Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and results of operations together with our consolidated financial statements and the related notes appearing elsewhere in this Annual Report on Form 10-K. This discussion and other parts of this Annual Report on Form 10-K contain forward-looking statements that involve risks and uncertainties, such as statements regarding our plans, objectives, expectations, intentions and projections. Our actual results could differ materially from those discussed in these forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, those discussed in the “Risk Factors” section of this Annual Report on Form 10-K.

Overview

We are a biopharmaceutical company developing potential first- or best-in-class, high-impact therapies for autoimmune diseases and cancer. We pursue promising therapeutic targets while leveraging core expertise in T cell engagers, which are established in oncology and are now advancing into autoimmune diseases. With a clinical-stage pipeline built on a rigorous scientific approach and purposeful innovation, we are advancing our mission to deliver new standards of care for patients.

Immunology

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CLN-978 is a CD19xCD3 bispecific T cell engager that we are developing for autoimmune diseases. In the Phase 1 OUTRACE Program, CLN-978 is being evaluated in patients with systemic lupus erythematosus (“SLE”), rheumatoid arthritis (“RA”), and Sjögren’s disease (“SjD”). The OUTRACE SLE Study is an ongoing global Phase 1 clinical trial in patients with moderate to severe SLE. The OUTRACE RA Study is a Phase 1 clinical trial in patients with active, difficult-to-treat RA, which is ongoing in Europe. We plan to share initial clinical data in SLE RA in the second quarter of 2026 and repeat dosing data in RA in the third quarter of 2026. The OUTRACE SjD Study is an ongoing global Phase 1 clinical trial in patients with active, moderate to severe Sjögren’s disease. We plan to share initial clinical data in Sjögren’s disease in the fourth quarter of 2026.

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Velinotamig is a BCMAxCD3 bispecific T cell engager that we are developing for autoimmune diseases. Chongqing Genrix Biopharmaceutical Co., Ltd. ("Genrix"), from which we licensed velinotamig, is enrolling a Phase 1 clinical trial in China in patients with autoimmune diseases, initially in patients with SLE, followed by planned future expansion into other indications, and initial clinical data will be shared in the fourth quarter of 2026. We intend to use the data generated from this Phase 1 clinical trial to accelerate global clinical development. Following the completion of the Genrix Phase 1 clinical trial, we will conduct all further development of velinotamig in autoimmune diseases.

Oncology

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CLN-049 is a FLT3xCD3 bispecific T cell engager. CLN-049 is being evaluated in an ongoing Phase 1 clinical trial in patients with relapsed/refractory acute myeloid leukemia ("AML") or myelodysplastic syndrome (“MDS”). At the 2025 American Society for Hematology (“ASH”) Annual Meeting, we shared monotherapy efficacy data from the ongoing dose escalation portion of the trial in a heavily pretreated all-comer population of patients with relapsed/refractory AML. We plan to share a clinical data update from the dose escalation portion of the trial in the second half of 2026. We also plan to begin enrolling dose expansion cohorts in the second quarter of 2026 and expect to complete enrollment in the fourth quarter of 2026 to determine the recommended Phase 2 dose for an expected single-arm pivotal registrational trial.

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Zipalertinib (CLN-081/TAS6417), on which we are collaborating with an affiliate of Taiho Pharmaceutical Co., Ltd. ("Taiho"), is an orally-available small-molecule, irreversible epidermal growth factor receptor ("EGFR") inhibitor that is designed to selectively target cells expressing EGFR exon 20 insertion mutations (“EGFR ex20ins”) with relative sparing of cells expressing wild-type EGFR.

We are evaluating zipalertinib in the pivotal Phase 2b portion of the REZILIENT1 clinical trial in patients with EGFR ex20ins non-small cell lung cancer ("NSCLC") who progressed after prior systemic therapy. In February 2026, based on the primary efficacy data from REZILIENT1, Taiho completed a rolling submission of a new drug application (“NDA”) seeking accelerated approval of zipalertinib for the treatment of patients with locally advanced or metastatic EGFR ex20ins NSCLC who have previously received platinum-based systemic chemotherapy.

