C4 Therapeutics, Inc.

C4 THERAPEUTICS, INC.

Notes to Condensed Consolidated Financial Statements

Note 1. Nature of the business and basis of presentation

C4 Therapeutics, Inc., or, together with its subsidiary, the Company, is a clinical-stage biopharmaceutical company dedicated to delivering on the promise of targeted protein degradation, or TPD, science to create a new generation of small-molecule medicines that transform patients’ lives. Leveraging our proprietary TORPEDO platform, the Company efficiently designs and optimizes small molecule protein degraders that are highly active against their desired targets by harnessing the body’s natural process for destroying unwanted proteins. Our strategy is to develop degraders that modulate clinically validated disease pathways with best-in-class or first-in-class potential to address significant unmet patient needs. To date, our degraders have demonstrated oral bioavailability and catalytic activity, and we have also leveraged our capability to design compounds that are brain penetrant.

Our clinical pipeline is comprised of two oncology programs while our discovery efforts are focused on inflammation, neuroinflammation, and neurodegeneration. Additionally, our partnership strategy allows us to further expand our reach in both oncology and non-oncology indications.

The Company was incorporated in Delaware on October 7, 2015 and has its principal office in Watertown, Massachusetts.

Liquidity and capital resources

Since its inception, the Company’s primary activities have been focused on research and development activities, building the Company’s intellectual property, recruiting and retaining personnel, and raising capital to support these activities. To date, the Company has funded its operations primarily with proceeds received from the sales of redeemable convertible preferred stock, public offerings of the Company’s common stock, private placement of the Company's common stock, through its collaboration agreements, and debt financing.

The Company has incurred recurring losses since its inception, including net losses of $25.1 million and $26.3 million for the three months ended March 31, 2026 and 2025, respectively. In addition, as of March 31, 2026, the Company had an accumulated deficit of $763.8 million. To date, the Company has not generated any revenue from product sales as none of its product candidates have been approved for commercialization. The Company expects to continue to generate operating losses for the foreseeable future.

The Company expects that its cash, cash equivalents, and marketable securities of $268.3 million as of March 31, 2026 will be sufficient to fund its operations for at least the next twelve months from the date of issuance of these condensed consolidated financial statements. Accordingly, the condensed consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.

Risks and uncertainties

The Company is subject to risks common to other life science companies in the early development stage including, but not limited to, uncertainty of ability to raise additional financing, product development and commercialization, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, lack of marketing and sales history, product liability, protection of proprietary technology and intellectual property, and compliance with regulations of the Food and Drug Administration, or the FDA, and other government agencies. If the Company does not successfully advance its programs into and through human clinical trials and commercialize any of its product candidates either directly or through collaborations with other companies, the Company may be unable to produce product revenue or achieve profitability. There can be no assurance that the Company’s research and development efforts will be successful, adequate protection for the Company’s intellectual property will be obtained, any products developed will obtain necessary government regulatory approval, or any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies.

Note 2. Summary of significant accounting policies

Basis of presentation and consolidation

The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America, or U.S. GAAP, and applicable rules and regulations of the Securities and Exchange Commission, or the SEC, regarding interim financial reporting, and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. These condensed consolidated financial statements include the accounts of C4 Therapeutics, Inc. and its subsidiary, C4T Securities Corporation. All intercompany balances and transactions have been eliminated in consolidation.

Unaudited interim financial information

The accompanying condensed consolidated balance sheet as of March 31, 2026, the condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2026 and 2025, the condensed consolidated statements of stockholders’ equity for the three months ended March 31, 2026 and 2025, and the condensed consolidated statements of cash flows for the three months ended March 31, 2026 and 2025, and the related interim disclosures are unaudited. These unaudited condensed consolidated financial statements include all adjustments necessary, consisting of only normal recurring adjustments, to fairly state the financial position and the results of the Company’s operations and cash flows for interim periods in accordance with U.S. GAAP. Interim period results are not necessarily indicative of results of operations or cash flows for a full year or any subsequent interim period. The accompanying condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements as of and for the year ended December 31, 2025, and notes thereto, which are included in the Company’s 2025 Annual Report on Form 10-K that was filed with the SEC on February 26, 2026, or the 2025 Annual Report.

Use of estimates

The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. This process may result in actual results differing materially from those estimated amounts used in the preparation of the condensed consolidated financial statements if these results differ from historical experience or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, amounts and timing of revenues recognized under the Company’s research and development collaboration arrangements, prepaid and accrued research and development expense, incremental borrowing rate used in the measurement of lease liabilities, and estimated volatility used in fair valuation of stock options. The Company assesses estimates on an ongoing basis; however, actual results could materially differ from those estimates.

Significant accounting policies

The Company’s significant accounting policies are disclosed in the audited condensed consolidated financial statements for the year ended December 31, 2025, which are included in the Company’s 2025 Annual Report. Since the date of those condensed consolidated financial statements, there have been no material changes to the Company’s significant accounting policies.

