Instil Bio, Inc.

Notes to Consolidated Financial Statements

1. Organization and Description of Business

Instil Bio, Inc. (the “Company”) is a biotechnology company focused on identifying and advancing innovative therapeutic opportunities.

In January 2026, the Company announced that its wholly owned subsidiary, Axion Bio, Inc. (“Axion Bio”), was discontinuing development of AXN-2510/IMM2510, its former lead product candidate.

The Company is actively seeking to in-license or acquire and develop additional novel therapeutic candidates in diseases with significant unmet medical need.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying consolidated financial statements include but are not limited to the fair value of assets held for sale and determination of fair value of the Company’s building, and stock-based compensation. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could differ from those estimates.

Concentration of Credit Risk

Financial Instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash, and marketable securities. The Company’s cash and cash equivalents are held bytwo financial institutions in the United States (“U.S.”) andone financial institution in the United Kingdom (“UK”), which management believes to be financially sound, and accordingly, minimal credit risk exists with respect to the financial institutions. At times, the Company’s deposits held in the U.S. and UK may exceed the Federal Depository Insurance Corporation and Financial Services Compensation Scheme, respectively, insured limits. During the years ended December 31, 2025 and 2024, the Company has not experienced any credit losses in such accounts or marketable securities.

Risks and Uncertainties

The Company is subject to a number of risks similar to other development-stage biopharmaceutical companies, including but not limited to, the Company’s ability to acquire or in-license promising product candidates, dependency on the clinical and commercial success of such product candidates, if any, ability to obtain regulatory approval of any product candidates, uncertainty of broad adoption of its approved products, if any, by physicians and patients, manufacturing, the need to obtain adequate additional funding, significant competition, and protection of its intellectual property portfolio.

Segments

Operating segments are identified as components of an entity for which separate discrete financial information is available and that is regularly reviewed by the chief operating decision maker, the Company’s Chief Executive Officer, in deciding how to allocate resources to an individual segment and in assessing performance. The Company has determined it operates in a single operating segment and hasone operating segment. See Note 3 for further information.

Cash, Cash Equivalents, Restricted Cash, and Marketable Securities

The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents include amounts invested in money market accounts.

Restricted cash consists of a cash reserve which served as collateral for the Company’s Construction Loans (as defined in Note 8) during the year ended December 31, 2024. As of December 31, 2025, restricted cash consists of a cash reserve allocated to future tax payments. There was $0.2 million and $1.8 million restricted cash as of December 31, 2025 and 2024, respectively, on the consolidated balance sheets.

The Company’s investments in marketable securities have been classified and accounted for as available-for-sale. The Company classifies its maturities as either short-term or long-term based on each instrument’s underlying contractual maturity date, which are carried at their fair values based on the quoted market prices of the securities. Unrealized gains and losses are reported as accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale securities are included in net loss in the period earned or incurred. As of December 31, 2025 and 2024, marketable securities consisted of U.S. Treasury bills.

The Company periodically reviews whether its securities may be other-than-temporarily impaired, including whether or not (i) the Company has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the security before its anticipated recovery. If one of these factors is met, the Company will record an impairment loss associated with its impaired investment. The impairment loss will be recorded as a write-down of investments in the consolidated balance sheets and a realized loss within other expense in the consolidated statements of operations and comprehensive loss. For the years ended December 31, 2025 and 2024, there were no impairment losses for the investments.

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the amounts shown in the consolidated statements of cash flows (in thousands):

Going Concern

The accompanying consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Management evaluated the Company’s ability to continue as a going concern for the twelve months following the issuance of the consolidated financial statements. As disclosed and defined in Note 8, the 2024 Loan is due in January 2027, for total principal of $85.6 million which is in excess of cash, cash equivalents, and marketable securities on hand as of December 31, 2025, which management has concluded is an indicator of substantial doubt about the Company's ability to continue as a going concern.

If the Company is unable to refinance the 2024 Loan prior to maturity, the Company plans to execute its contractual right to extend the maturity of the 2024 Loan to January 2028. In addition to the Company’s plan to exercise the extension option in the 2024 Loan, the Company may seek to refinance or restructure the 2024 Loan including by extending its maturity date beyond the extended date, sell the building to repay the 2024 Loan, or seek additional financing in the form of equity or debt instruments. There can be no assurance that new financing or other forms of funding will be available on favorable terms or at all. Management concluded that the Company’s contractual right to exercise the extension option to January 2028 is solely within the Company’s control and alleviates the conditions that raise substantial doubt about the Company’s ability to continue as a going concern.

Fair Value Measurement

Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value maximize the use of observable inputs and minimize the use of unobservable inputs. The Company measures fair value based on a three-tier hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows:

Level 1 —Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.

Level 2 —Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the assets or liabilities. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active.

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

In determining fair value, the Company utilize quoted market prices, or valuation techniques that maximize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value.

