CytomX Therapeutics, Inc.

1. Descriptionof the Business

CytomX Therapeutics, Inc. (the “Company”) is a clinical-stage, oncology-focused biopharmaceutical company developing potent biologics designed to remain masked and inactive in healthy tissue and to be unmasked and preferentially activated in the tumor microenvironment. The Company aims to build a commercial enterprise to maximize its impact on the treatment of cancer. The Company is advancing potential first-in-class and best-in-class therapeutics created using its PROBODY® therapeutic technology platform that could meaningfully improve outcomes for cancer patients. Its proprietary and unique PROBODY technology platform is designed to enable “conditional activation” of masked drug candidates in the tumor microenvironment across multiple therapeutic modalities. The Company is located in South San Francisco, California and was incorporated in the state of Delaware in September 2010.

2. Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation

The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).

Use of Estimates

The preparation of the financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates.

Concentration of Credit Risk and Other Risks and Uncertainties

The Company is subject to a number of risks similar to other biopharmaceutical companies in the early stage, including, but not limited to, the need to obtain adequate additional funding, possible failure of preclinical testing or clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of the Company’s products, and protection of proprietary technology. If the Company does not successfully obtain regulatory approval, commercialize or partner any of its product candidates, it will be unable to generate revenue from product sales or achieve profitability.

Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, short-term investments and accounts receivable. Substantially all the Company’s cash is held by one financial institution. Such deposits may, at times, exceed federally insured limits. The Company invests its cash equivalents in highly rated money market funds and its short-term investments in U.S. Treasury securities.

Cash, Cash Equivalents and Restricted Cash

The Company considers all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents. Restricted cash represents a standby letter of credit issued pursuant to office leases and value added tax return.

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

Investments

All investments have been classified as available-for-sale (“AFS”) and are carried at fair value as determined based upon quoted market prices or pricing models for similar securities at period end. Investments that are required for use in current operations and that mature in less than 12 months are classified as short-term investments in the accompanying balance sheets. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold.

The Company assesses impairment of its AFS debt securities investments at each reporting period. Unrealized gains resulting from the excess of the fair value over the amortized cost basis of an investment are reported as a component of accumulated other comprehensive income (loss), net of tax. Unrealized losses or impairments resulting from the fair value of the AFS debt security being below the amortized cost basis are evaluated, using the discounted cash flow model, for identification of credit losses and non-credit related losses. Any credit losses are charged to earnings against the allowance for credit losses of the security, limited to the difference between the fair value and the amortized cost basis of the security. Any difference between the fair value of the security and the amortized cost basis, less the allowance for credit losses, are reported in other comprehensive income (loss). Expected cash inflows due to improvements in credit are recognized through a reversal of the allowance for credit losses subject to the total allowance previously recognized. Interest receivable of $0.5 million and $22 thousand as of December 31, 2025 and 2024, respectively, primarily related to short term investments are included in prepaid expenses and other current assets.

In the event of impairment of any security, if management (i) has the intent to sell such security or (ii) will more-likely-than-not be required to sell such security before recovery of its amortized cost basis, such AFS debt security’s amortized cost basis will be written down to its fair value through earnings along with any existing allowance for credit losses.

Property and Equipment, net

Property and equipment are recorded at cost net of accumulated depreciation and amortization. Depreciation is provided using the straight-line method over the estimated useful lives of the respective assets. The useful lives of property and equipment are as follows:

Maintenance and repairs that do not extend the life or improve the asset are expensed when incurred.

Goodwill and Intangible Assets

Goodwill represents the excess of the purchase price paid over the fair value of tangible and identifiable intangible assets acquired in business combinations. Goodwill and other intangible assets with indefinite lives are not amortized, but are assigned to reporting units and tested for impairment annually, or whenever there is an impairment indicator. Intangible assets are comprised of in-process research and development. The Company assesses impairment indicators annually as of December 31 or more frequently, if a change in circumstances or the occurrence of events suggests the remaining value may not be recoverable. Intangible assets that are not deemed to have an indefinite life are amortized over their estimated useful lives. There wasno impairment of goodwill or intangible assets identified during the years ended December 31, 2025 and 2024.

Impairment of Long-Lived Assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset (or asset group) may not be recoverable and prior to any goodwill impairment test. An impairment loss is recognized when the total of estimated undiscounted future cash flows expected to result from the use of the asset (or asset group) and its eventual disposition is less than its carrying amount. Impairment, if any, would be assessed using discounted cash flows or other appropriate measures of fair value. During the years ended December 31, 2025 and 2024, the Company recorded impairment loss of $0.4 million and $0.1 million for long-lived assets.

Revenue Recognition

The Company’s revenues are primarily derived through its license, research, development and commercialization agreements. The terms of these types of agreements may include (i) licenses for the Company’s technology or programs, (ii) research and development services, and (iii) services or obligations in connection with participation in research or steering committees. Payments to the Company under these arrangements typically include one or more of the following: nonrefundable upfront and license fees, research funding, milestone and other contingent payments to the Company for the achievement of defined collaboration objectives and certain preclinical, clinical, regulatory and sales-based events, as well as royalties on sales of any commercialized products.

The Company assesses whether the promises in its arrangements with customers are distinct performance obligations that should be accounted for separately. Judgment is required to determine whether the license to the Company’s intellectual property is distinct from the research and development services or participation on steering committees.

The Company’s collaboration and license agreements may include contingent payments related to specified research, development and regulatory milestones. Such milestone payments are typically payable under the collaborations when the collaboration partner claims or selects a target, or initiates or advances a covered product candidate in preclinical or clinical development, upon submission for marketing approval of a covered product with regulatory authorities, or upon receipt of actual marketing approvals of a covered product or for additional indications. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At each reporting date, the Company re-evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price by using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price in such period of determination.

The Company’s collaboration and license agreements may also include contingent payments related to sales-based milestones. Sales-based milestones are typically payable when annual sales of a covered product reach specified levels. Sales-based milestones are recognized at the later of when the associated performance obligation has been satisfied or when the sales occur. Unlike other contingency payments, such as regulatory milestones, sales-based milestones are not included in the transaction price based on estimates at the inception of the contract; instead, they are included when the sales or usage occur.

The transaction price in each arrangement is allocated to the identified performance obligations based on the relative standalone selling price (“SSP”) of each distinct performance obligation, which requires judgment. In instances where SSP is not directly observable, such as when a license or service is not sold separately, SSP is determined using information that may include market conditions and other observable inputs. Due to the early stage of the Company’s licensed technology, the license of such technology is typically combined with research and development services and steering committee participation as one performance obligation. In the event that the Company receives non-cash consideration such as consideration in the form of a research license and research support services from the counterparty, the transaction price of a non-monetary exchange that has commercial substance is estimated based on the fair value of the non-cash consideration received, which may be determined through a valuation analysis.

In certain cases, the Company’s performance creates an asset that does not have an alternative use to the customer and the Company has an enforceable right to payment at all times for performance completed to date. In these cases, 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. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Most of the company's collaboration arrangements are related to delivering a combined performance obligation satisfied over time. Revenue is recognized over the estimated research period using an input measure based on the actual full-time employee (“FTE”) hours incurred as a percentage of projected FTE hours for completing the performance obligation. There have been changes in estimates of research service periods and/or the related estimated FTE hours-to-completion of certain of its research development programs in each reporting period. Such adjustment is accounted for on a prospective basis in the Company's revenue recognition. Changes in the estimated research service periods resulted in recognition of higher total revenue of $13.8 million for 2025 as compared to the estimated research service periods in place at the end of 2024, and a decrease of net loss per share by $0.10 for 2025.

Any consideration payable to the Company’s customers is treated as a reduction to the transaction price and revenue, unless the payment to the customer is in exchange for distinct good and services.

Comprehensive Income (Loss)

Comprehensive income (loss) represents all changes in stockholders’ equity (deficit) except those resulting from distributions to stockholders. The Company’s non-credit related unrealized gains and losses on investments during the period represent the component of other comprehensive income (loss) that is excluded from the reported net loss.