Taiho is evaluating zipalertinib in a global Phase 3 clinical trial (“REZILIENT3”) in combination with chemotherapy as a potential first-line treatment for locally advanced or metastatic EGFR ex20ins NSCLC adult patients. Taiho completed enrollment of the trial in February 2026 and expects to obtain top-line results by the end of 2026.

Taiho is also evaluating zipalertinib in a Phase 2 parallel cohort trial (“REZILIENT2”). Taiho shared emerging data from certain REZILIENT2 cohorts at the International Association for the Study of Lung Cancer (“IASLC”) 2025 World Conference on Lung Cancer (“WCLC”) and European Society for Medical Oncology (“ESMO”) Congress 2025.

Preclinical Programs

In addition to the product candidates described above, we are actively developing several preclinical programs in autoimmune diseases and oncology.

Recently Discontinued Program

CLN-619 is a MICA/B monoclonal antibody that we were previously evaluating in Phase 1 clinical trials. In May 2025, following a review of the CLN-619 data from the disease-specific expansion cohorts for endometrial and cervical cancers, we announced discontinuation of further development of CLN-619 in patients with gynecological cancers as preliminary results did not meet our internal threshold for advancement. In November 2025, after a review of the emerging clinical data in patients with NSCLC and multiple myeloma, we discontinued further development of CLN-619.

CLN-617 is an interleukin-2 and interleukin-12 fusion protein that we were previously evaluating in a Phase 1 clinical trial. In November 2025, after a review of the emerging clinical data in patients with advanced solid tumors, we discontinued further development of CLN-617.

CLN-418 is a B7H4x4-1BB bispecific antibody that we licensed from Harbour BioMed US Inc. (“Harbour”) and were previously evaluating in a Phase 1 clinical trial. In August 2024, following a review of the data from the Phase 1 clinical trial in solid tumors, we notified Harbour of our decision to terminate the license and collaboration agreement for CLN-418 (the “Harbour License Agreement”), effective November 2024. In connection with the termination of the Harbour License Agreement, we discontinued development of CLN-418 and returned development and commercial rights for CLN-418 to Harbour.

Intellectual Property

We directly hold the worldwide intellectual property rights for CLN-978. We hold the worldwide, excluding mainland China, Hong Kong, Macau and Taiwan (collectively referred to as “greater China”), intellectual property rights for velinotamig. We hold the worldwide intellectual property rights for CLN-049 through a development subsidiary that we had a 98% ownership interest in as of December 31, 2025. We are co-developing zipalertinib, for which Taiho holds the intellectual property rights, with an affiliate of Taiho. We hold the worldwide intellectual property rights or exclusive options for worldwide intellectual property for our early-stage programs.

Financing and Business Operations

Since our inception in 2016, we have focused all of our efforts and financial resources on raising capital, organizing and staffing our company, identifying, acquiring or in-licensing and developing product and technology rights, establishing and protecting our intellectual property portfolio, and developing and advancing our programs. We do not have any products approved for sale and have not generated any revenue from product sales.

We have funded our operations primarily through the sale of equity securities and from licensing or selling the rights to our product candidates. As of December 31, 2025, we have received net proceeds of $842.2 million from equity financings, $275.0 million from the sale of our equity interest in our zipalertinib development subsidiary to Taiho, and $18.9 million in revenue from a previous license agreement.

As of December 31, 2025, we had cash, cash equivalents, and short-term investments of $377.9 million, and long-term investments and interest receivable of $61.1 million. Interest receivable is included in prepaid expenses and other current assets on the consolidated balance sheets and represents accrued and unpaid interest on our marketable securities. We have a history of significant operating losses and have had negative cash flows from operations since our inception. As of December 31, 2025, we had an accumulated deficit of $588.1 million. We expect to continue to generate operating losses for the foreseeable future. Our future viability is dependent on the success of our research and development and our ability to access additional capital to fund our operations. There can be no assurance that our current operating plan will be achieved or that additional funding will be available on terms acceptable to us, or at all.