Property, Plant and Equipment, Net

Property, plant and equipment, with the exception of land, is stated at cost less accumulated depreciation. Depreciation is computed on a straight-line basis over the estimated useful lives of the related assets. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the consolidated balance sheets and the resulting gain or loss is reflected in the consolidated statements of operations and comprehensive loss. The estimated useful lives of the Company’s property, plant and equipment are as follows:

The Company owns land and building and, as described in Note 4, the clinical and commercial manufacturing building has been completed and has been leased. See Note 8 for details. In March 2025, the Company’s board of directors(the“Board of Directors”) approved a plan to sell the Tarzana facility. The Company engaged a broker to facilitate the sale of the Tarzana facility and therefore reclassified the land and building as held for sale in the consolidated balance sheet as of December 31, 2025. Refer to Note 4.

Assets Held for Sale

The Company classifies long-lived assets or disposal groups to be sold as held for sale in the period in which all of the following criteria are met: management, having the authority to approve the action, commits to a plan to sell the asset or disposal group; the asset or disposal group is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such assets or disposal group; the sale of the asset or disposal group is probable, and transfer of the asset or disposal group is expected to qualify for recognition as a completed sale within one year, except if events or circumstances beyond the Company’s control extend the period of time required to sell the asset or disposal group beyond one year; and actions required to complete the plan to sell have been initiated.

The Company initially measures a long-lived asset or disposal group that is held for sale at the lower of its carrying value or fair value less any costs to sell. Fair value is estimated by the Company through evaluations of quoted market prices received for other comparable held for sale assets sold by the Company. Any loss resulting from this measurement is recognized in the period in which the held for sale criteria are met. Conversely, gains are not recognized on the sale of a long-lived asset or disposal group until the date of sale. The Company assesses the fair value of a long-lived asset or disposal group less any costs to sell each reporting period it remains classified as held for sale and reports any subsequent changes as an adjustment to the carrying value of the asset or disposal group, as long as the new carrying value does not exceed the carrying value of the asset at the time it was initially classified as held for sale. Upon determining that a long-lived asset or disposal group meets the criteria to be classified as held for sale, the Company ceases depreciation and reports long-lived assets in the line item “assets held for sale” in its consolidated balance sheets.

In March 2025, the Company’s Board of Directors approved a plan to sell the Tarzana facility. The Company engaged a broker to facilitate the sale of the Tarzana facility and therefore reclassified the land and building as held for sale in the consolidated balance sheet as of December 31, 2025. The Tarzana facility is currently leased to AstraZeneca Pharmaceuticals LP (“Tenant”) and Tenant has a right of first offer to purchase it. Refer to Note 8. During the year ended December 31, 2025, the Company recorded a building impairment related to the Tarzana facility of $16.6 million. During the year ended December 31, 2024, the Company recorded non-cash impairment charges for assets held for sale related to impairment of the Company’s Manchester, United Kingdom manufacturing equipment of $4.3 million recognized in the consolidated statements of operations and comprehensive loss in the line item “restructuring and impairment charges.” See Note 4 for more information.

Impairment of Long-Lived Assets

The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable or that the useful life is shorter than originally estimated. Recoverability of assets is measured by comparing the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset over its remaining useful life. If such assets are impaired, the impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. If the useful life is shorter than originally estimated, the Company depreciates or amortizes the remaining carrying value over the revised shorter useful life. During the year ended December 31, 2025 the Company recognized an impairment of long-lived assets held for sale related to the Tarzana facility of $16.6 million. During the year ended December 31, 2024, the Company recorded non-cash impairment charges for assets held for sale related to impairment of the Company’s Manchester, United Kingdom manufacturing equipment of $4.3 million.

The Company recognized non-cash impairment charges ofnil and $0.3 million for the years ended December 31, 2025 and 2024, respectively, related to impairment of leasehold improvements.

These non-cash impairment charges were recorded in the consolidated statements of operations and comprehensive loss in the line item “restructuring and impairment charges.” See Note 13 for more information.

Research and Development Expenses

Research and development costs are expensed as incurred. Clinical trial and other development costs incurred by third parties are expensed as the contracted work is performed. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or project and the invoices received from its external service providers. The Company adjusts its accrual as actual costs become known. Where contingent milestone payments are due to third parties under research and development arrangements or license agreements, the milestone payment obligations are expensed when the milestone results are achieved.

Stock-Based Compensation

The Company measures its stock-based awards granted to employees, non-employee directors, consultants and independent advisors based on the estimated grant date fair value of the awards. For stock-based awards with only service conditions, compensation expense is recognized over the requisite service period using the straight-line method. For stock-based awards that include performance conditions, compensation expense is not recognized until the performance condition is probable to occur. The Company uses the Black-Scholes option pricing model to estimate the fair value of its stock-based awards. The Black-Scholes option pricing model requires the Company to make assumptions and judgements about the variables used in the calculations, including the fair value of common stock, expected term, expected volatility of the Company’s common stock, risk-free interest rate and expected dividend yield. The Company accounts for forfeitures of stock-based awards as they occur.

Income Taxes

Income taxes are accounted for using the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts or existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period of enactment. The Company records a valuation allowance to reduce deferred tax assets to an amount expected to be realized.

