Gossamer Bio, Inc.

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 asone operating segment. The 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, generallytwo toseven 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 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 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.

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.

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 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):

Note 3—Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):

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):

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.

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):

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):

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 intwo additional tranches

(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 hasno 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 thefive 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 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):

The following table sets forth the interest expense recognized related to the 2027 Notes (in thousands):

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 often 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):

Note 7—Income Taxes

The amount of net loss before taxes for the years ended December 31, 2025, 2024, and 2023 is as follows:

A reconciliation of income tax expense (benefit) for the years ended December 31, 2025, 2024 and 2023 is as follows:

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.

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:

(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:

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.

A reconciliation of the beginning and ending amount of unrecognized tax benefits for 2025, 2024, and 2023, excluding interest and penalties, is as follows:

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 toone 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 offive 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 vesting period as compensation expense. As of December 31, 2025, there wereno 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 theten-year term of the 2019 Plan, beginning 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 firstten 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, andno 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 iszero 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 theone-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 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:

The following table summarizes stock option activity for the years ended December 31, 2025, 2024 and 2023:

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 wereno 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.

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:

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:

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):

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):

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 wasimmaterial.

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 aone-year extension and an option to terminate on December 1, 2027 with the payment of a termination fee equal tofour 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):

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):

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 grantedtwo 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

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.

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, representstwo 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 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 oftwo 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):

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):

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 asone 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:

(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.

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.

EXHIBIT INDEX