We are subject to risks and uncertainties common to early-stage companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the ability to obtain additional capital to fund operations. Our current and future product candidates will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require additional capital, adequate personnel and extensive compliance-reporting capabilities. There can be no assurance that our research and development will be successfully completed, that adequate protection for our intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable.

Components of Our Results of Operations

Revenue

We have not generated any revenue from the sale of products since our inception.

Research and Development Expenses

Research and development expenses consist primarily of costs incurred in connection with the research and development of our product candidates and programs. These expenses include:

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compensation costs for employees engaged in research and development functions;

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expenses incurred under agreements with organizations that support our drug discovery and development activities;

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expenses incurred in connection with the preclinical and clinical development of our product candidates and programs, including under agreements with contract research organizations ("CROs");

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costs related to contract manufacturing organizations that are primarily engaged to provide drug substance, raw materials, and drug product for our clinical trials, research and development programs, as well as investigative sites and consultants that conduct our clinical trials, nonclinical studies, and other scientific development services;

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the costs of acquiring and manufacturing nonclinical and clinical trial materials, including manufacturing registration and validation batches;

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costs related to compliance with quality and regulatory requirements;

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payments made under third-party licensing agreements; and

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direct and allocated costs related to facilities, information technology, personnel and other overhead.

Pursuant to a co-development agreement, we are collaborating with a Taiho affiliate to develop zipalertinib for the treatment of a genetically defined subset of patients with NSCLC, and Taiho will commercialize zipalertinib. For the agreed-upon indication, we and Taiho share development costs equally, and each party will receive 50% of any future potential pre-tax profits from U.S. sales of zipalertinib. For any additional indications that Taiho chooses to develop independently, Taiho will bear all development costs until they have sufficient data from such indication to support a commercial purpose or submission of zipalertinib for the additional indication. At such time, 50% of Taiho’s independent development costs, subject to certain adjustments, will be deducted from future pre-tax profits for potential U.S. sales of zipalertinib. In November 2025, Taiho independently initiated an ongoing global Phase 3 clinical trial evaluating zipalertinib in an additional indication.

General and Administrative Expenses

General and administrative expenses consist primarily of compensation costs for personnel in executive management, finance, legal, corporate and business development, and other administrative functions. General and administrative expenses also include legal fees relating to patent and corporate matters; professional fees for accounting, auditing, tax, and administrative consulting services; insurance costs; administrative travel expenses; marketing expenses; and other operating costs.

Other Income

Other income consists primarily of interest income earned on our cash, cash equivalents, and investments.

Income Taxes

In July 2025, the U.S enacted the budget reconciliation bill H.R. 1 into law, which included significant changes to U.S. income tax laws. We have assessed the impacts of H.R. 1 for 2025 and determined that there was no impact on our 2025 effective tax rate. Income taxes consist primarily of federal and state income taxes.

Results of Operations

Comparison of 2025 and 2024

The following table presents our results of operations for 2025 and 2024 (in thousands):

Operating expenses:

Other income (expense):

Other income (expense), net (443 ) (199 )

Income tax expense — 117

Net loss attributable to noncontrolling interests — (192 )

Research and Development Expenses

The following table summarizes our research and development expenses for 2025 and 2024 (in thousands):

Research and development personnel and operations 39,986 31,532

The $44.5 million increase in research and development expenses in 2025 compared to 2024 was primarily due to the one-time upfront in-licensing fee for velinotamig ($20.0 million), increases in clinical development costs ($21.9 million), personnel costs relating to higher average headcount during 2025 ($8.2 million), and equity-based compensation expense ($0.5 million), offset partially by decreases in preclinical costs ($3.7 million), and chemistry, manufacturing and controls costs ($2.4 million).