The Company recognizes the tax benefit from an uncertain tax position if it is more likely than not that the tax position will be sustained upon examination by the tax authorities, based on the merits of the position. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.

Foreign Currency

The Company’s reporting currency is the U.S. dollar. The functional currency of the Company’s subsidiary located in the United Kingdom is the British pound sterling. Balance sheets prepared in the functional currency are translated to the reporting currency at exchange rates in effect at the end of the accounting period, except for stockholders’ deficit accounts, which are translated at rates in effect when these balances were originally recorded. Revenue and expense accounts are translated using an average exchange rate in effect during the period. The resulting foreign currency translation adjustments are recorded as a separate component of accumulated other comprehensive loss in the accompanying consolidated balance sheets.

Gains and losses resulting from exchange rate changes on intercompany transactions denominated in a currency other than the local currency are included in earnings as incurred as the related amounts are expected to be repaid in the foreseeable future.

Net Loss Per Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of the Company’s common stock outstanding for the period, without consideration for potential dilutive shares of common stock. For purposes of the diluted net loss per share calculation, convertible preferred stock and common stock options are considered to be potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented since the effects of potentially dilutive securities are antidilutive given the net loss of the Company.

Comprehensive Loss

Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. For the years ended December 31, 2025 and 2024, comprehensive loss consists of foreign currency translation adjustments and unrealized loss on available-for-sale securities net of tax.

Leases

The Company determines if an arrangement is or contains a lease at contract inception by assessing whether the arrangement contains an identified asset and whether the lessee has the right to control such asset. Lessees are required to classify leases as either finance or operating leases and to record a right-of-use (“ROU”) asset and a lease liability for all leases with a term greater than 12 months regardless of the lease classification. The lease classification will determine whether the lease expense is recognized based on an effective interest rate method or on a straight-line basis over the term of the lease. The Company determines the initial classification and measurement of its ROU assets and lease liabilities at the lease commencement date and thereafter if modified. For leases with a term greater than 12 months, the Company records the lease liability at the present value of lease payments over the term. The term of the Company’s leases equals the non-cancellable period of the lease, including any rent-free periods provided by the lessor, and also includes options to extend or terminate the lease that the Company is reasonably certain to exercise. The ROU asset equals the carrying amount of the related lease liability, adjusted for any lease payments made prior to lease commencement, any deferred rent upon adoption, and lease incentives provided by the lessor.

The Company has elected, for all classes of underlying assets, not to recognize ROU assets and lease liabilities for leases with a term of 12 months or less. Lease cost for short-term leases is recognized on a straight-line basis over the lease term. The Company estimates its incremental borrowing rate based on 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.

Variable lease payments are expensed as incurred and do not factor into the measurement of the applicable ROU asset or lease liability. Lease payments may be fixed or variable; however, only fixed payments are included in the Company’s lease liability calculation. Lease costs for the Company’s operating leases are recognized on a straight-line basis within operating expenses over the lease term. The Company’s lease agreements may contain non-lease components such as common area maintenance, operating expenses or other costs, which are expensed as incurred for all classes of assets. The Company’s leases do not contain any residual value guarantees. See Note 8 for further information below.

Recent Accounting Pronouncements Adopted

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 annual periods beginning after December 15, 2025, with early adoption permitted. The Company adopted ASU 2023-09 for the year ended December 31, 2025, and applied the new disclosure requirements prospectively. The adoption of this standard did not have a material impact on the Company's consolidated financial statements and disclosures. For additional information, see Note 12.

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). The amendments in this update require disclosure, in the notes to the consolidated financial statements, of specific expense categories present within expense captions presented on the face of the income statement within continuing operations of public business entities. The amendments in this update are effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027. The Company is currently evaluating the impact of this ASU 2024-03 on its consolidated financial statements and related disclosures.

In September 2025, the FASB issued ASU No. 2025-07, Derivatives and Hedging and Revenue from Contracts with Customers - Derivatives Scope Refinements and Scope Clarification for Share-Based Noncash Consideration from a Customer in a Revenue Contract (“ASC 2025-07”) which applies to all entities that enter into non-exchange-traded contracts with underlyings based on operations or activities specific to one of the parties to the contract. The new guidance excludes from derivative accounting non-exchange-traded contracts with underlyings that are based on operations or activities specific to one of the parties to the contract. ASU 2025-07 is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods within those annual reporting periods. Early adoption is permitted. The Company does not expect adoption of ASU 2025-07 to have a material impact on its consolidated financial statements and related disclosures.

A variety of proposed or otherwise potential accounting standards are currently being studied by standard-setting organizations and certain regulatory agencies. Because of the tentative and preliminary nature of such proposed standards, the Company has not yet determined the effect, if any, that the implementation of such proposed standards would have on the Company’s consolidated financial statements.

3. Segment Reporting

The Company manages its business activities on a consolidated basis and hasone reportable segment relating to the research and development of its novel therapies. The Chief Executive Officer, who serves as the Company’s chief operating decision maker (“CODM”), is responsible for the overall supervision, direction, and management of the business and its officers.