Recently issued accounting standards

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, or ASU 2024-03. ASU 2024-03 requires enhanced disclosures of disaggregated income statement expenses. Disclosure within the notes of the financial statements for each annual and interim period should include: employee compensation, depreciation, and intangible asset amortization, included in each relevant expense caption; certain amounts that are already required to be disclosed under current GAAP in the same disclosure as the other disaggregation requirement; a qualitative description of the amounts remaining in relevant expense captions that are not separately disaggregated quantitatively; and the total amount of selling expenses and, in annual reporting periods, an entity’s definition of selling expenses. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning December 15, 2027. Early adoption is permitted. The Company is currently evaluating the effect that adoption of ASU 2024-03 will have on its consolidated financial statements.

Note 3. Fair value measurements

The following table presents information about the Company’s financial assets measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values as of March 31, 2026 (in thousands):

There have been no transfers between fair value levels during the three months ended March 31, 2026.

The following table sets forth the fair value of the Company’s financial assets by level within the fair value hierarchy at December 31, 2025 (in thousands):

The Company classifies its money market funds, which are valued based on quoted market prices in active markets, with no valuation adjustment, as Level 1 assets within the fair value hierarchy.

Marketable securities consist of U.S. Treasury securities, U.S. government debt securities, and corporate debt securities, all of which are classified as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities. Marketable securities are classified within Level 2 of the fair value hierarchy because pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reporting date, and fair value is determined using models or other valuation methodologies on a recurring basis.

Note 4. Marketable securities

Marketable securities as of March 31, 2026 consisted of the following (in thousands):

Marketable securities as of December 31, 2025 consisted of the following (in thousands):

Marketable securities classified as current have maturities of less than one year and are classified as available-for-sale. Marketable securities classified as non-current are those that: (i) have a maturity of greater than one year, and (ii) are not intended to be liquidated within the next twelve months, although these funds are available for use and, therefore, are classified as available-for-sale. No available-for-sale debt securities held as of March 31, 2026 or December 31, 2025 had remaining maturities greater than five years.

Based on factors such as historical experience, market data, issuer-specific factors, and current economic conditions, the Company didnot record an allowance for credit losses at March 31, 2026 and December 31, 2025, related to these securities.

Note 5. Property and equipment

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

Depreciation expense related to property and equipment is as follows (in thousands):

Note 6. Leases

The Company leases office and laboratory space under a non-cancelable operating lease. In addition, the Company subleases a portion of its office and laboratory space. In September 2025, the Company entered into a sublease agreement with a third party, or the 2025 Sublease, for a portion of the office and laboratory space in Suite 200 at 490 Arsenal Way, Watertown, Massachusetts. The term of the 2025 Sublease ends in January 2029, with an option to extend for an additionaltwo year term. The Company began recognizing sublease income upon the commencement of the 2025 Sublease in February 2026.

There have been no material changes to the terms of the Company’s lease during the three months ended March 31, 2026. For additional information, please read Note 6, Leases, to the audited consolidated financial statements included in the Annual Report.

Note 7. Accrued expenses and other current liabilities

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

Note 8. Collaboration and license agreements

Pfizer Collaboration and Supply Agreement

On September 30, 2025, the Company entered into a Clinical Trial Collaboration and Supply Agreement with Pfizer, or the Pfizer Agreement. Pursuant to the Pfizer Agreement, Pfizer will supply the Company with elranatamab (ELREXFIO®), a B-cell maturation antigen CD3 targeted bispecific antibody, for the Company's ongoing Phase 1b trial evaluating the safety and tolerability of cemsidomide, an IKZF1/3 degrader, and dexamethasone in combination with elranatamab as a second-line or later therapy for patients with multiple myeloma. Under the terms of the Pfizer Agreement, Pfizer will supply elranatamab for use in the trial at no cost to the Company, while the Company will sponsor, conduct and pay the costs of the trial. The Pfizer Agreement provides that the Company and Pfizer will jointly own clinical data generated from the trial. The collaboration is managed by a joint development committee responsible for coordinating all regulatory and other activities under the Pfizer Agreement. Under the terms of the Pfizer Agreement, each party has various termination rights under certain circumstances, including material breach, insolvency, and other customary provisions, subject to certain conditions.

MKDG Collaboration and License Agreement

On March 1, 2024, the Company entered into a license and collaboration agreement with MKDG, or the MKDG Agreement, to discovertwo targeted protein degraders against critical oncogenic proteins.