Contract Balances

Customer payments are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company satisfies its performance obligations under these arrangements. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional.

The Company records accrued liabilities for estimated costs of research and development activities conducted by third-party service providers, which include the conduct of preclinical and clinical studies, and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced, and includes these costs in accrued liabilities in the balance sheets and within research and development expense in the statements of operations. These costs are a significant component of the Company’s research and development expenses. The Company accrues for these costs based on factors such as estimates of the work completed and in accordance with agreements established with its third-party service providers under the service agreements. The Company makes judgments and estimates in determining the accrued liabilities balance in each reporting period. As actual costs become known, the Company adjusts its accrued liabilities. The Company has not experienced any material differences between accrued costs and actual costs incurred. However, the status and timing of actual services performed may vary from the Company’s estimates, resulting in adjustments to expense in future periods. Changes in these estimates that result in material changes to the Company’s accruals could materially affect the Company’s results of operations.

Research and development expenses include costs directly attributable to the conduct of research and development programs, including the cost of salaries, payroll taxes, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, the cost of services provided by outside contractors, and the allocated portions of facility costs, such as rent, utilities, insurance, repairs and maintenance, depreciation, and general support services. All costs associated with research and development are expensed as incurred.

Stock-based Compensation

The Company measures compensation expense for all stock-based payment awards, including employee stock options, restricted stock units (“RSUs”), and employee stock purchases related to Employee Stock Purchase Plan (“ESPP”) based on estimated fair values of the award at the grant date, and recognizes compensation expense over the requisite service vesting period. Stock option forfeitures are accounted for in the period in which they occur.

To determine the fair value of a stock option award on the grant date, the Company uses the Black-Scholes option pricing model which consist of estimating variables such as the following. These estimates involve inherent uncertainties and the application of judgment.

Expected term. The expected term of stock options represents the period that the stock options are expected to remain outstanding and is based on the Company's historical exercise experience with previously issued employee and board of directors' option grants. The expected term of the ESPP shares is equal to the six-month look-back period.

Expected volatility. The expected stock price volatility for the Company’s stock options is based on the historical stock price volatility which is commensurate with the estimated expected term of the stock awards. Volatility for ESPP shares is equal to the Company’s historical volatility over a six-month offering period.

Risk-free interest rate. The risk-free interest rate is based on the U.S. Treasury yield with a maturity equal to the expected term of the stock options in effect at the time of grant.

Dividend yield. The expected dividend is assumed to be zero as the Company has never paid dividends and has no current plan to pay any dividends on its common stock.

The Company measures its restricted stock unit awards based on the market price of the Company’s common shares on the date of grant. Share-based compensation expense for performance-based awards is recognized when it becomes probable that the performance condition will be met. The Company reassesses the estimated probability at each reporting period, and if it is determined at a future date that a performance condition is probable of being achieved, the Company will recognize a cumulative catch-up adjustment and record the remaining expense ratably over the remaining requisite service period.

Income Taxes

The Company accounts for income taxes using an asset and liability approach. Deferred tax assets and liabilities reflect the net tax effects of temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using 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 Company records a valuation allowance to reduce its deferred tax assets to reflect the net amount that it believes as more likely than not to be realized. Realization of the deferred tax assets is dependent on the generation of future taxable income, the amount and timing of which are uncertain. The valuation allowance requires an assessment of both positive and negative evidence when determining whether it is more likely than not that deferred tax assets are recoverable. Based upon the weight of available evidence at December 31, 2025, the Company continues to maintain a full valuation allowance against all of its deferred tax assets.

The Company recognizes the tax effects of an uncertain tax position only if it is more likely than not that it will be sustained based solely on its technical merits as of the reporting date and only in an amount more likely than not that it will be sustained upon review by the tax authorities. The Company evaluates uncertain tax positions on a quarterly basis and adjust the liability for changes in facts and circumstances, such as new regulations or interpretations by the taxing authorities, new information obtained during a tax examination, significant amendment to an existing tax law, or resolution of an examination. To the extent that the final tax outcome of these matters is different than the amounts recorded, such differences will impact the income tax provision in the period in which such determination is made. The resolution of its uncertain income tax positions is dependent on uncontrollable factors such as law changes, new case law, and the willingness of the income tax authorities to settle, including the timing thereof and other factors. Interest and/or penalties related to income tax matters are recognized as a component of income tax expense.

Leases

The Company determines if an arrangement is or contains a lease at inception. Operating leases are recorded as operating lease right-of-use (“ROU”) assets and operating lease liabilities in the Company’s balance sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The Company uses an implicit rate when readily available, or its incremental borrowing rate based on the information available at lease commencement date in determining the present value of lease payments. The operating lease ROU assets also include any lease prepayments made and reduced by lease incentives. The Company’s lease terms may include options to extend the lease when it is reasonably certain that such option will be exercised. Lease expenses are recognized on a straight-line basis over the lease term. The Company elected the short-term lease recognition exemption. The Company’s operating lease arrangement includes lease and non-lease components which are accounted for as a single lease component. The non-lease components generally refer to common area maintenance (“CAM”) charges related to the premises.

Recent Accounting Pronouncements

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09"), which enhances transparency in income tax disclosures. ASU 2023-09 requires entities to disclose (1) specific categories in the rate reconciliation, (2) the income or loss from continuing operations before income tax expense or benefit (separated between domestic and foreign) and (3) income tax expense or benefit from continuing operations (separated by federal, state and foreign). ASU 2023-09 also requires entities to disclose their income tax payments to international, federal, state and local jurisdictions, among other changes. The Company has adopted this ASU as of December 31, 2025 on a prospective basis.

In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2024-03, Disaggregation of Income Statement Expenses (“ASU 2024-03”), which enhances transparency in income statement disclosures. ASU 2024-03 requires entities to disclose detailed information about specific components of income statement expenses, such as employee compensation, depreciation, and amortization, as well as other significant expense categories. The objective is to provide financial statement users with greater insight into the nature and variability of expenses, improving their ability to analyze financial performance and make informed decisions. ASU 2024-03 is effective for the annual reporting periods beginning after December 15, 2026 and for interim periods within annual reporting periods beginning after December 15, 2027 with early adoption permitted. The Company expects to adopt this ASU during the year ended December 31, 2027 on a prospective basis and is currently evaluating the impact on its financial statements.

3. Net Income (Loss) Per Share

Basic net income (loss) per share is calculated by dividing the net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period. Diluted net income (loss) per share is calculated using the weighted-average number of common shares outstanding, plus potential dilutive common stock during the period. Diluted net loss per share is the same as basic net loss per share in the period when the effect of the potentially dilutive securities is anti-dilutive. The pre-funded warrants were included in both the basic and diluted EPS calculation.

The following table presents the calculation of basic and diluted net income (loss) per share:

The following weighted-average outstanding shares of potentially dilutive securities are excluded from the computation of diluted net loss per share for the periods presented, because including them would have been anti-dilutive:

4. Fair Value Measurements and Investments

The Company determines the fair value of financial and non-financial assets and liabilities using the fair value hierarchy, which establishes three levels of inputs that may be used to measure fair value, as follows:

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Level I: Inputs which include quoted prices in active markets for identical assets and liabilities.

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Level II: Inputs other than Level I that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

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

The carrying amounts of the Company’s financial instruments, including restricted cash, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. The Company’s financial instruments consist of Level I and Level II assets which consist primarily of highly liquid money market funds, some of which are included in restricted cash and U.S. Treasury securities that are included in short-term investments. Our Level II marketable securities are valued using third-party pricing sources, which can include observable market prices, interest rates and yield curves observable at commonly quoted intervals for similar assets as observable inputs for pricing.

The following tables set forth the fair value of the Company’s investments subject to fair value measurements on a recurring basis and the level of inputs used in such measurements:

As of December 31, 2025, the remaining contractual terms of the U.S. Treasury securities are less than a year. Based on the scheduled maturities of our marketable securities, we determined that it was more likely than not that we will hold these marketable securities to maturity for a recovery of our cost basis.