The CODM reviews net loss, as reported in the consolidated statements of operations and comprehensive loss, as well as the progress of the Company’s program(s). The CODM does not review assets in evaluating the results of the segment, and therefore, such information is not presented. All long-lived assets owned by the Company are located the United States. The accounting policies of the segment are the same as those described in Note 2.

The following table is a summary of the segment loss, including significant segment expenses for the years ended December 31, 2025 and 2024 (in thousands):

(1) Depreciation expense is removed from both “General and administrative” and “Other program expense” and is disclosed separately.

(2) Other program expenses consist of costs related to the Company’s past development of its CoStAR-TIL technology.

4. Balance Sheet Components

Prepaid and other current assets

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

Property, Plant and Equipment, Net

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

Depreciation expense was $0.5 million and $3.6 million for the years ended December 31, 2025 and 2024, respectively, in the consolidated statements of operations and comprehensive loss.

As of December 31, 2025, the Company had $112.1 million in assets related to the Tarzana facility on the consolidated balance sheet meeting the criteria of held for sale assets. These assets are recognized at the lower of cost or fair value less costs to sell. The Company estimates the fair value of the Tarzana facility through a combination of an income-based approach and a market-based approach. The income-based approach is dependent on specific assumptions such as market rental rates, capitalization rates and discount rates. The market-based approach utilizes observable data such as comparable building sales. The fair value of these assets are classified as Level 3 in the fair value hierarchy due to a mix of unobservable inputs utilized such as proprietary independent research in the market as well as actual quotes from market participants. The Company recognized impairment of $16.6 million andnil related to the Tarzana facility during the years ended December 31, 2025 and 2024, respectively.

The Company recognized non-cash impairment charges ofnil and $4.3 million related to United Kingdom equipment impairments during the years ended December 31, 2025 and 2024, respectively.

Accrued Expenses and Other Current Liabilities

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

5. Fair Value Measurement

The fair value of cash and cash equivalents approximates carrying value since cash and cash equivalents consist of short-term highly liquid investments with maturities of less than three months at the time of purchase. Cash and cash equivalents are valued based upon quoted market prices in active markets for identical assets and are therefore classified as Level 1 assets. Money market funds are open-end mutual funds that invest in cash, government securities, and/or repurchase agreements that are collateralized fully. To the extent that these funds are valued based upon the reported net asset value, they are categorized in Level 1 of the fair value hierarchy.

Short-term marketable securities consisted of U.S. Treasury bills that are classified within Level 2 of the fair value hierarchy are valued based on other observable inputs, including broker or dealer quotations, alternative pricing sources or U.S. Government Treasury yield of appropriate term.

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring and nonrecurring basis:

There were no transfers in or out of Level 1, 2 and 3 measurements for the years ended December 31, 2025 and 2024. As of December 31, 2025 and 2024, there were no securities within Level 3 of the fair value hierarchy. As of December 31, 2024, the contingent consideration was within Level 3 of the fair value hierarchy.

As of December 31, 2025 and 2024, the fair value of the 2024 Loan (as defined in Note 8) was $85.5 million and $84.7 million, respectively. The fair value was determined on the basis of its net present value and is considered Level 2 in the fair value hierarchy.

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands):

The Company’s acquisition of Immetacyte involved the potential for the payment of future contingent consideration upon the achievement of (i) certain product development milestones including, approval of studies and commencement and completion of certain product trials, or (ii) various other performance conditions including, receipt of final approval for the first marketing authorization and first commercial sale in certain geographical markets. Contingent consideration is recorded at the estimated fair value of the contingent payments on the acquisition date. The fair value of the contingent consideration is remeasured at the estimated fair value at each reporting period with the change in fair value recognized as income or expense within research and development expense in the consolidated statements of operations and comprehensive loss.

During the year of acquisition, the Company determined the fair value of the contingent consideration by probability weighting scenarios of milestone achievements to determine the expected future contingent consideration payment, discounted to present value using an 8% discount rate based on the Company’s pre-tax cost of debt on the acquisition date. The probability of payments was 0% and 5% as of December 31, 2025 and 2024, respectively. Determinations of the likelihood of milestone achievements, which trigger payouts related to the contingent consideration, as well as the probabilities for various scenarios used in the Company’s calculations, were based on internal unobservable projections.

During the years ended December 31, 2025 and 2024, the change in fair value related to the contingent consideration was due to the discontinuation of the ITIL-306-202 development program, the change in present value for the passage of time, as well as expected dates and probabilities of milestone achievement revisions.

6. Financial Instruments

Marketable securities classified as available-for-sale on December 31, 2025 and 2024 consisted of the following (in thousands):

As of December 31, 2025 and 2024, marketable securities that had contractual maturities less than one year are classified as current because management considers these marketable securities to be available for current operations. The Company does not intend to sell its marketable securities and it is not likely that the Company will be required to sell these securities before recovery of their amortized cost basis. There were $69.5 million and $104.5 million of marketable securities classified as available-for-sale as of December 31, 2025 and December 31, 2024, respectively.