Under the terms of the MKDG Agreement, the Company granted MKDG a worldwide, exclusive license under certain of the Company's intellectual property rights to develop, manufacture, and commercializetwo targeted protein degraders against critical oncogenic proteins within the KRAS family. MKDG is responsible for all development, regulatory approval, manufacturing and commercialization costs. Under the terms of the MKDG Agreement, MKDG agreed to make an upfront cash payment of $16.0 million and to fund the Company's discovery research efforts. The Company is eligible to receive approximately $740 million in the aggregate in discovery, regulatory, and commercial milestone payments across the collaboration, plus tiered royalties on net sales. Royalties payable from MKDG to the Company range from mid-single digit to low-double digit percentages, subject to reductions under certain circumstances as described in the MKDG Agreement. In April 2025, the Company earned a $1.0 million milestone for the achievement of a discovery milestone for one of the active collaboration targets, which resulted in the addition of $1.0 million to the transaction price for the collaboration. As the research activities with MKDG have progressed and evolved over time, there is onlyone target on which the parties continue to collaborate on.

The collaboration is managed by a joint research committee, or MKDG JRC, and a joint steering committee, or MKDG JSC, each of which is comprised of representatives of MKDG and the Company. Under the MKDG Agreement, MKDG has final decision-making authority over the MKDG JSC, which has the authority to decide matters that cannot be resolved by the MKDG JRC. MKDG may terminate the MKDG Agreement on a project-by-project basis or in its entirety upon 60 days’ prior written notice. Each party also has various termination rights under certain circumstances, including but not limited to patent challenges, insolvency, or a material breach by the other party, subject to certain conditions.

MKDG Agreement Accounting

The Company originally identifiedtwo performance obligations at the outset of the MKDG Agreement, represented by thetwo potential research and development targets. While the Company is obligated under the MKDG Agreement to provide the exclusive license and perform certain research activities, the Company determined that the license, the research activities, and participation on the MKDG JRC and MKDG JSC are considered promised services. Participation on the

MKDG JRC and MKDG JSC to oversee the research activities contemplated under the MKDG Agreement were determined to be quantitatively and qualitatively immaterial and, therefore, were excluded from the performance obligations. The total transaction price of the MKDG Agreement is allocated to the performance obligations based on their relative standalone selling price. The Company recognizes the transaction price allocated to the performance obligations as the research and development services are provided, using an input method, in proportion to costs incurred to date for each research development target as compared to total costs incurred and expected to be incurred in the future to satisfy the underlying obligation. Incremental fees for research and development services are paid at agreed upon FTE rates and recognized as revenue in the period incurred.

As of March 31, 2026, the total transaction price of $17.0 million is allocated to theone remaining performance obligation and $3.0 million remains unsatisfied.

Amounts due to the Company that have not yet been received are recorded as accounts receivable and amounts received that have not yet been recognized as revenue are recorded as deferred revenue on the Company’s condensed consolidated balance sheet.

Betta Pharma License and Collaboration Agreement

On May 29, 2023, the Company entered into a license and collaboration agreement, or the Betta Pharma License Agreement, with Betta Pharma to collaborateon the development, manufacturing, and commercialization of CFT8919 in Greater China, comprised of mainland China, Hong Kong SAR, Macau SAR and Taiwan, with the Company retaining rights to CFT8919 in the rest of the world other than Greater China, or the C4T Territory.

Under the terms of the Betta Pharma License Agreement, the Company grants Betta Pharma an exclusive license under certain of the Company's intellectual property rights to develop, manufacture and commercialize CFT8919 for all uses in humans in Greater China. Betta Pharma is responsible for all development, regulatory approval, manufacturing and commercialization costs in Greater China except where Betta Pharma acts as the Company's agent in Greater China in connection with a global trial sponsored by the Company. As part of the collaboration, Betta Pharma made an upfront cash payment of $10.0 million to the Company and has agreed to make up to $357.0 million in aggregate milestone payments, plus tiered royalties on net sales of CFT8919 in Greater China. These payments are subject to a withholding tax by the State Taxing Authority of the People's Republic of China. Royalties payable from Betta Pharma to the Company range from low to mid double-digit percent, subject to certain reductions under certain circumstances as described in the Betta Pharma License Agreement. In addition, as part of the collaboration, the Company has agreed to make milestone payments to Betta Pharma of up to $40.0 million following the Company's receipt of approval of a New Drug Application for CFT8919 from the FDA, with the milestone amount based on the percentage of patients in contemplated clinical trials that were enrolled by Betta Pharma and the line of therapy of the approval. In addition, the Company has agreed to pay Betta Pharma tiered royalties on net sales of CFT8919 in the C4T Territory in the low single digit percent range, subject to reductions under certain circumstances as described in the Betta Pharma License Agreement.

In connection with the execution of the Betta Pharma License Agreement, the Company, Betta Pharma, and an affiliate of Betta Pharma, (Betta Investment (Hong Kong) Limited, or Betta Investment), entered into a stock purchase agreement dated May 29, 2023, or the Betta Stock Purchase Agreement, and together with the Betta Pharma License Agreement, the Betta Agreements, pursuant to which Betta Investment agreed to purchase 5,567,928 shares of the Company's common stock, or the Betta Shares, for an aggregate purchase price of approximately $25.0 million, or $4.49 per share, which represented a 25% premium over the 60-trading-day volume weighted average closing price as oftwo trading days prior to the effective date of the Betta Stock Purchase Agreement. The Betta Stock Purchase Agreement has certain restrictions customary to agreements of this nature. The closing under the Betta Stock Purchase Agreement occurred on January 4, 2024. The $25.0 million of proceeds that the Company received were recorded as $20.0 million for the issuance of shares, with the remaining $5.0 million of premium paid on the share price recorded as consideration for revenue under the Betta Pharma License and Collaboration Agreement. The Betta Stock Purchase Agreement has certain restrictions customary to agreements of this nature.