5. Property and Equipment

Property and equipment, net consisted of the following:

Depreciation and amortization expense was $1.2 million and $1.6 million for the years ended December 31, 2025 and 2024, respectively.

6. Intangible Asset

The intangible asset is being amortized over the estimated lives of the patents which average 12 years. The amortization expense for each of the years ended December 31, 2025 and 2024 was $0.1 million.

7. Accrued Liabilities

Accrued liabilities consisted of the following:

8. Collaboration and License Agreements

The following table summarizes the revenue by collaboration partner:

Amgen, Inc.

On September 29, 2017, the Company and Amgen, Inc. (“Amgen”) entered into a Collaboration and License Agreement (the “Amgen Agreement”). Pursuant to the Amgen Agreement, the Company received an upfront payment of $40.0 million in October 2017. Concurrent with the Amgen Agreement, the Company and Amgen entered into a Share Purchase Agreement pursuant to which Amgen purchased 1,156,069 shares of the Company’s common stock at a price of $17.30 per share for total proceeds of $20.0 million.

Under the terms of the Amgen Agreement, as amended, the Company and Amgen were co-developing a conditionally activated T-cell engager (“TCE”) targeting epidermal growth factor receptor (the “EGFR Products”). The Company was responsible for early-stage development of EGFR Products and Amgen was to be responsible for late-stage development and commercialization of EGFR Products. Following potential advancement beyond early-stage development, the Company had the right to elect to participate financially in the global co-development of EGFR Products with Amgen, during which the Company would have been responsible for a certain percentage of the worldwide development costs and entitled to certain percentage of profit sharing in the U.S., for EGFR Products. In addition, the Company was also eligible to receive up to $460.0 million in development, regulatory, and commercial milestone payments for EGFR Products, and royalties in certain percentages of worldwide commercial sales.

In October 2021, CytomX and Amgen executed an amendment to the Amgen Agreement primarily to (1) extend the target selection date for Amgen to select its additional targets for research and development, and (2) reduce the total number of milestone events and increase the total amount of milestone payments for EGFR Products. In each of May 2023 and March 2024, CytomX and Amgen executed an amendment to the Amgen Agreement to extend the target selection period for Amgen to select its additional targets.

Amgen had the right to select a total of up tothree targets, including the two additional targets. The Company and Amgen collaborated in the research and development of conditionally activated T-cell engaging bispecifics therapies directed against such targets. Amgen had selectedone such target (the “Amgen Other Product”). Except with respect to preclinical activities to be conducted by CytomX, Amgen would have been responsible, at its expense, for the development, manufacture, and commercialization of all Amgen Products. The Company concluded that, at the inception of the agreement and subsequent amendments, Amgen’s option to select thetwo additional targets is not a material right and does not represent a performance obligation of the agreement.

In January 2022, the IND for the EGFR product (“CX-904”) was allowed to proceed by the U.S. Food and Drug Administration (“FDA”) and the program progressed into Phase 1 dose escalation. In March 2025, CytomX and Amgen jointly decided to not continue CX-904 development and Amgen terminated its license to the EGFR Products. As a result, all of the remaining deferred revenue of the EGFR product was recognized in the first quarter of 2025 due to Amgen terminating its license to the EGFR Product effective May 2025. In April 2025, the Amgen Other Product was also terminated with 60 days written notice pursuant to the Amgen Agreement. The Amgen research collaboration remains in effect with the current scope being the preclinical TCE that CytomX selected from Amgen’s preclinical pipeline further discussed below.

At the initiation of the collaboration, CytomX had the option to select from programs specified in the Amgen Agreement, an existing preclinical stage TCE product from the Amgen preclinical pipeline. In March 2018, CytomX selected the program and this program, CX-908, a PROBODY® T cell engager targeting CDH3 and CD3, is currently in preclinical development. CytomX is responsible, at its expense, for converting this program to a conditionally activated TCE product, and thereafter, will be responsible for development, manufacturing, and commercialization of the product (“CytomX Product”). Amgen is eligible to receive up to $203.0 million in development, regulatory, and commercial milestone payments for the CytomX Product, and tiered mid-single digit to low double-digit percentage royalties.

The Company considered the criteria for combining contracts in ASC 606 and determined that the Amgen Agreement and the Purchase Agreement should be combined into one contract. The Company accounted for the Amgen Agreement based on the fair values of the assets and services exchanged.

For each of the EGFR Products and the Amgen Other Products, the Company determined that the respective promised goods and services identified, which are the research, development and commercialization license; the related research and development services and the participation in the joint steering committee and joint research committee, are not distinct. Therefore the identified promised goods and services were combined into one single performance obligation for each of the EGFR Product and the Amgen Other Products.

Furthermore, the Amgen Other Products are accounted for as a separate performance obligation from the EGFR Products as the nature of the services being performed is not the same and the value that Amgen can derive from one program is not dependent on the success of the other.

Concurrent with the execution of the Amgen Agreement, the Company entered into a sublicense agreement whereby the Company granted Amgen a sublicense of its rights to one patent family that it co-owns with UCSB, that is exclusively licensed to the Company under the UCSB Agreement covering certain conditionally activatable antibodies in the fields of therapeutics, in vivo diagnostics and prophylactics. This sublicense was incremental to the patents, patent applications and know-how covering conditionally activated T-cell engaging bispecific molecules that were developed and owned by the Company and licensed to Amgen. Under the UCSB Agreement, as amended, the Company is obligated to make a sublicense payment to UCSB equal to up to 7.5% of certain upfront and milestone payments owed to or received by the Company.

The total transaction price of $51.2 million, consisting of the $40.0 million upfront payment, an estimated fair value of $10.7 million for the CytomX Product and $0.5 million of premium on the sale of the Company’s common stock, was allocated between the two performance obligations based on the relative standalone selling price of each performance obligation. To determine the standalone selling price, the Company used the discounted cash flow method by calculating risk-adjusted net present values of estimated cash flows.

Of the $51.2 million total transaction price, the Company allocated $46.4 million to the EGFR Products performance obligation and $4.8 million to the Amgen Other Product performance obligations. The transaction price of each performance obligation was recognized using an input measure. In applying the input method of revenue recognition, the Company uses actual full-time employee (“FTE”) hours incurred relative to estimated total FTE hours expected to be incurred for each combined performance obligation over the research service period. The $4.8 million transaction price allocated to the Amgen Other Product performance obligation was recognized using estimated FTE hours-to-completion over the estimated research service period ofsix years.

The Company evaluates the measure of progress each reporting period using the input method and, if necessary, adjusts the measure of performance and related revenue recognition. As of June 30, 2025, the Company had completed its performance obligations related to the EGFR Products and the Amgen Other Products and recognized the remaining deferred revenue. As of December 31, 2024, deferred revenue related to the EGFR Products performance obligation was $9.7 million and was immaterial for the Amgen Other Products.

Astellas Pharma Inc.

The Company and Astellas Pharma, Inc. (“Astellas”) entered into a Collaboration and License Agreement (the “Astellas Agreement”) on March 23, 2020, the effective date, to collaborate on preclinical research activities to discover and develop certain antibody compounds for the treatment of cancer using the Company’s PROBODY therapeutic technology.

Under the terms of the Astellas Agreement, the Company granted Astellas an exclusive, worldwide right to develop and commercialize PROBODY therapeutics for up tofour collaboration targets includingone initial target andthree additional targets (“Additional Targets”). In addition, Astellas had the right to expand the number of Additional Targets from three up tofive (the “Expansion Option”) before the third anniversary of the effective date. Furthermore, for a specified number of targets, at a pre-specified time prior to the initiation of the first pivotal study of a product against such target, the Companyhad the option to elect to participate in certain development costs and share in the profits generated in the United States with respect to such product (“Cost Share Option”). The Cost Share Option, if exercised, also provided the option for the Company to co-commercialize such product in the United States. The Company had not considered the Cost Share Option as a performance obligation at the inception of the agreement as participation is at the Company’s discretion.