7. License and Collaboration Agreement with ImmuneOnco

On August 1, 2024, Axion Bio entered into the license and collaboration agreement with ImmuneOnco (the “IO Collaboration Agreement”). As part of this agreement, Axion Bio made a $10.0 million upfront payment to ImmuneOnco during the year ended December 31, 2024. This amount was fully expensed as in-process research and development (IPR&D) in the same year.

During the year ended December 31, 2024, Axion Bio made a $5.0 million prepayment to ImmuneOnco for development costs, which was fully expensed in research and development as of March 31, 2025. A second $5.0 million prepayment for development costs was made to ImmuneOnco in April 2025, which was fully expensed in research and development as of September 30, 2025. A third $5.0 million prepayment to ImmuneOnco for development costs was made in August 2025. This amount was partially expensed under research and development, with a remaining prepaid balance of $0.3 million recorded as of December 31, 2025.

In June 2025, Axion Bio achieved Investigational New Drug (IND) clearance in the United States for a Phase 1 trial of AXN-2510 in relapsed/refractory solid tumors. This milestone triggered a $10.0 million development payment to ImmuneOnco, which was paid in July 2025. This amount was fully expensed as IPR&D during the second quarter of 2025.

The expenses recognized in connection with the IO Collaboration Agreement were $23.8 million and $10.0 million for the year ended December 31, 2025 and 2024, respectively, and were recorded as a component of research and development expense on the consolidated statements of operations and comprehensive loss. As of December 31, 2025, no additional milestones had been accrued as the underlying contingencies had not yet been resolved.

Under the IO Collaboration Agreement, ImmuneOnco was eligible to receive additional potential near-term payments of up to $15.0 million, up to $2.1 billion in commercial, development and regulatory milestones (including up to $270.0 million in longer term development and regulatory milestones and up to $1.8 billion in commercial milestones) plus single-digit to low double-digit percentage royalties on global net sales of the licensed products outside of Greater China. On January 5, 2026, Axion Bio and ImmuneOnco entered into an agreement terminating the IO Collaboration Agreement. Under the termination agreement, Axion Bio agreed to transfer the rights, title, and interest related to AXN-2510 and AXN-27M to ImmuneOnco, and ImmuneOnco agreed to pay Axion Bio $1.8 million.

8. Commitments and Contingencies

Leases

Company as a Lessee: Operating Lease Obligations

The Company currently leases office spaces and laboratory spaces located in Dallas, Texas and Alderley Park in the United Kingdom. During April 2025, the Company terminated its prior lease in Thousand Oaks, California. The Company’s leased facilities have original lease terms ranging from 2 to 5 years that in general require the Company to provide a security deposit. Certain leases provide the right for the Company to renew the lease upon the expiration of the initial lease term, and various leases have scheduled rent increases on an annual basis. The exercise of lease renewal options for the Company’s existing leases is at the Company’s sole discretion, and not included in the measurement of right-of-use asset or lease liability as they are not reasonably certain to be exercised.

The Company’s lease costs consisted of the following (in thousands):

The following table summarizes cash flow information related to the Company’s lease obligations (in thousands):

The following table summarizes the Company’s lease assets and liabilities (in thousands):

The following table summarizes other supplemental information related to the Company’s lease obligations:

Future minimum lease payments under operating lease liabilities were $0.4 million as of December 31, 2025 which are recorded in the line item“accrued expenses and other current liabilities” in the consolidated balance sheet.

During the years ended December 31, 2025 and 2024, the Company evaluated its remaining right-of-use assets for impairment, as the Plan (as defined below in Note 13) has resulted in a cessation of use for the United Kingdom locations. The Company determined these assets were impaired and recognized animpairment loss ofnil and $0.8 million for the years ended December 31, 2025 and 2024, respectively, which are recorded in the line item “restructuring and impairment charges” in the consolidated statements of operations and comprehensive loss.

Company’s Subsidiary as a Lessor: Tarzana Facility Lease with AstraZeneca

On July 10, 2024, Complex Therapeutics LLC, a wholly owned subsidiary of the Company, entered into a lease with AstraZeneca Pharmaceuticals LP (“Tenant”) pursuant to which Tenant is leasing the facility located in Tarzana, California (the “Lease”). The Lease has an initial term of approximately 15 years, beginning on July 10, 2024 and ending on July 31, 2039, with Tenant havingtwo consecutive options to extend the term for afive-year period each and a one-time option to terminate the Lease on the tenth anniversary of the commencement of the Lease, which, if exercised, obligates Tenant to pay Complex Therapeutics LLC a termination fee. The initial base rent was approximately$0.6 million per month (approximately$7.5 million annually) and the base rent escalates by 3% per annum. Tenant is also required to pay certain operating expenses and tax expenses as additional rent. There was rent abatement during the first year of the Lease such that Tenant paid no rent or reduced rent during this period. Tenant also has a right of first offer to purchase the premises that are subject to the Lease.