The collaboration is managed by a joint steering committee, which is composed of representatives from both Betta Pharma and the Company. Following the completion of the dose escalation phase of the Phase 1 trial of CFT8919, Betta Pharma may terminate the Betta Pharma License Agreement for convenience upon at least 90 days’ prior written notice. Each party also has various termination rights under certain circumstances, including but not limited to regulatory safety stoppages, patent challenges, insolvency, or a material breach by the other party, subject to certain conditions.

Betta Agreements accounting

The Company expects to recognize revenue under the Betta Agreements from one type of arrangement, the licensing agreement. The Betta Agreements will consist of the following activities: (1) license of intellectual property, (2) clinical supply agreement, (3) manufacturing technology transfer, and (4) commercial manufacturing supply agreement. The clinical supply agreement, or the Betta Pharma Supply Agreement, was signed on August 31, 2024. The Company recognizes the transaction price allocated to the performance obligation as the costs related to manufactured clinical supply are incurred, using an input method, in proportion to costs incurred to date as compared to total costs incurred and expected to be incurred in the future to satisfy the underlying obligation. The clinical manufacturing costs are paid at agreed upon rates and included in the estimated transaction price. The estimated transaction price as of March 31, 2026 is $125.0 million, consisting of the $10.0 million upfront cash consideration, $5.0 million from the closing of the Betta Stock Purchase Agreement, a $2.0 million milestone achieved in December 2023 under the Betta Pharma License Agreement, and the estimated consideration expected to be received from the manufactured clinical supply of $108.0 million. This estimate includes a number of assumptions, including but not limited to the duration and total volume of clinical supply to be provided by the Company pursuant to the Betta Pharma Supply Agreement. In the event there are fluctuations in the Company's assumptions, the estimates of consideration expected to be received pursuant to the Betta Pharma Supply Agreement will also change. Due to scientific and technical uncertainties of the clinical trials, the Company cannot be certain that this amount will be recognized as revenue in future periods.

Amounts due to the Company that have not yet been received are recorded as accounts receivable and amounts received that have not yet been recognized as revenue are recorded as deferred revenue on the Company’s consolidated balance sheet.

Roche Collaboration and License Agreement

In March 2016, the Company entered into a license agreement with F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc., or Roche, which was amended in June 2016 and again in March 2017. The Company and Roche amended and restated that agreement (as so amended) in December 2018. This amended and restated agreement is referred to as the 2018 Roche Agreement. Under the 2018 Roche Agreement, the Company and Roche agreed to collaborate in the research, development, manufacture and commercialization of target-binding degrader medicines using the Company’s proprietary TORPEDO platform for the treatment of cancers and other indications. Under the 2018 Roche Agreement, the Company may elect to opt into certain co-development rights, in which case the Company will receive an increased royalty rate on future product sales from products directed to that target. In addition, if the Company opts into certain co-detailing rights, it is also entitled to reimbursement of certain commercialization costs. Upon entry into the 2018 Roche Agreement, the Company received additional upfront consideration of $40.0 million.

In November 2020, the Company signed a further amendment, the effect of which was to provide that the parties would develop up tofive potential targets, with Roche maintaining its option rights to license and commercialize products directed to those targets. The November 2020 amendment also provides a mechanism through which the Company and Roche can mutually agree to terminate the 2018 Roche Agreement on a target-by-target basis by the entry into a Mutual Target Termination Agreement. Upon the entry into a Mutual Target Termination Agreement, the 2018 Roche Agreement provides that all rights and responsibilities for know-how and other intellectual property in support of products that use inhibition as their mode of action revert to Roche and all rights and responsibilities for know-how and other intellectual property in support of products that use degradation as their mode of action revert to the Company. In support of this allocation of rights, Roche provides the Company, and the Company provides Roche, with a perpetual irrevocable, fully paid up, exclusive (even as to the party granting the license), sublicensable (including in multiple tiers) license to the patents and know-how that are allocated to a party under a Mutual Target Termination Agreement. As the research activities with Roche have progressed and evolved over time, there are nowtwo targets on which the parties continue to collaborate, with Roche maintaining its option rights to license and commercialize products directed to thosetwo targets. In December 2023, the Company signed a second amendment to the 2018 Roche Agreement, the effect of which was to update the terms of the agreement as it pertains to thetwo targets on which the parties continue to collaborate. Under the second amendment to the 2018 Roche Agreement, Roche retains its option rights to license and commercialize products directed to those targets but the timing of its option rights are adjusted to begin upon Roche's receipt of the dose range finding data package. There was no material impact to the accounting in 2023 as a result of the second amendment to the 2018 Roche Agreement.