Pursuant to the Astellas Agreement, the consideration from Astellas was comprised of an upfront fee of $80.0 million and total potential contingent payments for development, regulatory and sales milestones of up to an aggregate of approximately $1.2 billion. The Company was also entitled to tiered royalties from high-single digit to mid-teen percentage royalties from potential future sales. Astellas was responsible for all preclinical research costs incurred by either party as set forth in the preclinical research plan and the Company was entitled to receive research and development service fees based on a prescribed FTE rate.

The Company had determined that the license and expertise related to the development of product candidates should be combined with the research and development services and participation in the joint research committee as one combined performance obligation for each collaboration target. The Company concluded, that at the inception of the agreement, Astellas’ Expansion Option for Additional Targets were not material rights and therefore not considered performance obligations. As such, each option would have been accounted for as a separate arrangement upon exercise.

The initial transaction price of $103.2 million consists of the upfront fee of $80.0 million and estimated research and development fees of $23.2 million. The transaction price was allocated between the four performance obligations based on the relative standalone selling price of each performance obligation, which was deemed to be equal at the inception of the agreement. The Company determined that all potential milestone payments are constrained as of December 31, 2025 due to the significant uncertainty of achievement.

The transaction price, as allocated to the combined performance obligation for each target, is recognized using an input measure. In applying the input method of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred over the estimated research service period of each target.

In January 2023, the Company achieved a clinical candidate milestone for the first collaboration target nomination under the Astellas Agreement which triggered a $5.0 million milestone payment to the Company which was fully recognized in the first quarter of 2023 as the Company had completed its related performance obligation. In March 2024, the Company achieved the good laboratory practices ("GLPs") toxicology milestone for this candidate which triggered a $5.0 million milestone payment to the Company. The $5.0 million milestone payment was fully recognized in the first quarter of 2024 as the Company had completed its related performance obligation of this first collaboration target. Also, in March 2024, the Company achieved a clinical candidate milestone for a second collaboration target nomination under the Astellas Agreement which triggered an additional $5.0 million milestone paymentto the Company. The$5.0 million milestone payment for this second nomination was fully recognized in the first quarter of 2024 as the Company had completed its related performance obligation. In the first quarter of 2025, Astellas initiated GLP toxicology studies for the second collaboration target, triggering a $5.0 million milestone payment to CytomX. The $5.0 million milestone payment was fully recognized in the first quarter of 2025 as the Company had completed its related performance obligation of this second collaboration target.

As of December 31, 2025 and 2024, deferred revenue relating to the Astellas Agreement was$8.6 million and$17.4 million, respectively. The amount due from Astellas under the Astellas Agreement was $0.9 million and $1.1 million as of December 31, 2025 and 2024, respectively. In the first quarter of 2026, Astellas chose not to advance the remaining preclinical programs which will result in the completion of CytomX’s performance obligation and recognition of the remaining deferred revenue by the second quarter of 2026.

Bristol Myers Squibb Company

On May 23, 2014, the Company and Bristol Myers Squibb Company (“Bristol Myers Squibb”) entered into a Collaboration and License Agreement (the “BMS Agreement”) to discover and develop compounds for use in human therapeutics aimed at multiple immuno-oncology targets using the Company’s PROBODY therapeutic technology, including the target CTLA-4. The effective date of the BMS Agreement was July 7, 2014.

Under the terms of the BMS Agreement, the Company granted Bristol Myers Squibb exclusive worldwide rights to develop and commercialize PROBODY therapeutics for up tofour oncology targets. Bristol Myers Squibb had additional rights to substitute up totwo collaboration targets within three years of the effective date of the BMS Agreement. These rights expired in May 2017. Each collaboration target had atwo-year research term and thetwo additional targets had to be nominated by Bristol Myers Squibb within five years of the effective date of the BMS Agreement. The research term for each collaboration target could be extended inone year increments up tothree times.

Pursuant to the BMS Agreement, the financial consideration from Bristol Myers Squibb was comprised of an upfront payment of $50.0 million and estimated research and development service fees, and the Company was initially entitled to receive contingent payments of up to $25.0 million for additional targets and contingent payments for development, regulatory and sales milestones. In addition, the Company was entitled to royalty payments in the mid-single digits to low double-digit percentages from potential future sales.

On March 17, 2017, the Company and Bristol Myers Squibb amended the BMS Agreement and entered into Amendment Number 1 to Extend Collaboration and License Agreement (“Amendment 1”). Amendment 1 granted Bristol Myers Squibb exclusive worldwide rights to develop and commercialize PROBODY therapeutics for up toeight additional targets. The effective date of Amendment 1 was April 25, 2017 (“Amendment Effective Date”). Under the terms of Amendment 1, the Company continued to have obligations to Bristol Myers Squibb to discover and conduct preclinical development of PROBODY therapeutics against any targets they chose to select during the research period under the terms of Amendment 1.

Pursuant to Amendment 1, the financial consideration from Bristol Myers Squibb was comprised of an upfront payment of $200.0 million, estimated research and development service fees, and contingent payments for development, regulatory and sales milestones for theeight targets. The Company was also entitled to tiered mid-single to low double-digit percentage royalties from potential future sales. Amendment 1 did not change the term of Bristol Myers Squibb’s royalty obligation under the BMS Agreement. Bristol Myers Squibb’s royalty obligation continues on a licensed-product by licensed-product basis until the later of (i) the expiration of the last claim of the licensed patents covering the licensed products in the country, (ii) the twelfth anniversary of the first commercial sale of a licensed product in a country, or (iii) the expiration of any applicable regulatory, pediatric, orphan drug or data exclusivity with respect to such product.

The Company elected the practical expedient related to contract modifications upon adoption of ASC 606 and combined the original agreement and Amendment 1. The Company determined that the identified promised goods and services which include the exclusive research, development and commercialization license, the related research services and expertise for the development of the product candidates should be combined with the participation in the joint research committee as one combined performance obligation for each collaboration target. The Company also concluded that, at the inception of the agreement, Bristol Myers Squibb’s options for the third and fourth targets were material rights and performance obligations. As such, the material rights were accounted for as part of the initial transaction price.

The Company received an upfront payment of $50.0 million from Bristol Myers Squibb in July 2014. In January and December 2016, Bristol Myers Squibb exercised the option to select the third and fourth targets, and paid the Company $10.0 million and $15.0 million, respectively, pursuant to the terms of the BMS Agreement. In December 2016, Bristol Myers Squibb selected a clinical candidate pursuant to the BMS Agreement, which triggered a $2.0 million pre-clinical milestone payment to the Company. In November 2017, the Company recognized a $10.0 million milestone payment from Bristol Myers Squibb upon approval of the investigational new drug application for the CTLA-4-directed PROBODY therapeutic.

The initial transaction price for the BMS Agreement and Amendment 1, collectively, was $304.7 million consisting of the upfront fees of $250.0 million, target selection fees for the third and fourth targets of $25.0 million, estimated research and development service fees of $17.7 million and milestone payments received up to January 1, 2018, of $12.0 million. The Company determined that the remaining potential milestone payments were probable of significant revenue reversal as their achievement was highly dependent on factors outside the Company’s control. Therefore, these payments were fully constrained and were not included in the transaction price upon the adoption of ASC 606 on January 1, 2018. The initial transaction pricefor the combined obligation for each collaboration target is recognized using an input measure. In applying the input method of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred for each combined performance obligation over the estimated research service period of each collaboration target.

During the first quarter of 2019, Bristol Myers Squibb terminated pre-clinical activities on three of the first four collaboration targets selected under the original 2014 BMS Agreement. The Company determined that upon the termination of pre-clinical activities on the three collaboration targets, it has no further obligations related to such targets. The Company accounted for the termination of the three targets as a modification and the related remaining unrecognized transaction price was reallocated to the remaining performance obligations. The Company continues to be obligated to perform research work under Amendment 1 executed in March 2017.

In February 2020, Bristol Myers Squibb dosed the first patient in the Part 2 cohort expansion portion of its ongoing BMS-986249 clinical study for the CTLA-4 program, which triggered a $10.0 million milestone payment to the Company pursuant to the terms of the BMS Agreement. The $10.0 million milestone payment was recognized as revenue in the first quarter of 2020 as the Company had completed its performance obligation related to this collaboration target.