General and Administrative Expenses

The $0.2 million increase in general and administrative expenses in 2025 compared to 2024 was primarily due to increases in professional fees ($1.7 million), and legal costs ($1.6 million), offset partially by decreases in equity-based compensation expense ($2.2 million), and personnel costs ($1.0 million).

Other Income

The $7.7 million decrease in other income in 2025 compared to 2024 was primarily related to lower interest income earned.

Income Tax Expense (Benefit)

We did not record income tax expense or benefit in 2025 due to our net loss before income taxes in the current year and expected losses in future years. The income tax expense recognized for 2024 was driven by the finalization of estimates upon filing our 2023 tax return for the utilization of federal research and development credits generated during 2023 that were carried back to tax year 2022.

Net Loss Attributable to Noncontrolling Interests

Net loss attributable to noncontrolling interests is determined as the difference in the noncontrolling interests in the consolidated balance sheets between the start and end of each reporting period, after taking into account any capital transactions between our development subsidiaries and third parties.

Liquidity and Capital Resources

Overview

We have a history of significant operating losses and have had negative cash flows from operations since our inception and expect to continue to generate operating losses for the foreseeable future. We have not yet commercialized any products, and we do not expect to generate revenue from sales of products for several years, if at all. To date, we have funded our operations primarily with proceeds from the sale of equity securities and from licensing or selling the rights to our product candidates. As of December 31, 2025, we had cash, cash equivalents, and short-term investments of $377.9 million, and long-term investments and interest receivable of $61.1 million.

In June 2025, we entered into a license agreement with Genrix (the "Genrix License Agreement"), pursuant to which Genrix granted us a global (excluding greater China), exclusive license to develop and commercialize velinotamig, a BCMAxCD3 bispecific T cell engager, in all fields of use. Under the terms of the Genrix License Agreement, we paid Genrix an upfront license fee of $20.0 million in June 2025. Refer to Note 6 of our notes to the consolidated financial statements in this Annual Report on Form 10-K for additional detail regarding the Genrix License Agreement.

In April 2024, we completed a private placement (the "2024 Private Placement") in which we issued approximately 14.4 million shares of our common stock and pre-funded warrants to purchase approximately 0.3 million additional shares of our common stock. We received net proceeds of $262.7 million from the 2024 Private Placement, after deducting offering costs of $17.3 million. Refer to Note 7 of our notes to the consolidated financial statements in this Annual Report on Form 10-K for additional detail regarding the 2024 Private Placement.

We have an at-the-market equity offering program (the "ATM") through an agreement established with Cowen and Company, LLC (“Cowen”) in May 2023, pursuant to which we may offer and sell up to $125.0 million of our common stock from time to time through Cowen, acting as our sales agent. We made no sales under the ATM in 2025. Through December 31, 2025, we have sold approximately 3.3 million shares under the ATM and received net proceeds of $38.4 million, after deducting commissions. As of December 31, 2025, we had $85.6 million in shares of our common stock remaining under the ATM.

Cullinan is eligible to receive a $30.0 million payment from Taiho upon U.S. regulatory approval of zipalertinib for the treatment of patients with locally advanced or metastatic EGFR ex20ins NSCLC who have previously received platinum-based systemic chemotherapy. Cullinan is also eligible to receive up to a $100.0 million payment from Taiho upon U.S. regulatory approval of zipalertinib for the first-line treatment for adult patients with locally advanced or metastatic EGFR ex20ins NSCLC. We and Taiho will each receive 50% of any future pre-tax profits from potential U.S. sales of zipalertinib.