Under the 2018 Roche Agreement, as amended, the Company receives annual research plan payments of $1.0 million for each active research plan. For thetwo targets that remain under collaboration among the parties, Roche is required to pay the Company fees of $2.0 million upon the progression of targets to the lead series identification achievement phase. In March 2025, the Company achieved this $2.0 million milestone for each of the active collaboration targets, which resulted in the addition of $4.0 million to the transaction price for the collaboration. In the event Roche exercises its option rights as to one of these targets, Roche is required to pay the Company an option exercise fee of $8.0 million.

Under the 2018 Roche Agreement, as amended, for each target option exercised by Roche, the Company is eligible to receive milestone payments up to $273.0 million upon the achievement of certain development milestones with respect to corresponding products, subject to certain reductions and exclusions based on intellectual property coverage. Roche is also required to pay the Company up to $150.0 million per target in one-time sales-based milestone payments upon the achievement of specified levels of net sales of a product directed to such target. Finally, Roche is required to pay the Company tiered royalties ranging from the mid-single digits to mid-teen percentages on net sales of products sold by Roche pursuant to its exercise of its option rights, subject to certain reductions. For sales of products for which the Company exercises its co-development right, the applicable royalty rates will be increased by a low-single digit percentage.

The collaboration is managed by a joint research committee, or the Roche JRC. The Company has control over the Roche JRC prior to Roche’s exercise of its option rights as to a particular target, with Roche assuming control of the Roche JRC thereafter, Roche may terminate the 2018 Roche Agreement on a target-by-target or product-by-product basis under several scenarios, upon at least 90 days’ prior written notice. Each party also has various termination rights under certain circumstances, including but not limited to insolvency or a material breach by the other party, subject to certain conditions.

Roche Agreement accounting

At commencement, the Company identified twelve performance obligations within the 2018 Roche Agreement, represented by thesix potential research and development targets then included in the collaboration and the option rights held by Roche for each of thosesix targets. A non-exclusive royalty-free license to use the Company’s intellectual property to conduct research and development activities and participation on the Roche JRC were identified as promised services. However, the Company determined that the research and development license and research and development services were not distinct from one another, and participation on the Roche JRC was determined to be quantitatively and qualitatively immaterial.

The total transaction price of the 2018 Roche Agreement is allocated to the performance obligations based on their relative standalone selling price. The allocated transaction price is recognized as revenue from collaboration agreements in one of two ways:

•Research and development targets: The Company recognizes the portion of the transaction price allocated to each of the research and development performance obligations as the research and development services are provided, using an input method, in proportion to costs incurred to date for each research development target as compared to total costs incurred and expected to be incurred in the future to satisfy the underlying obligation related to said research and development target. The transfer of control occurs over this period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation.

•Option rights: The transaction price allocated to the options rights, which are considered material rights, is recognized in the period that Roche elects to exercise or elects to not exercise its option right to license and commercialize the underlying research and development target.

The following table summarizes the allocation of the total transaction price to the identified performance obligations under the arrangement, and the amount of the transaction price unsatisfied as of March 31, 2026 (in thousands):

Amounts due to the Company that have not yet been received are recorded as accounts receivable and amounts received that have not yet been recognized as revenue are recorded as deferred revenue on the Company’s condensed consolidated balance sheet.

Biogen Collaboration Research and License Agreement

In December 2018, the Company entered into a collaboration research and license agreement, or the Biogen Agreement, with Biogen MA, Inc., or Biogen. In February 2020, the Company and Biogen amended the Biogen Agreement to provide further clarity around Biogen’s ownership of target binding moieties (which are portions of molecules), and any related intellectual property that are directed at or bind to collaboration targets. This amendment further provided that Biogen licenses to the Company rights to use these Biogen target binding moieties and any related intellectual property as needed in order to conduct the research and development activities contemplated under the Biogen Agreement. Pursuant to the terms of the Biogen Agreement, the Company and Biogen agreed to collaborate on research activities to develop novel treatments for neurological conditions such as Alzheimer's disease and Parkinson's disease through medicines that rely on target protein degradation, or TPD, as their mode of action, all of which are created using the Company’s degrader technology. Under the terms of the Biogen Agreement, the Company was engaged to develop TPD therapeutics that utilize degrader technology for up tofive target proteins over a period of 54 months, ending in June 2023. On a target-by-target basis, after successful completion of a defined target evaluation period, Biogen assumes full rights and responsibility for continued development of each target. As of June 30, 2024, the research term of the Biogen Agreement has been fully satisfied.