In February 2021, the Company and Bristol Myers Squibb amended the BMS Agreement and entered into Amendment Number 2 to amend the Collaboration and License Agreement (“Amendment 2”), as previously amended by Amendment 1. Subsequent to Amendment 2, in addition to Bristol Myers Squibb’s ongoing development of the CTLA-4 program, Bristol Myers Squibb also had the exclusive worldwide rights to develop and commercialize PROBODY therapeutics for up to five oncology targets. Under the terms of Amendment 2, the period for target selection was extended and in 2022, all remaining targets were selected. The Company continues to collaborate with Bristol Myers Squibb to discover and conduct preclinical development of PROBODY therapeutics against targets selected by Bristol Myers Squibb over the estimated research period, which is projected to end in April 2025. Pursuant to Amendment 2, the Company was eligible to receive contingent payments for development, regulatory and sales milestones. It is also entitled to tiered mid-single to low double-digit percentage of royalties from potential future sales. The Company accounted for Amendment 2 as a modification and reallocated the remaining unrecognized transaction price to the remaining performance obligations.

In October 2022, the Company and Bristol Myers Squibb amended the BMS Agreement and entered into Amendment Number 3 (“Amendment 3”), as previously amended by Amendment 1 and Amendment 2, to clarify the rights and restrictions of certain new proprietary antibodies that the parties exchanged. There were no substantive changes to each party's performance obligations.

In March 2024, following a Bristol Myers Squibb corporate portfolio prioritization process, Bristol Myers Squibb notified CytomX that it does not intend to continue the development of BMS-986288 beyond the current Phase 2 study and terminated its collaboration license to the CTLA-4 target under the collaboration. BMS-986288 was Bristol Myers Squibb’s leading next generation PROBODY CTLA-4 program that it had previously prioritized over BMS-986249, which was a PROBODY version of ipilimumab.

In June 2024, Bristol Myers Squibb prioritized its pre-clinical research activities under the collaboration and revised the research scope by one collaboration target. The Company determined that it has no further obligations related to the target that was deprioritized and accounted for the reduction of the target as a modification and the related remaining unrecognized transaction price was reallocated to the remaining performance obligations. The Company has received in aggregate $297.0 million in upfront and milestone payments under the agreement. The Company's research efforts on all the ongoing programs were completed in April 2025 upon which the $11.6 million of remaining deferred revenue was fully recognized. In May 2025, one collaboration target was also terminated with two months written notice pursuant to the BMS Agreement and two preclinical programs remain in development with Bristol Myers Squibb responsible for further advancement.

ModernaTX, Inc.

The Company and ModernaTX, Inc. (“Moderna”) entered into a Collaboration and License Agreement (the “Moderna Agreement”) on December 30, 2022, the effective date, to collaborate on discovery and preclinical research and development activities to create investigational messenger RNA (“mRNA”) based conditionally activated therapies using the Company’s PROBODY therapeutic technology. Moderna is solely responsible for the development (preclinical and clinical), manufacturing, and commercialization of any products under the Moderna Agreement.

Under the terms of the Moderna Agreement, the Company granted Moderna an exclusive, worldwide right to develop and commercialize PROBODY therapeutics for the collaboration programs. In exchange, the Company received an upfront payment of $35.0 million in January 2023, including $5.0 million of prepaid research and development service fees. The Company will continue to receive research and development service fees according to the preclinical research work plans based on a prescribed FTE rate and is eligible to receive up to approximately$1.2 billion in future development, regulatory, and commercial milestone payments. The Company is also eligible to receive tiered royalties from high-single digit to low-teen percentage rates of annual global net sales of any products that are commercialized under the Moderna Agreement.

The Company determined that each collaboration program was a distinct performance obligation consisting of the exclusive research, development and commercialization license, research services, and participation in the joint steering committee. The initial transaction price is $51.7 million, consisting of the upfront fee of $30.0 million and estimated research funding of $21.7 million from Moderna. The initial transaction price excludes milestone payments as the achievement of such milestones is dependent on factors outside of the Company’s control and recognition would be probable of significant revenue reversal. As such, the milestones are fully constrained at the inception of the contract. The Company will re-evaluate the transaction price at each reporting date or as uncertain events are resolved or other changes in circumstances occur.

The transaction price at the contract inception was allocated among the performance obligations using the SSP of each performance obligation, which was determined to be equal due to the early stage of the collaboration programs. The transaction price allocated to the collaboration programs is recognized using an input method. In applying the input measure of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred for the respective collaboration program over an estimated service period offour years. Due to Moderna's budget considerations in 2025, the Company's remaining activities for its performance obligation are currently paused pending future alignment with Moderna.

As of December 31, 2025 and 2024, deferred revenue relating to the Moderna Agreement was$9.3 million and$9.3 million, respectively. The amount due from Moderna under the Moderna Agreement was$0 and $0.9 million as of December 31, 2025 and December 31, 2024, respectively.

Regeneron Pharmaceuticals, Inc.

The Company and Regeneron Pharmaceuticals Inc. (“Regeneron”) entered into a Collaboration and License Agreement (the “Regeneron Agreement”) on November 16, 2022, to collaborate on creation of conditionally-activated investigational bispecific cancer therapies utilizing the Company’s PROBODY® therapeutic platform and Regeneron’s Veloci-Bi® bispecific antibody development platform. The Company and Regeneron will collaborate on preclinical research and discovery activities for initially agreed upon collaboration programs (“Collaboration Program”) with an option to expand additional Collaboration Programs (“Additional Collaboration Program Option”).

Under the Collaboration and License Agreement, the Company granted Regeneron an exclusive, worldwide, royalty-bearing license under certain Company intellectual property to develop, manufacture, commercialize and otherwise exploit licensed products (“Licensed Products”) for all human and non-human diagnostic, prophylactic and therapeutic uses in oncology. Regeneron is responsible for funding the cost of preclinical research and discovery activities of both parties for all Licensed Products and for funding the cost of development, manufacturing and commercialization of all Licensed Products worldwide.

Pursuant to the Regeneron Agreement, the consideration from Regeneron is comprised of an upfront fee of $30.0 million, contingent payments for development and regulatory milestones and commercial milestone payments of up to an aggregate of approximately $0.8 billion. If Regeneron exercises its Additional Collaboration Program Option, the Company would be eligible to receive additional upfront and milestone payments aggregating up to approximately $1.2 billion. The Company is also entitled to tiered royalties from high-single digit to low-teen percentage royalties from potential future sales. In addition, the Company will receive research and development service fees based on a prescribed FTE rate.

The Company determined that each collaboration program was a distinct performance obligation consisting of an exclusive research, development and commercialization license, research and development services and participation in the joint research committee. The Company concluded that at the inception of the agreement, Regeneron’s Additional Collaboration Program Option did not include material rights and therefore was not a performance obligation. As such, each option will be accounted for as a separate arrangement upon exercise. The initial transaction price is $39.2 million consisting of the upfront fee of $30.0 million and estimated research and development service fees of $9.2 million. The initial transaction price excludes milestone payments as the achievement of such milestones is dependent on factors outsideof the Company’s control and recognition would be probable of significant revenue reversal. As such, the milestones are fully constrained at the inception of the contract. The Company will re-evaluate the transaction price at each reporting date or as uncertain events are resolved or other changes in circumstances occur.

The transaction price was allocated among the performance obligations using the SSP of each performance obligation, which was determined to be equal at the inception of the agreement. The transaction price allocated to each performance obligation is recognized using an input measure. In applying the input measure of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred for each combined performance obligation over the estimated research service period offour years, which is projected to end in November 2026.

As of December 31, 2025 and 2024, deferred revenue relating to the Regeneron Agreement was$10.5 million and$15.6 million, respectively. The amount due from Regeneron under the Regeneron Agreement was $0.8 million and $1.0 million as of December 31, 2025 and December 31, 2024, respectively.