The Lease is classified as an operating lease and revenue is recognized on a straight-line basis and is recorded within the consolidated statements of operations and comprehensive loss in the line item “Other rental income” as this is not a part of the Company’s core operations. Rental income related to the Lease was as follows (in thousands):

Approximate future straight-lined contractual lease income to be recognized under the lease in effect as of December 31, 2025 is as follows (in thousands):

Differences between rental income earned and amounts due per the Lease is capitalized or charged, as applicable, to accrued rent receivable. As of December 31, 2025 and December 31, 2024, the Company had accrued rent receivable of $7.7 million and $4.3 million, respectively.

Legal Proceedings

From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and that such expenditures can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. The Company does not expect that the resolution of these matters will have a material adverse effect on its financial position, results of operations or cash flows.

Debt

In June 2022, the Company’s wholly owned subsidiaries, Complex Therapeutics Mezzanine LLC and Complex Therapeutics LLC entered into a mortgage construction loan and mezzanine construction loan (together, the “Construction Loans”) secured by Complex Therapeutic LLC's Tarzana, California land and building. The initial principal amount of the Construction Loans was $52.1 million, with additional future principal of up to $32.9 million to fund ongoing construction costs. The Construction Loans were guaranteed by the Company and bore interest at the one-month Secured Overnight Financing Rate, plus 5.25% per annum. On July 10, 2024, Complex Therapeutics LLC entered into the Lease. On December 20, 2024, Complex Therapeutics LLC refinanced the outstanding principal amount under the Construction Loans and the Company treated it as a loan extinguishment for accounting purposes and recorded the $0.4 million of unamortized debt issuance costs associated with the Construction Loans as a loss on debt extinguishment recognized in other expense, net in the consolidated statements of operations and comprehensive loss for the year ended December 31, 2024.

On December 20, 2024, Complex Therapeutics LLC entered into a Term Loan Agreement (the “2024 Loan”) and related loan documents with Midland National Life Insurance Company (“Midland”), pursuant to which Midland loaned Complex Therapeutics LLC a term loan in the principal amount of $85.6 million to refinance the Construction Loans. Substantially all of the 2024 Loan proceeds were used to repay in full the Construction Loans. As of December 31, 2025, the outstanding principal amount under the 2024 Loan was $85.6 million and unamortized debt issuance costs were $0.8 million.

The 2024 Loan has a term oftwo years with aone-year extension option. The extension option is subject to certain conditions being met, including: (a) no potential default or event of default, (b) payment of a 0.35% extension fee and the costs and expenses of Midland incurred in connection with the extension, (c) replenishing of all reserve funds as reasonably determined by Midland, and (d) compliance with minimum debt yield and debt service coverage ratio requirements. The 2024 Loan bears interest at a fixed rate of 6.35% per annum, with interest-only payments during the term of the 2024 Loan and the principal balance due in full at maturity. The Company expects Complex Therapeutics LLC to meet all requirements necessary to exercise the extension.

The 2024 Loan may be prepaid in whole but not in part. If the 2024 Loan is prepaid on or prior to the 12-month anniversary of the Closing Date, a prepayment fee is required (other than in connection with a casualty or condemnation event) to make Midland whole for the interest it would have otherwise earned on the 2024 Loan during the first 12 months. There is no prepayment fee due if the 2024 Loan is prepaid after the 12-month anniversary of the Closing Date.

The net carrying amount of the liability component of the 2024 Loan was as follows (in thousands):

The following table sets forth the interest expense recognized related to the 2024 Loan and Construction Loans (in thousands):

Indemnifications

The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. The Company currently has directors’ and officers’ insurance coverage that reduces its exposure and enables the Company to recover a portion of any future amounts paid. No liability associated with such indemnifications was recorded as of December 31, 2025 and 2024.

Other Commitments

In the normal course of business, the Company enters into contracts and various purchase agreements and commitments with third-party vendors for clinical research services, products and other services for operating purposes. These agreements generally provide for termination or cancellation at the Company's option, other than for costs already incurred.

As of December 31, 2025 and 2024, the Company hadnil and $0.1 million outstanding liabilities, respectively, in commitments for employee benefits as part of the Plan (see Note 13). As of December 31, 2025 and 2024, the Company had $0.2 million and $1.9 million, respectively, in commitments for contract terminations as part of the Plan. (see Note 13).

The Company entered into an agreement in 2023 with a third-party collaborator in China related to the development of the Company’s CoStAR-TIL technology; this agreement was subsequently terminated in 2025. Milestone payments ofnil and $2.6 million were made during the year ended December 31, 2025 and 2024, respectively, and were recorded within research and development expense in the consolidated statements of operations and comprehensive loss.

9. Equity

Common Stock

Each share of common stock has the right toone vote. The holders of common stock are also entitled to receive dividends out of legally available funds when and if declared by the Company’s Board of Directors, subject to the rights of holders of any classes of stock outstanding having priority rights as to dividends. No cash dividends have been declared by the Board of Directors from inception.

As of December 31, 2025 and 2024, the Company had 6,781,976 and 6,525,887 shares of common stock outstanding, respectively.