In exchange for the non-exclusive research license from Biogen, as well as a $45.0 million nonrefundable upfront payment, the Company has granted Biogen a license to develop, commercialize, and manufacture products related to each of the targets (which is contingent on the parties not terminating the agreement), performs initial research services for drug discovery, has provided a non-exclusive research and commercial license to its intellectual property, and participates on the joint steering committee, or the Biogen JSC. For any target, following the achievement of development candidate criteria and prior to any IND-enabling study, Biogen will bear all costs and expenses of and will have sole discretion and decision-making authority with respect to the performance of further activities with respect to any degrader under development under the Biogen Agreement and all products that incorporate that degrader. Biogen is also required to pay the Company up to $35.0 million per target in development milestones and $26.0 million per target in one-time sales-based payments for the first product to achieve certain levels of net sales. In addition, Biogen is required to pay the Company royalties on a licensed product-by-licensed product basis, on worldwide net product sales. All milestone and sales-based payments are made after the Company has met the defined criteria in the joint research plan for that target, at which time Biogen will have control of the products related to the targets for commercialization; the receipt of these payments is contingent on the further development of products directed to the targets to commercialization by Biogen, without any additional research and development efforts from the Company.

In February 2026, the Company earned a $2.0 million milestone from Biogen after Biogen advanced BIIB145, a BTK degrader, that the Company delivered to Biogen, into the clinic. In September 2025, the Company earned a $2.0 million milestone from Biogen after Biogen advanced BIIB142, a development candidate for IRAK4 that the Company delivered to Biogen, into the clinic. The Company's performance obligation under the Biogen Agreement was fully satisfied as of March 2024 and the transaction price has been fully allocated.

Merck License and Collaboration Agreement

On December 11, 2023, the Company and Merck Sharp & Dohme, LLC, or Merck, entered into an exclusive license and collaboration agreement, the Merck Agreement, to develop degrader-antibody conjugates, or DACs, an emerging modality designed to selectively target and neutralize disease-causing proteins in cancer cells. The Merck Agreement was terminated by Merck, effective late November 2025.

Under the terms of the Merck Agreement, the Company received a$10.0 million upfront payment. The Company and Merck collaborated to develop DACs directed to an initial undisclosed oncology target that was exclusive to the collaboration. The performance obligation under the Merck Agreement was fully satisfied upon the termination of the agreement in 2025 and the transaction price has been fully allocated.

Revenue from collaboration agreements for the three months ended March 31, 2026 and 2025 in the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands):

Financial information related to the collaboration and license agreements consisted of the following in the Company’s condensed consolidated balance sheet as of March 31, 2026 (in thousands):

Financial information related to the collaboration and license agreements consisted of the following in the Company’s condensed consolidated balance sheet as of December 31, 2025 (in thousands):

Supplemental financial information related to the collaboration and license agreements for the three months ended March 31, 2026 and 2025 are (in thousands):

As of March 31, 2026, the aggregate amount of the transaction price allocated to performance obligations under the MKDG Agreement, Betta Agreements, and Roche Agreement that were partially unsatisfied was $132.1 million. The vast majority of the remaining transaction price to be recognized as revenue is based on the estimated manufactured clinical supply costs under the Betta Pharma collaboration. Due to scientific and technical uncertainties of the clinical trials, the Company cannot be certain that this amount will be recognized as revenue in future periods.

Note 9. Stockholders’ equity

At-The-Market Equity Program

In October 2024, the Company filed a registration statement on Form S-3, or the 2024 Registration Statement, with the SEC that became effective in November 2024 and registered the offering, issuance and sale of an unspecified amount of common stock, preferred stock, debt securities, warrants and/or units of any combination thereof. Simultaneously, the Company entered into a sales agreement with TD Securities (USA) LLC, as sales agent, to provide for the issuance and sale by the Company of up to $200.0 million of common stock from time to time in “at-the-market” offerings under the 2024 Registration Statement and related prospectus filed with the 2024 Registration Statement, or the 2024 ATM Program. In October 2025, the Company terminated the sales agreement prospectus related to the 2024 ATM Program. A total of 3,769,483 shares of the Company's common stock at an average purchase price of $2.55 had been sold through the 2024 ATM Program, as of October 16, 2025, which sales resulted in net proceeds of $9.4 million.

In November 2025, the Company filed a registration statement on Form S-3, or the 2025 Registration Statement, with the SEC that became effective in December 2025 and registered the offering, issuance and sale of up to $400.0 million of common stock, preferred stock, debt securities, warrants and/or units or any combination thereof, together with a sales agreement prospectus for the offer and sale of up to $125.0 million of common stock from time to time in “at-the-market” offerings under the 2025 Registration Statement and related prospectus filed with the 2025 Registration Statement, or the 2025 ATM Program. No sales have been made under the 2025 ATM program for the three months ended March 31, 2026.

Certificate of Amendment to Fifth Amended and Restated Certificate of Incorporation

In June 2025, the Company's stockholders approved, and the Company filed, an amendment to the Company's Fifth Amended and Restated Certificate of Incorporation to increase the number of authorized shares of common stock from 150,000,000 to 300,000,000. The certificate of amendment, which was filed with the Secretary of State of the State of Delaware, became effective in June 2025.