Contract Liabilities

The following table presents changes in the Company’s total contract liabilities for the years ended in December 31, 2025 and 2024 (in thousands):

The Company expects that the$28.5 million of deferred revenue related to the following contracts as of December 31, 2025 will be recognized as revenue based on actual FTE effort and estimated program progress as set forth below. However, the timing of revenue recognition could differ from the estimates depending on facts and circumstances impacting the various contracts, including progress of research and development, resources assigned to the contracts by the Company or its collaboration partners or other factors outside of the Company’s control.

•

The$8.6 million of deferred revenue related to the Astellas Agreement is expected to be recognized until 2026.

•

The$9.3 million of deferred revenue related to the Moderna Agreement, together with research and development service fees, are expected to be recognized pending alignment with Moderna's budget consideration.

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The$10.5 million of deferred revenue related to the Regeneron Agreement, together with research and development service fees, is expected to be recognized until 2026.

9. License Agreement

UCSB Agreement

In August 2010, the Company entered into an exclusive, worldwide license agreement with University of California, Santa Barbara (“UCSB”), relating to the use of certain patents and technology, and to patent rights the Company co-owns with UCSB that cover certain conditionally activatable antibodies (the “UCSB Agreement”). Pursuant to the UCSB Agreement, the Company has annual minimum royalty obligations of $0.2 million under the terms of certain exclusive licensed patent rights. In April 2019, the Company entered into Amendment No.3 to the UCSB Agreement to adjust and clarify certain sublicense terms (“Amendment No.3”). Under the terms of Amendment No.3, the Company agreed to make an additional annual license maintenance fees of $0.8 million through 2031. In the event that the Company terminates the agreement due to material concern of the safety or efficacy of the related technology,50% of all remaining maintenance fees will become due immediately. Otherwise, all remaining maintenance fees will become due immediately upon early termination of the agreement unless there is a material breach by UCSB.

In 2023, the Company incurred $0.2 million of sublicense fees triggered by achieving the clinical candidate milestone under the Astellas Agreement. In 2024, the Company incurred $0.6 million of sublicense fees triggered by achieving the GLP toxicology studies milestone for the first clinical candidate which was nominated by Astellas in 2023, as well as by achieving the clinical candidate nomination milestone for a second collaboration target under the Astellas Agreement. In the first quarter of 2025, the Company incurred $0.2 million of sublicense fees triggered by achieving the GLP toxicology studies milestone for the second clinical candidate which was nominated by Astellas in March 2024.

During the years ended December 31, 2025 and 2024, the Company incurred sublicense expenses of $1.1 million and $1.6 million, respectively, under the provisions of the UCSB Agreement.

ImmunoGen (acquired by AbbVie in 2024)

In December 2019, the Company entered into a License Agreement (the “ImmunoGen 2019 License”) with ImmunoGen, Inc. to obtain an exclusive license with respect to epithelial cell adhesion molecule (“EPCAM”). Under the ImmunoGen 2019 License, ImmunoGen agreed to transfer its know-how, patents, intellectual property rights, and technology transfer materials and information related to its EpCAM program. The license gives the Company the sole ability to develop, manufacture, use and commercialize any licensed product that incorporates, is comprised of, or otherwise derived from PROBODY technology that targets EpCAM in any human therapeutic field on a worldwide basis. In exchange, the Company made an upfront license payment of $7.5 million, and will pay up to $35.0 million in certain clinical development milestones and up to $320.0 million in regulatory approval and commercial milestone payments, if achieved. ImmunoGen is also entitled to royalties on product sales ranging from the mid-to-high single digits percentages.

In April 2024, the Company made a $5.0 million payment of the $35.0 million in potential clinical development milestone payments to AbbVie (formerly ImmunoGen) with respect to achieving the milestone of dosing the first patient for Varseta-M under the ImmunoGen 2019 License Agreement.

Varseta-M, which is currently in Phase 1 development, is covered under the ImmunoGen License Agreement.

Seattle Genetics, Inc ("SGEN")

In August 22, 2023, the Company entered into a Transition Agreement (the “Transition Agreement”) with AbbVie Global Enterprises Ltd. (“AbbVie”), pursuant to which the Company regained exclusive worldwide rights to develop CX-2029, a CD71-targeting conditionally activated antibody drug conjugate. The Transition Agreement superseded the CD71 Co-Development and License Agreement (the “Collaboration Agreement”) entered into between the Company and AbbVie Ireland Unlimited Company (an affiliate entity of AbbVie) in 2016, that was terminated in May 2023, and granted certain intellectual property rights from AbbVie to enable the continued development of CX-2029 by the Company for all human and nonhuman diagnostic, prophylactic, and therapeutic uses. Pursuant to the Transition Agreement, the Company paid an annual license maintenance fee of $0.3 million to SGEN for certain related technology starting 2023 through the date on which licensee receives first regulatory approval in the territory for the applicable licensed product. The Company terminated the Transition Agreement in the first quarter of 2025.

10. Commitments and Contingencies

The Company is subject to claims and assessments from time to time in the ordinary course of business, but is not aware of any such matters, individually or in the aggregate, that will have a material adverse effect on the Company’s financial position, results of operations or cash flows.

Indemnifications

In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company has also 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.

11. Leases

Operating Lease

In December 2015, the Company entered into a lease (the “2016 Lease”) of office and laboratory space located in South San Francisco, California for the Company’s corporate headquarters. The 2016 Lease has an initial term often years through 2026 and the Company has an option to extend the initial term for an additional five years at the then fair rental value as determined pursuant to the 2016 Lease.

In addition, the Company obtained a standby letter of credit (the “Letter of Credit”) in an amount of approximately $0.9 million, which may be drawn by the Landlord to be applied for certain purposes upon the Company’s breach of any provisions under the 2016 Lease. The Company recorded $0.9 million of cash securing the Letter of Credit as non-current restricted cash on its balance sheet as of December 31, 2025 and 2024.

Supplemental information related to leases are as follows:

In March 2023, the Company entered into a sublease agreement for a portion of its existing office and laboratory space. The sublease is classified as an operating lease whereby sublease income, which is included as an offset against operating lease cost, is recognized on a straight-line basis over the sublease term that expires on September 30, 2026. In January 2026, the Company and the sublease tenant entered into a sublease termination agreement, resulting in an early termination of the sublease in February 2026. Pursuant to the sublease termination agreement, the sublessee will pay an aggregate of $0.6 million as final settlement of the sublease. The $0.6 million was collected in January 2026.

In November 2025, the Company entered into a lease (the “2026 Lease”) of office and laboratory space located in Emeryville, California for the Company’s corporate headquarters. The contractual commencement date forthe 2026 Lease will be October 1, 2026. The 2026 Lease will expire on December 31, 2029, and the Company has two options to extend the term, each for an additionaltwo years, at the then fair market rent as determined under the term of the 2026 Lease. The Company is not reasonably certain to exercise the options. Under the terms of the lease, the Company is obligated to make aggregate future minimum lease payments totaling approximately $5.7 million over the lease term payable starting from January 2027, exclusive of operating expenses and other common area charges. The Company determined that the lease commencement date for accounting purpose is April 1, 2026, when the office and laboratory space is expected to be available for use by the Company to begin construction of its leasehold improvements.

12. Common Stock

In February 2020, the Company entered into the Open Market Sale Agreement (as amended on each of March 4, 2022 and August 9, 2024, the “Sales Agreement”) with Jefferies LLC (“Jefferies”), as sales agent, providing for the sale of up to $75,000,000 of its common stock, at par value $0.00001 per share, from time to time under an at-the-market (“ATM”) offering. Pursuant to the Sales Agreement, Jefferies as the sales agent will receive a commission of 3.0% of the gross sales price for shares of common stock sold under the Sales Agreement. In 2024, under the ATM program, the Company sold approximately 3.9 million shares at a weighted average price of $1.82 per share for net proceeds of approximately $6.9 million after deducting sales commissions and related issuance cost. In the fourth quarter of 2025, the Company sold approximately 4.9 million shares at a weighted average price of $3.44 per share under the ATM program for net proceeds of approximately $16.3 million, after deducting sales commissions and related issuance cost.