At-the-Market Offering (ATM Program)

In March 2025, the Company entered into an Open Market Sale Agreement SM with Jefferies LLC (“Jefferies”) pursuant to which the Company may, subject to the terms and conditions set forth in the agreement, offer and sell, from time to time, through or to Jefferies, acting as agent or principal, shares of common stock having an aggregate offering price of up to $100.0 million in one or more “at the market offerings” (the “ATM Program”).

During the year ended December 31, 2025, the Company sold 185,837 shares of common stock under the ATM Program at a weighted-average price of $37.13 per share, for net proceeds of $6.6 million, after deducting commissions and expenses of approximately $0.3 million. The remaining availability under the ATM Program as of December 31, 2025 is approximately $93.1 million.

Preferred Stock

The Company’s current amended and restated certificate of incorporation authorizes the Company to issue up to 10,000,000 shares of preferred stock at $0.000001 par value per share. The Board of Directors is authorized to provide for the issuance of the preferred stock in one or more series, and to fix the number of shares and to determine or alter for each such series, such voting powers, full or limited, or no voting powers, and such designation, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in subsequent resolution or resolutions adopted by the board providing for the issuance of such shares. As of December 31, 2025 and 2024 there wereno shares of preferred stock issued or outstanding.

10. Stock-Based Compensation

2021 Equity Incentive Plan

In March 2021, the Company adopted the 2021 Equity Incentive Plan (the “2021 Plan”), which became effective in connection with the Company’s initial public offering (“IPO”). The 2021 Plan was approved by the Board of Directors and stockholders in March 2021. The 2021 Plan is an equity incentive plan pursuant to which the Company may grant the following awards: (i) incentive stock options; (ii) nonstatutory stock options; (iii) stock appreciation rights; (iv) restricted stock awards; (v) restricted stock unit awards; (vi) performance awards; and (vii) other forms of stock awards to employees, directors, and consultants, including employees and consultants of the Company’s affiliates. The 2021 Plan is a successor to the Company’s 2018 Stock Incentive Plan (the “2018 Plan”). Following the effectiveness of the 2021 Plan, no further grants may be made under the 2018 Plan; however, any outstanding equity awards granted under the 2018 Plan will continue to be governed by the terms of the 2018 Plan.

The number of shares available for future issuance under the 2021 Plan is the sum of (1)433,000 new shares of common stock, (2)209,722 remaining shares of common stock reserved under the 2018 Plan that became available for issuance upon the effectiveness of the 2021 Plan and (3) the number of shares of common stock subject to outstanding awards under the 2018 Plan when the 2021 Plan became effective that thereafter expire or are forfeited, canceled, withheld to satisfy tax withholding or to purchase or exercise an award, repurchased by the Company or are otherwise terminated. The number of shares of common stock reserved for issuance under the 2021 Plan will automatically increase on January 1 of each year, for a period often years, from January 1, 2022 continuing through January 1, 2031, by 5% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares as may be determined by the Company’s Board of Directors. Stock options granted by the Company to employees generally vest over four years with aone-year cliff.

As of December 31, 2025,481,355 shares of common stock remained available for issuance under the 2021 Plan.

The following table sets forth stock-based compensation included in the Company's consolidated statements of operations and comprehensive loss (in thousands):

The aggregate intrinsic value disclosed in the above table is based on the difference between the exercise price of the stock option and the estimated fair value of the Company’s common stock as of the respective period-end dates. There were 70,252 and 21,974 stock options exercised during the years ended December 31, 2025 and 2024, respectively. The aggregate intrinsic value of stock options exercised waszero and $0.1 million during the years ended December 31, 2025 and 2024, respectively. The weighted-average grant date fair value of stock options granted during the years ended December 31, 2025 and 2024, was $14.13 and $22.85 per share, respectively.

The following table sets forth stock-based compensation included in the Company’s consolidated statements of operations and comprehensive loss (in thousands):

As of December 31, 2025 and 2024, there was $12.6 million and $16.6 million, respectively, of total unrecognized compensation cost related to unvested stock options granted under the 2018 Plan and 2021 Plan, which is expected to be recognized over a weighted average period of 2.35 years and 2.25 years, respectively.

The fair value of the Company’s stock option awards was estimated at the date of grant using a Black-Scholes option pricing model with the following assumptions:

The Black-Scholes option pricing model requires the use of highly subjective assumptions which determine the fair value of stock-based awards. These assumptions include:

Expected term—The expected term represents the period that stock-based awards are expected to be outstanding and is determined as the average of the time-to-vesting and the contractual life of the awards.

Expected volatility—Since the Company is privately held and does not have any trading history for its common stock, the expected volatility was estimated based on the average volatility for comparable publicly traded biotechnology companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on their similar size, stage in the life cycle or area of specialty.

Risk-free interest rate—The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of awards.

Expected dividend yield—The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield ofzero.