Underwritten Offering

In October 2025, the Company entered into an underwriting agreement, or the Underwriting Agreement, with Jefferies LLC, TD Securities (USA) LLC and Evercore Group L.L.C., or collectively, the Underwriters, related to an underwritten offering, or the 2025 Offering, of (i)21,895,000 shares, or the Shares, of the Company’s common stock, par value $0.0001 per share, or the Common Stock; (ii) in lieu of Common Stock to certain investors, pre-funded warrants to purchase an aggregate of 28,713,500 shares of Common Stock, or the Pre-Funded Warrants; (iii) accompanying Class A warrants to purchase an aggregate of 50,608,500 shares of Common Stock (or pre-funded warrants in lieu thereof), or the Class A Warrants, and together with the Class B Warrants (as defined below), the Class A and Class B Warrants; and (iv) accompanying Class B warrants to purchase an aggregate of 50,608,500 shares of Common Stock (or pre-funded warrants in lieu thereof), or the Class B Warrants, and together with the Pre-Funded Warrants and the Class A Warrants, the Warrants. Each Share was offered and sold together with accompanying Class A and Class B Warrants each exercisable forone share of Common Stock at a combined offering price of $2.47 per Share and accompanying Class A and Class B Warrants, and each Pre-Funded Warrant was offered and sold together with accompanying Class A and Class B Warrants at a combined offering price of $2.4699 per Pre-Funded Warrant and accompanying Class A and Class B Warrants. The Company received net proceeds from the Offering, after deducting the underwriting discount and commissions and estimated offering expenses, of approximately $116.9 million. If all Warrants are exercised, the aggregate net proceeds to the Company from the Offering, after deducting underwriting discounts and commissions and estimated offering expenses, are expected to be $341.7 million. See Note 10 for details on the Warrants.

Note 10. Warrants

In connection with the 2025 Offering, the Company issued 28,713,500 Pre-Funded Warrants, which have an initial exercise price per share of $0.0001, subject to certain adjustments. Each Pre-Funded Warrant can be exercised forone share of common stock. The Pre-Funded Warrants may be exercised at any time after the date of issuance by cash or cashless exercise, at the holder’s election, until all of the Pre-Funded Warrants are exercised in full, subject to a beneficial ownership limitation. The Pre-Funded Warrants do not expire.

In connection with the 2025 Offering, the Company issued 50,608,500 Class A Warrants that can be exercised either forone share of common stock at an initial exercise price per share of $2.22 or forone pre-funded warrant for an exercise price of $2.2199, subject to certain adjustments. Each Class A Warrant is exercisable immediately and will expire on the earlier of (i) 30 calendar days following the public release of nine-month median follow-up data from any expansion cohort in the Company’s planned Phase 1b trial of cemsidomide with elranatamab and (ii) the fifth anniversary of the date of issuance.

In connection with the 2025 Offering, the Company issued 50,608,500 Class B Warrants that can be exercised either forone share of common stock at an initial exercise price per share of $2.22 or forone pre-funded warrant for an exercise price of $2.2199, subject to certain adjustments. Each Class B Warrant is exercisable immediately and expires on the fifth anniversary of the date of issuance; provided that the Company may require the mandatory exercise of the Class B Warrants on or after thesix-month anniversary of the date of issuance and so long as the per share closing price of the Common Stock on The Nasdaq Global Select Market on each of theten consecutive trading days prior to the date of the Company’s notice of mandatory exercise is above $6.66, subject to certain adjustments.

The Class A and Class B Warrants are exercisable solely by means of a cash exercise; provided that, if, at the time a holder exercises its Class A Warrants, there is no effective registration statement registering, with a current prospectus available for, the issuance of the shares of Common Stock underlying such Class A or Class B Warrant or prior consent has been provided by the Company, then a holder may elect to exercise such warrant through cashless exercise pursuant to the terms of the applicable warrant agreement. If the Company consents to a cashless exercise for a holder of Class A or Class B Warrants, a similar allowance for cashless exercise shall be provided to all holders of the same class of warrants.

All Warrants are classified as equity and the following table summarizes the warrant activity for the three months ended March 31, 2026:

Note 11. Stock-based compensation

Stock-based compensation expense for the three months ended March 31, 2026 and 2025 was classified in the Company’s condensed consolidated statement of operations and comprehensive loss as follows (in thousands):

Stock options

During the three months ended March 31, 2026, the Company granted stock options for the purchase of 76,780 shares of common stock with a weighted average exercise price of $1.88 per share and a weighted average grant-date fair value of $1.50 per share. As of March 31, 2026, the unrecognized compensation cost related to outstanding stock options was $10.2 million, which is expected to be recognized over a weighted-average period of 2.0 years.

On March 7, 2024, the Company approved an option repricing program applicable to outstanding option awards granted to current employees of the Company under the Company’s 2020 Stock Option and Incentive Plan, or the 2020 Plan, with an exercise price per share greater than or equal to $22.00. On October 7, 2024, the 2020 Plan was amended to prohibit the plan's administrator from reducing the exercise price of outstanding stock options or stock appreciation rights or effecting repricing through cancellation and re-grant or cancellation in exchange for cash or other awards without prior stockholder approval.