In May 2025, the Company completed an underwritten public offering of 76,923,076 shares of common stock at a price of $1.30 per share. The aggregate net proceeds received by the Company from the offering were approximately $93.4 million, after deducting underwriting discounts and commissions of $6.0 million and offering expenses of $0.6 million. Longitude Venture Partners V, L.P. (“LVPV”) acquired approximately 11.5 million shares of common stock through the underwritten public offering. Longitude Capital Partners V, LLC (“LCPV”) is a general partner of LVPV. A member of the Company’s board of directors serves as a managing director of LCPV, and therefore, LCPV is considered a related party of the Company. The Company had no other significant related party transactions with LCPV.

In June 2023, the Company entered into an agreement with BVF Partners L.P. (“BVF”) for a private placement (the “Private Placement Agreement”) and received an aggregate net proceeds of approximately $29.7 millionin July 2023, after deducting issuance costsof approximately $0.3 million. In the private placement, the Company issued pre-funded warrants to BVF to purchase up to 14,423,077 shares of common stock, accompanying Tranche 1 warrants to purchase up to 5,769,231 shares of common stock and accompanying Tranche 2 warrants to purchase up to 5,769,231 shares of common stock, at a combined price of $2.08 per share. The initial exercise price of the Tranche 1 and Tranche 2 warrants was $4.16 per share and $6.24 per share, respectively. The public offering in May 2025 triggered an adjustment provision in the Tranche 1 and Tranche 2 warrants, pursuant to which the exercise prices were reduced to $2.73 and $3.77 per share, respectively. As a result of the exercise price reduction adjustment, the Company recorded deemed dividend of $3.0 million as a down round adjustment for the warrants in additional paid-in-capital against retained earnings in 2025. The deemed dividend is treated as a reduction to income available to common stockholders for the basic net income (loss) per share calculation. However, the adjustment to net income (loss) is not required in periods when the warrants are out-of-the-money for the diluted net income (loss) per share calculation. The Tranche 1 warrants expired without being exercised in July 2025 and the Tranche 2 warrants will expire in July 2026. In May 2024, BVF exercised its right to purchase 7.5 million shares of common stock through its pre-funded warrants at an exercise price of $0.00001 per share. In May 2025, BVF exercised its right to purchase the remaining 6.9 million shares of common stock through its pre-funded warrants at an exercise price of $0.00001 per share.

The following table summarizes the Company's activities of outstanding warrants for the year ended December 31, 2024 and 2025:

In the May 2024 annual meeting of stockholders, the Company's authorized shares of common stock were approved to increase from 150,000,000 shares to 300,000,000 shares.

13. Stock-based Compensation

The 2010 Plan and 2011 Plan

In 2010, the Company adopted its 2010 Stock Incentive Plan (the “2010 Plan”) which provided for the granting of stock options to employees, directors and consultants of the Company. Options granted under the 2010 Plan were either incentive stock options (“ISOs”) or nonqualified stock options (“NSOs”).

In February 2012, the Company adopted its 2011 Stock Incentive Plan (the “2011 Plan”). The 2011 Plan is divided into two separate equity programs, an option and stock appreciation rights grant program and a stock award program. In conjunction with adopting the 2011 Plan, the Company discontinued the 2010 Plan and released the shares reserved and still available under that plan.

In connection with the consummation of the IPO in October 2015, the board of directors adopted the Company’s 2015 Equity Incentive Plan (the “2015 Plan” and collectively with the 2010 Plan and 2011 Plan, the “Plans”). In conjunction with adopting the 2015 Plan, the Company discontinued the 2011 Plan with respect to new equity awards.

The 2015 Plan

The 2015 Plan authorized the board of directors to grant incentive stock options, non-statutory stock options and RSUs to employees, directors, non-employee directors and consultants of the Company. Stock options under the 2015 Plan may be granted for periods of up toten years. All stock options issued to date have had a 10-year life. Under the terms of the 2015 Plan, stock options may be granted at an exercise price not less than the estimated fair value of the Company’s common stock on the date of grant, as determined by the Company’s board of directors. For employees holding more than 10% of the voting rights of all classes of stock, the exercise price of ISOs and NSOs may not be less than 110% of the estimated fair value of the shares on the date of grant, as determined by the board of directors. To date, stock options granted under the 2015 Plan generally vest over four years and vest at a rate of 25% upon the first anniversary of the issuance date and 1/48 th per month thereafter.

In June 2025, the Company’s stockholders approved the amendment and restatement of the 2015 Plan, among other things, to increase the aggregate number of shares of the Company’s common shares available for grant to approximately 6.3 million shares, remove the“evergreen provision” which provided an annual increase of shares under the Plan on January 1 of each calendar year by 4% of the total number of issued and outstanding shares of common stock as of January 1 of the same year. As of December 31, 2025 and 2024,5,191,986 shares and 2,319,648 shares of common stock, respectively, were available for future issuance under the 2015 Plan.

The 2019 Plan

In September 2019, the Board of Directors adopted the 2019 Employment Inducement Incentive Plan (the “2019 Plan”) which provides for the grant of stock options and other equity awards to any employee who has not previously been an employee or director of the Company or who is commencing employment with the Company following a bona fide period of nonemployment by the Company. Awards granted under the 2019 Plan are intended to constitute “employment inducement awards” under Nasdaq Listing Rule 5635(c)(4). Options granted under the 2019 Plan are nonqualified stock options (“NSOs”) which may be exercisable for periods of up toten years and the options shall be granted at an exercise price of not less than 100% of the fair market value of the Company’s common stock on the date of grant.

The initial number of shares of common stock available for future issuance under the 2019 Plan was 1,815,000. During 2021, the total number of shares of common stock available for issuance under the 2019 Plan has increased by 1,000,000 shares. In conjunction with the amendment of the 2015 Plan approved by the Company's stockholders in June 2025, the Company discontinued the 2019 Plan with respect to new equity awards. All the remaining shares available for grant under the 2019 Plan were released and transferred to the 2015 Plan. As of December 31, 2025 and 2024, no shares and 1,658,672 shares, respectively, of common stock were available for future issuance under the 2019 Plan.

The following table summarizes the Company's stock option activities:

The aggregate intrinsic values of options exercised, outstanding and exercisable were calculated as the difference between the exercise price of the options and the quoted market price of the underlying common stock as of December 31, 2025.

The Company recorded $3.9 million and $5.8 million of stock-based compensation expense related to the stock option plans for the years ended December 31, 2025 and 2024, respectively.

The options granted in the years ended December 31, 2025 and 2024 had weighted-average per share grant-date fair values of $1.41 and $1.21, respectively. As of December 31, 2025, the unrecognized compensation expense with respect to options granted was$7.3 million and is expected to be recognized over 2.58 years.

Time-based RSUs (“TRSU”)

The following table summarizes the Company's TRSU activities:

The Company recorded $1.5 million and $1.5 million of stock-based compensation expense related to the TRSUs for the year ended December 31, 2025 and 2024, respectively. As of December 31, 2025, the unrecognized compensation expense with respect to the TRSUs was $2.1 million which is expected to be recognized over 1.5 years. The TRSUs generally vest ratably over two to four years.

Performance-based RSUs ("PSU")

2023 PSU

In February 2023, the Company granted 760,000 PSUs to executive employees with an aggregated grant date fair value of approximately $1.9 million. Vesting for 50% of the PSUs granted occurred upon attaining certain specific milestones by December 2024 (“2023-Tranche-1”), and the remaining 50% were set to vest upon attaining certain specific milestones by December 2025 (“2023-Tranche-2”). As of December 31, 2024, the PSUs for 2023-Tranche-1 were canceled as the related performance condition was not met by December 2024. The performance condition for 2023-Tranche-2 was determined to be satisfied in June 2025 and the 2023-Tranche-2 PSUs were fully vested. As a result, the Company recorded $0.7 million compensation cost for the year ended December 31, 2025.

