operations and comprehensive loss as incurred. Note 15 - Subsequent events The Company has evaluated all subsequent events and transactions through the filing date. On March 15, 2026, and in accordance with the terms of the 2019 Plan, the Company's board of directors (the "Board") approved a stock option repricing (the “2026 Option Repricing”) whereby the exercise price of each Eligible Option (as defined below) will be immediately reduced to the closing stock price on March 19, 2026. For purposes of the 2026 Option Repricing, “Eligible Options” with respect to the 2026 Option Repricing are 48,725,528 outstanding stock options as of March 17, 2026 (vested or unvested) granted under the 2019 Plan and held by those eligible employees of the Company identified by the Board, including the Company’s executive officers. Except for the reduction in the exercise prices of the Eligible Options as described above, the Eligible Options will retain their existing terms and conditions as set forth in the 2019 Plan and the applicable award agreements. On March 16, 2026, we commenced a workforce reduction of 77 individuals, constituting approximately 48 % of our workforce, to reduce our operating expenses. Our remaining management and employees will continue the development of seralutinib and explore potential regulatory paths forward. This workforce reduction is expected to be substantially completed by the end of May 2026. F-32 EXHIBIT INDEX Exhibit Number Exhibit Description Incorporated by Reference Filed Herewith Form Date Number 3.1 Amended and Restated Certificate of Incorporation. 10-Q 8/8/2023 3.1 3.2 Amended and Restated By laws . 8-K 11/27/2023 3.1 4.1 Form of Common Stock Certificate. S-1/A 1/23/2019 4.1 4.2 Description of Securities Registered under Section 12 of the Exchange Act. 10-K 2/26/2021 4.3 4.3 Indenture, dated as of May 21, 2020, by and between the Registrant and Wilmington Trust, National Association. 8-K 5/21/2020 4.1 4.4 First Supplemental Indenture, dated May 21, 2020, by and between the Registrant and Wilmington Trust, National Association. 8-K 5/21/2020 4.2 4.5 Form of Global Note representing 5.00% Convertible Senior Notes due 2027 (included as part of Exhibit 4.5). 8-K 5/21/2020 4.3 4.6 Form of Warrant. 8-K 7/20/2023 4.1 10.1# Gossamer Bio, Inc. 2017 Equity Incentive Plan, as amended. S-1 12/21/2018 10.1 10.2# Form of stock option grant notice and stock option agreement under Gossamer Bio, Inc. 2017 Equity Incentive Plan, as amended. S-1 12/21/2018 10.2 10.3# Form of restricted stock grant notice and restricted stock agreement under Gossamer Bio, Inc. 2017 Equity Incentive Plan, as amended. S-1 12/21/2018 10.3 10.4# Form of Founder restricted stock grant notice and restricted stock agreement. S-1 12/21/2018 10.4 10.5# Gossamer Bio, Inc. 2019 Incentive Award Plan , as amended and restated . DEF 14A 4/29/2025 Appendix A 10.6# Gossamer Bio, Inc. Performance Stock Unit Agreement under the 2019 Equity Incentive Plan 10-Q 11/5/2025 10.1 10.7# Gossamer Bio, Inc. 2019 Employee Stock Purchase Plan. S-1/A 1/23/2019 10.6 10.8# Gossamer Bio, Inc. Non-Employee Director Compensation Program. 10-K 3/13/2025 10.7 10.9# Gossamer Bio, Inc. Restricted Stock Unit Agreement under the 2019 Equity Incentive Plan. 10-Q 5/12/2020 10.1 10.10# Gossamer Bio, Inc. 2023 Employment Inducement Incentive Award Plan and Form of Stock Option Agreement thereunder. 8-K 11/27/2023 10.1 10.11# Letter Agreement, dated November 16, 2020, by and between Faheem Hasnain and the Registrant. 10-K 2/26/2021 10.11 10.12# Employment Letter, dated December 4, 2018, by and between Bryan Giraudo and the Registrant. S-1 12/21/2018 10.10 10.13# Employment Letter, dated December 4, 2018, by and between Christian Waage and the Registrant. S-1 12/21/2018 10.11 10.14# Employment Letter, dated April 16, 2021, by and between Caryn Peterson and the Registrant. 