Cash Flows

Comparison of 2025 and 2024

The following table summarizes our sources and uses of cash for 2025 and 2024 (in thousands):

Net cash used in operating activities $ (175,750 ) $ (145,303 )

Net cash provided by (used in) investing activities 179,989 (136,314 )

Net cash provided by financing activities 1,088 266,188

Net decrease in cash and cash equivalents $ 5,327 $ (15,429 )

Cash Flow from Operating Activities

During 2025, our operating activities used $175.8 million of cash, which primarily consisted of our operating expenses, excluding non-cash items, of $205.3 million, partially offset by interest income, excluding accretion on marketable securities, of $15.9 million, $11.1 million net change in our non-tax operating assets and liabilities, and income tax refunds of $3.0 million. The non-cash operating expenses primarily consisted of equity-based compensation expense.

During 2024, our operating activities used $145.3 million of cash, which primarily consisted of our operating expenses, excluding non-cash items, of $158.8 million and a $2.8 million net change in our non-tax operating assets and liabilities, partially offset by interest income, excluding accretion on marketable securities, of $14.2 million, and an income tax refund of $2.3 million. The non-cash operating expenses primarily consisted of equity-based compensation expense.

Cash Flow from Investing Activities

During 2025, our investing activities provided $180.0 million, which consisted primarily of $416.6 million of proceeds from the maturities of marketable securities, partially offset by $236.5 million of purchases of marketable securities.

During 2024, our investing activities used $136.3 million, which consisted of $721.1 million of purchases of marketable securities, partially offset by $584.8 million of proceeds from the maturities of marketable securities.

Cash Flow from Financing Activities

During 2025, our financing activities provided $1.1 million of cash, which consisted of net proceeds from the issuance of common stock under equity-based compensation plans.

During 2024, our financing activities provided $266.2 million, which consisted of $262.7 million of net proceeds from the issuance of common stock under our 2024 Private Placement and $8.0 million in net proceeds from the issuance of common stock under our equity-based compensation plans, partially offset by $4.4 million paid to acquire shares and options to purchase shares of our CLN-619 development subsidiary that were held by noncontrolling interests.

Future Funding Requirements

We expect our expenses to continue to increase in connection with our ongoing activities, particularly as we:

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continue research and development of our current and future product candidates and programs;

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conduct preclinical studies and clinical trials for our current and future product candidates;

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experience any delays or encounter any issues with any of the above, including but not limited to failed studies, or trials, complex results, safety issues, or other regulatory challenges;

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develop the necessary processes, controls, and manufacturing capabilities to obtain marketing approval for our current and future product candidates and to support manufacturing on a commercial scale;

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develop and implement plans to establish and operate in-house manufacturing operations and facilities, if deemed appropriate;

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seek regulatory approvals for our current and future product candidates that successfully complete clinical trials;

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hire and retain additional personnel, such as nonclinical, clinical, pharmacovigilance, quality assurance, regulatory affairs, manufacturing, distribution, legal, compliance, medical affairs, finance, general and administrative, commercial, and scientific personnel; and

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develop, maintain, expand, and protect our intellectual property portfolio.

Based on our current operational plans and assumptions, we expect that our current cash, cash equivalents, investments, and interest receivable will be sufficient to fund operations into 2029. We have based these estimates on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect. As we progress with our development programs and the regulatory review process, we expect to incur significant expenses related to product manufacturing, pre-commercial activities and commercialization. We may also require additional capital to pursue in-licenses or acquisitions of other programs to further expand our pipeline.

Because of the numerous risks and uncertainties associated with research, development and commercialization of our product candidates and programs, we are unable to estimate the exact amount of our working capital requirements. Our future funding requirements will depend on and could increase significantly as a result of many factors, including:

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the scope, progress, results, and costs of drug discovery, laboratory testing, and preclinical and clinical development for our current and future product candidates;

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timely completion of our preclinical studies and clinical trials, which may be significantly slower or cost more than we currently anticipate and will depend substantially upon the performance of third-party contractors;

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the prevalence, duration, and severity of potential side effects or other safety issues experienced by patients receiving our current and future product candidates;

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our ability to establish and maintain collaborations and license agreements on favorable terms, if at all, and the extent to which we acquire or in-license technologies or programs, if at all;