Performance-accelerated restricted stock units

During the three months ended March 31, 2026, the Company’s Board of Directors authorized the issuance of 1,588,140 performance-accelerated restricted stock units, or PARSUs, to certain employees, including members of the Company’s leadership team under the 2020 Plan. PARSUs are valued on the grant date using the grant date market price of the underlying shares. The PARSUs will vest in tranches at the earlier of the achievement of certain discovery and clinical milestones, or February 13, 2029. Upon vesting, each PARSU automatically converts intoone share of the Company's common stock. No PARSUs vested during the three months ended March 31, 2026. As of March 31, 2026,1,588,140 PARSUs remained outstanding, and the unrecognized compensation cost related to outstanding PARSUs was $2.9 million, which is expected to be recognized over a weighted-average period of 2.9 years.

Time-based restricted stock units

During the three months ended March 31, 2026, the Company issued 2,829,710 restricted stock units, or RSUs, that were subject to time-based vesting conditions to its employees. RSUs are valued on the grant date using the grant date market price of the underlying shares. A total of 712,681 RSUs vested during the three months ended March 31, 2026 on their respective vesting schedules. Upon vesting, each RSU automatically converts intoone share of the Company’s common stock. During the three months ended March 31, 2026, the Company indirectly repurchased 105,756 shares of its common stock through net-share settlement as consideration for employee tax withholding obligations arising upon vesting of the RSUs, which tax amounts were remitted to the applicable revenue authorities by the Company in cash on behalf of the RSU holders. As of March 31, 2026, there were a total of 4,467,051 RSUs outstanding and the unrecognized compensation cost related to outstanding RSUs was $11.8 million, which is expected to be recognized over a weighted-average period of 2.7 years.

Note 12. Commitments and contingencies

Legal proceedings

The Company is not currently a party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings.

Note 13. Loss per share

For periods in which the Company reports a net loss attributable to common stockholders, potentially dilutive securities have been excluded from the computation of diluted net loss per share as their effects would be anti-dilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. For purposes of the dilutive net loss per share calculation, stock options, and restricted stock units for which the performance or market vesting conditions have been met are considered to be common stock equivalents, while restricted stock units with performance or market vesting conditions that were not met as of March 31, 2026 are not considered to be common stock equivalents. The Company excluded the following potential common shares presented based on amounts outstanding at period end from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect:

Basic and diluted loss per share is computed by dividing net loss by the weighted-average common shares outstanding for the three months ended March 31, 2026 and 2025 (in thousands, except share and per share data):

Note 14. Income taxes

For the three months ended March 31, 2026 and 2025, the Company recordedno income tax provision or benefit due to losses generated where no benefit was recorded due to the valuation allowance. The Company continues to maintain a full valuation allowance for its U.S. federal and state deferred tax assets as of March 31, 2026 due to uncertainty regarding future taxable income.

Note 15. Segment reporting

The Company operates asone operating segment. The Company's chief operating decision maker, or CODM, is its chief executive officer, who reviews financial information presented on a consolidated basis. The CODM manages and allocates resources to the operations of our company on a total company basis by assessing the overall level of resources available and how to best deploy these resources across functions and research and development projects that are in line with our long-term company-wide strategic goals. Consistent with this decision-making process, the CODM uses operating expenses to monitor budget versus actual results for purposes of evaluating performance and to make decisions about the allocation of resources. The CODM does not utilize revenue in their decision-making process as a significant amount of the revenues recognized by the Company are derived from the upfront payments received from our collaboration partners (see Note 8 for further details).

These financial metrics used by the CODM to make key operating decisions consist of development, research, and general and administrative expenses.

The following table presents selected financial information with respect to the Company’s single operating segment for the three months ended March 31, 2026 and 2025.

(1)The reconciling items include revenue and stock-based compensation expense for the three months ended March 31, 2026 and 2025, respectively.

Note 16. Subsequent Events

On April 8, 2026, the Company entered into a Research Collaboration and License Agreement, or the 2026 Roche Agreement, with Roche to collaborate on the discovery, development and commercialization of DACs. The Company and Roche have a pre-existing material relationship arising from the 2018 Roche Agreement.

Pursuant to the terms of the 2026 Roche Agreement, the Company granted Roche a worldwide, exclusive license under certain of the Company's intellectual property rights to develop, manufacture and commercialize DACs directed totwo initial undisclosed oncology targets. After the collaboration term and a decision by Roche to proceed with development, Roche is solely responsible for all development, regulatory approval, manufacturing and commercialization costs. Under the terms of the 2026 Roche Agreement, Roche has made an upfront cash payment of $20.0 million. In addition, across the collaboration, C4T is eligible to receive over $1.0 billion in aggregate development, regulatory and commercial milestone payments, plus tiered royalties on net sales.