10-Q 8/9/2021 10.1 10.15# Employment Letter, dated June 21, 2021, by and between Richard Aranda and the Registrant. 10-Q 8/9/2021 10.3 10.16# Employment Letter, dated November 25, 2023, by and between Robert Smith and the Registrant. 10/K 3/5/2024 10.15 10.17# Form of Indemnification Agreement. S-1 12/21/2018 10.14 10.18† Exclusive License Agreement, dated October 2, 2017, by and between GB002, Inc., the Registrant and Pulmokine, Inc. S-1 12/21/2018 10.17 10.19 Stock Purchase Agreement, dated July 12, 2022, by and among the Registrant and the Purchasers named therein. 8-K 7/13/2022 10.1 10.20 Securities Purchase Agreement, dated July 19, 2023, by and among the Registrant and the Purchasers named therein. 8-K 7/20/2023 10.1 10.21# Form of Option Repricing and Cancellation Agreement. 10-Q 8/8/2023 10.1 10.22 † Collaboration and License Agreement dated May 3, 2024 by and among GB002, Inc., Gossamer Bio 002 Ltd. and Gossamer Bio, Inc. on the one hand and CHIESI Farmaceutici S.p.A and CHIESI USA, Inc. on the other hand. 10-Q 8/12/2024 10.1 19.1 Gossamer Bio, Inc. Insider Trading Compliance Policy and Procedures 10-K 3/13/2025 19.1 Exhibit Number Exhibit Description Incorporated by Reference Filed Herewith Exhibit Number Form Date Number 21.1 List of Subsidiaries of the Registrant. X 23.1 Consent of I ndependent R egistered P ublic A ccounting F irm. X 31.1 Certification of Chief Executive Officer of Gossamer Bio, Inc., as required by Rule 13a-14(a) or Rule 15d-14(a) under the Securities Exchange Act of 1934, as amended. X 31.2 Certification of Chief Financial Officer of Gossamer Bio, Inc., as required by Rule 13a-14(a) or Rule 15d-14(a) under the Securities Exchange Act of 1934, as amended. X 32.1* Certification of Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. X 32.2* Certification of Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. X 97 Policy for Recovery of Erroneously Awarded Compensation . 10-K 3/5/2024 97 101.INS XBRL Report Instance Document X 101.SCH XBRL Taxonomy Extension Schema Document X 101.CAL XBRL Taxonomy Calculation Linkbase Document X 101.DEF XBRL Taxonomy Extension Definition Linkbase Document X 101.LAB XBRL Taxonomy Label Linkbase Document X 101.PRE XBRL Presentation Linkbase Document X 104 Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101) X # Indicates management contract or compensatory plan. † Portions of this exhibit (indicated by asterisks) have been omitted for confidentiality purposes pursuant to Item 601(b)(10)(iv) of Regulation S-K. * These certifications are being furnished solely to accompany this annual report pursuant to 18 U.S.C. Section 1350, and are not being filed for purposes of Section 18 of the Securities Exchange Act of 1934 and are not to be incorporated by reference into any filing of the Registrant, whether made before or after the date hereof, regardless of any general incorporation language in such filing. SIGNATURES Pursuant to the requirements of Section 13 or 15(d) 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. GOSSAMER BIO, INC. By: /s/ Faheem Hasnain Faheem Hasnain President and Chief Executive Officer Date March 17, 2026 SIGNATURES AND POWER OF ATTORNEY Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated. Signature Title Date /s/ Faheem Hasnain President, Chief Executive Officer and Chairman of the Board of Directors (principal executive officer) March 17, 2026 Faheem Hasnain /s/ Bryan Giraudo Chief Operating Officer and Chief Financial Officer (principal financial and accounting officer) March 17, 2026 Bryan Giraudo /s/ Russell Cox Director March 17, 2026 Russell Cox /s/ Thomas Daniel, M.D. Director March 17, 2026 Thomas Daniel, M.D. /s/ Sky Drynan Director March 17, 2026 Sky Drynan /s/ Sandra Milligan, M.D., J.D. Director March 17, 2026 Sandra Milligan, M.D., J.D. /s/ Steven Nathan, M.D. Director March 17, 2026 Steven Nathan, M.D. /s/ John Quisel, J.D., Ph.D. Director March 17, 2026 John Quisel, J.D., Ph.D.