2024 PSU

In January 2024, the Company granted 810,000 PSUs to executive employees with an aggregated grant date fair value of approximately $1.3 million. Vesting for 50% of the PSUs granted will occur upon attaining certain specific milestones by December 2025 (“2024-Tranche-1”), and the remaining 50% will vest upon attaining certain specific milestones by December 2026 (“2024-Tranche-2”). As of December 31, 2025, the PSUs for 2024-Tranche-1 were canceled as the related performance condition was not met by December 2025. The Company determined that it is not probable that the performance conditions will be satisfied for 2024-Tranche-2 and henceno compensation cost was recorded for these awards through December 31, 2025.

2025 PSU

In September 2025, the Company granted 413,350 PSUs to executive employees with an aggregated grant date fair value of approximately $1.2 million. Vesting for one third of the PSUs granted will occur upon attaining a certain specific milestone (“2025-Tranche-1”), vesting for one third of the PSUs granted will occur upon attaining a certain specific milestone (“2025-Tranche-2”) on June 30, 2027 or later, and the remaining one third will vest upon attaining a certain specific milestone on June 30, 2028 or later (“2025-Tranche-3”). The Company determined that it is not probable that the performance conditions will be satisfied for each of these tranches and henceno compensation cost was recorded for these awards through December 31, 2025.

The following table summarizes the Company's PSU activities:

As of December 31, 2025, unrecognized compensation expense with respect to PSUs granted was $1.9 million, of which $1.5 million is expected to be recognized over approximately 1.6 years and $0.4 million will be recognized upon occurrence of the specific milestone.

Employee Stock Purchase Plan

Concurrent with the completion of the IPO in October 2015, the Company’s Employee Stock Purchase Plan (“ESPP”) became effective. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP generally provides for six-month offering periods, and at the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. The Company issued 207,528 and 383,346 shares of common stock under the ESPP in 2025 and 2024, respectively. In June 2025, the Board of Directors approved an amendment and restatement of the ESPP to remove the expiration date of the plan and the annual increase of shares on January 1 of each calendar year as defined under the ESPP.

Shares available for future purchase under the ESPP were 348,824 shares and 556,352 shares at December 31, 2025 and 2024, respectively. The compensation expense related to the ESPP was $0.2 million and $0.3 million for the years ended December 31, 2025 and 2024, respectively. As of December 31, 2025, there was $0.1 million of unrecognized compensation cost related to the ESPP, which the Company expects to recognize over 5 months.

Stock Based Compensation

Total stock-based compensation recorded related to stock options, TRSUs, PSUs and the ESPP was as follows (in thousands):

Fair Value Assumptions:

The Company estimated the fair value of employee stock options and ESPP using the Black-Scholes valuation model based on the date of grant with the following weighted average assumptions:

14. Income Taxes

The Company derives its income only from the United States. The components of the provision for income taxes are as follows (in thousands):

The table reflects the ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09). See “Note 2. Basis of Presentation and Summary of Significant Accounting Policies — Recent Accounting Pronouncements” for additional information on the adoption of ASU 2023-09.

A reconciliation of the Company’s effective tax rate to the statutory U.S. federal rate is as follows:

The types of temporary differences that give rise to significant portions of the Company’s deferred income tax assets and liabilities are set out below (in thousands):

The Company has established a valuation allowance against all of its net deferred tax assets. Management considered all available evidence, both positive and negative, including but not limited to our historical operating results, income or loss in recent periods, cumulative losses in recent years, forecasted earnings, future taxable income, and significant risk and uncertainty related to forecasts, and concluded the deferred tax assets are not more likely than not to be realized. The net change in the total valuation allowance for the years ended December 31, 2025 and 2024 was an increase of $25.2 million and a decreaseof $13.4 million, respectively.

The Company had net operating loss carryforwards for federal and state income tax purposes of approxi mately $394.5 million and $56.9 million, respectively, as of December 31, 2025, available to reduce future taxable income. Of the federal net operating loss carryforwards, $65.6 million will begin to expire in 2034, if not utilized and $328.9 million will be carried forward indefinitely. The state net operating loss carryforwards will begin to expirein 2032, if not utilized.

The Company also has federal and state research and development tax credit carryforwards of $26.4 million and $15.0 million, respectively, as of December 31, 2025 available to reduce future income taxes. The federal research and development tax credits will begin to expirein 2031 if not utilized. The state research and development tax credits will carryforward indefinitely.

Internal Revenue Code section 382 (“IRC Section 382”) places a limitation (the “Section 382 Limitation”) on the amount of taxable income that can be offset by net operating loss (“NOL”) carryforwards after a change in control (generally greater than 50% change in ownership) of a loss corporation. California has similar rules. When such ownership change occurs, IRC Section 382 limits the use of NOLs and credits in subsequent periods based on the annual Section 382 Limitation. The Company performed an IRC Section 382 analysis and determined that there was no ownership change in 2025 which may result in a reduction of its NOLs or its research and development credits expiring unused.

A reconciliation of the beginning and ending unrecognized tax benefit amount is as follows (in thousands):

Of the unrecognized tax benefits as of each of December 31, 2025 and 2024, approximately$2.3 million would affect the Company’s effective tax rate if recognized. Penalties and interest of $1.0 million and $1.0 million, respectively, have been accrued for as of December 31, 2025.

The Company files income taxes in the U.S. federal jurisdiction, the state of California and various other U.S. states. The state of California contested the Company’s tax position on revenue apportionment for upfront and milestone payments resulting from the Company’s collaboration and licensing agreements for the years 2017 and 2018. In September 2023, the Company received Notice of Proposed Assessment (“NOPA”) from the Franchise Tax Board. The Company recorded an uncertain tax position of $4.4 million in long term liabilities for the proposed tax assessment, penalties and interest through December 31, 2025. Additional utilization of carryforward attributes and indirect federal tax effects of the assessment would result in a reduction in deferred tax assets of $5.0 million. The Company filed a protest to contest the proposed assessment in November 2023. Due to the ongoing nature of the

examination and discussions with the state of California, the Company is unable to estimate a date by which this matter will be resolved.

15. Defined Contribution Plan

The Company sponsors a defined contribution plan under Section 401(k) of the Internal Revenue Code covering substantially all full-time U.S. employees. Employee contributions are voluntary and are determined on an individual basis subject to the maximum allowable under federal tax regulations. During the years ended December 31, 2025 and 2024, the Company made contributions to the plan of $0.5 million and $0.6 million, respectively.

16. Segment

The Company operates as asingle operating segment. The Chief Executive Officer is identified as the Chief Operating Decision Maker (“CODM”). The CODM primarily reviews the Company’s financial information on an aggregate basis. The CODM utilizes the aggregated financial information to make strategic decisions, assess performance, and allocate resources across the Company. The aggregate information includes the revenue by collaboration partner, research and development expense by program, as well as net income that is reported on the Statements of Operations and Comprehensive Income (Loss). Net income (loss) is used to monitor budget versus actual results in assessing performance of the segment and in establishing management's compensation. The measure of segment assets is reported on the Balance Sheets as total assets. All of the Company’s long-lived assets are located in the United States. In addition to the revenue by collaborative partners disclosed in Note 8, the CODM reviews the following significant expenses in making decisions about the allocation of resources and assessing performance (in thousands):

17. Restructuring

On January 6, 2025, the Company announced a restructuring plan to streamline its organization and prioritize Varseta-M (EpCAM PROBODY®ADC), CX-801 and its activities to support its research collaborations. This plan resulted in a reduction of approximately 40% of its workforce and was substantially completed in the first quarter of 2025. The Company incurred total restructuring charges of $2.8 million, primarily related to one-time severance payments and other employee-related costs. This includes $1.7 million ofresearch and development expenses and $1.1 million of general and administrative expenses that were recorded during the twelve months ended December 31, 2025.

The following is a summary of accrued restructuring costs as of December 31, 2025 (in thousands):

18. Subsequent Event

In March 2026, Astellas chose to not advance the remaining preclinical programs under the alliance, resulting in a termination of the collaboration effective in the second quarter of 2026. CytomX is currently assessing options to advance select targets previously covered under the Astellas collaboration as part of its ongoing research and development strategy.