Employee Stock Purchase Plan

In March 2021, the Company adopted the Employee Stock Purchase Plan (the “ESPP”), which became effective in connection with the IPO. The ESPP was adopted by the Board of Directors and stockholders in March 2021, but the Company has not yet commenced offerings to employees under the ESPP. The ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 61,850 shares of common stock. The number of shares reserved under the ESPP automatically increases on January 1 of each year through and until January 1, 2031, in an amount equal to the lesser of (i)1% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, and (ii)123,700 shares; provided, however, that before the date of any such increase, the Board of Directors may determine that such increase will be less than the amount set forth in clauses (i) and (ii).

11. Net Loss Per Share

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:

12. Income Taxes

The geographical breakdown of loss before provision for income taxes is as follows (in thousands):

The Company had no income tax expense for both domestic and foreign jurisdictions for the years ended December 31, 2025 and 2024.

A reconciliation of the provision for income taxes to the amount computed by applying the 21% statutory U.S. federal income tax rate to income before income taxes after the adoption of ASU 2023-09 is as follows (in thousands, except percentages):

A reconciliation of the provision for income taxes to the amount computed by applying the 21% statutory U.S. federal income tax rate to income before income taxes for the year prior to the adoption of ASU 2023-09 is as follows:

The components of deferred tax liabilities consist of the following (in thousands):

The components of unrecognized tax benefits consist of the following (in thousands):

In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Due to the uncertainty of the business in which the Company operates, projections of future profitability are difficult and past profitability is not necessarily indicative of future profitability. The Company does not believe it is more likely than not that the deferred tax assets will be realized, and accordingly, the valuation allowance increased $12.5 million for the year ended December 31, 2025. As of December 31, 2025, the Company had net operating loss carryforwards for federal income tax purposes of $405.4 million, which will carryforward indefinitely, but may only offset 80% of the Company’s taxable income. This limitation on the net operating loss may require the Company to pay federal income taxes in future years despite generating a loss for federal income tax purposes in prior years. In addition, the Company has $136.1 million of California net operating loss carryforwards available to reduce future state taxable income as of the year ended December 31, 2025. The state net operating loss carryforwards will begin to expire, if not utilized, in 2044.

The Company has R&D credits of $4.1 million, and $3.7 million for federal and California, respectively, as of December 31, 2025. The federal R&D credits expire in 2043 and the California R&D credits carryforward indefinitely.

Upon the prospective adoption of ASU 2023-09 the Company is required to disclose income taxes paid, net of refunds for 2025. All amounts for federal, state and foreign arezero for the year ended December 31, 2025.

The Company files income tax returns in the U.S. federal jurisdiction, various states where the Company has employees and/or significant business activities, and the United Kingdom. As of December 31, 2025, the Company’s federal and state returns through 2022 are still open to examination. The UK returns starting from 2024 are open to examination. The Company had uncertain tax positions as of December 31, 2024 of $2.3 million and this balance remained unchanged during December 31, 2025. The Company does not anticipate that the amount of existing unrecognized tax benefits will significantly increase or decrease during the next 12 months. The Company had no accrued interest or penalties related to uncertain tax positions as of December 31, 2025.

The Company has not completed a Section 382 study to assess whether an ownership change has occurred or whether there have been multiple ownership changes since the Company’s formation. Pursuant to Internal Revenue Code Sections 382 and 383, annual use of the Company’s net operating loss and research and development tax credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period. Due to the existence of the valuation allowance, limitations created by future ownership changes, if any, are not anticipated to impact the Company’s effective tax rate.

13. Corporate Restructuring Plan

In January 2023, the Board of Directors approved a restructuring plan (referred to as the “2023 Plan”) and the Company announced the consolidation of the ITIL-306 Phase 1 clinical trial and related manufacturing of CoStAR-TIL to its operations in Manchester, UK and stopped recruiting for the ITIL-306 clinical trial.

In January 2024, the Board of Directors approved a comprehensive restructuring plan, which included the closure of the Company’s UK manufacturing facility and clinical trial operations. In September 2024, the Board of Directors approved additional UK restructuring actions, which resulted in the elimination of the majority of the remaining UK workforce in the fall of 2024, with the remaining reduction and restructuring activities substantially completed by the end of 2024. Collectively, these actions are referred to as the “2024 Plan.”

The 2023 Plan and 2024 Plan are collectively referred to as the “Plan”.

As a result of the Plan and listing the Tarzana facility for sale, the Company recorded charges of $16.6 million and $7.5 million within the consolidated statements of operations and comprehensive loss in the line item “restructuring and impairment charges” for the years ended December 31, 2025 and 2024, respectively.

These charges relate to asset impairments, contract terminations, severance payments, employee-related costs and other gains incurred. The following table summarizes the restructuring and impairment (gain) loss by category (in thousands):

Restructuring Liability

As a result of the Plan, the restructuring liability was recorded in the consolidated balance sheets under “Accrued expenses and other current liabilities” and was measured at the amount expected to be paid, or that was paid. During the year ended December 31, 2025, the Company paid $1.4 million of restructuring costs, and expects to pay the remainder of the restructuring costs by December 31, 2026.

The following table shows the liability related to the Plan (in thousands):