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our ability to enroll clinical trials in a timely manner and to quickly resolve any delays or clinical holds that may be imposed on our development programs;

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the costs of expanding our facilities to accommodate our expected growth in personnel;

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our ability and the ability of third parties with whom we contract to manufacture adequate clinical and commercial supplies of our current and future product candidates, remain in good standing with regulatory authorities and develop, validate, and maintain commercially viable manufacturing processes that are compliant with current good manufacturing practices;

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the costs of preparing, filing, and prosecuting patent applications, maintaining and enforcing our intellectual property rights, and defending intellectual property-related claims;

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the extent to which we acquire or in-license technologies or programs;

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the sales price and availability of adequate third-party coverage and reimbursement for our product candidates, if and when approved; and

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the ongoing costs of operating as a public company.

Until such time, if ever, that we can generate product revenue sufficient to achieve profitability, we expect to finance our cash needs through equity offerings, debt financings, government or other third-party funding, marketing and distribution arrangements, and other collaborations, strategic alliances and licensing arrangements. To the extent that we raise additional capital through the sale of equity, current ownership interests will be diluted. If we raise additional funds through government or third-party funding, collaboration agreements, strategic alliances, licensing arrangements, or marketing and distribution arrangements, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates, or grant licenses on terms that may not be favorable to us. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures, or declaring dividends. If we are unable to raise additional funds when needed, we may be required to delay, limit, reduce, or terminate our product development or future commercialization efforts or grant rights to develop and market products or product candidates that we would otherwise prefer to develop and market ourselves.

Contractual Obligations and Other Commitments

We have certain contractual obligations under various license and collaboration agreements. Under these agreements, we will be required to make milestone payments upon successful completion and achievement of certain intellectual property, clinical, regulatory, and sales milestones, and we will be required to make milestone and royalty payments in connection with the sale of products developed under these agreements. In addition, under our co-development agreement, if Taiho generates sufficient data to support commercial purposes or a regulatory submission for new zipalertinib indications that it independently develops, half of Taiho’s independent development costs, subject to certain adjustments, will be deducted from future pre-tax profits related to potential U.S. sales of zipalertinib. As the achievement and timing of these future contractual obligations are not probable or estimable, such amounts have not been included in our consolidated balance sheets as of December 31, 2025 and 2024.

As of December 31, 2025, total future minimum lease payments were $3.1 million, with $1.0 million payable within 12 months. See Note 12 of our consolidated financial statements included in this Annual Report on Form 10-K for further detail on our lease obligations and the timing of expected future payments.

In addition, we enter into agreements in the normal course of business with CROs for clinical trials and with other vendors for preclinical studies, manufacturing services, and other services and products for operating purposes, which are generally cancelable upon written notice.

Critical Accounting Policies and Estimates

Our consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles ("GAAP"). The preparation of our consolidated financial statements and related disclosures requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, costs and expenses, and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in more detail in Note 2 of our consolidated financial statements included in this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Research and Development Contract Costs and Accruals

Research and development costs are expensed as incurred. We record accrued liabilities for estimated costs of research and development activities conducted by third-party service providers, which include the conduct of preclinical studies, clinical trials and contract manufacturing activities. We record the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and include these costs in accrued research and development liabilities in our consolidated balance sheets and within research and development expense in our consolidated statements of operations and comprehensive income (loss). These costs are a significant component of our research and development expenses.

We accrue for these costs based on factors such as estimates of the amount of work completed through discussions with internal personnel and external service providers as to the progress or stage of completion of the services and in accordance with agreements established with our third-party service providers for such services. We make significant judgments and estimates in determining the accrued research and development liabilities balance at each reporting period. As actual costs become known, we adjust our accrued estimates. Although we do not expect our estimates to be materially different from amounts actually incurred, the status and timing of services performed, the number of patients enrolled in clinical trials and the rate of patient enrollment may vary from our estimates and could result in us reporting amounts that are too high or too low in any particular period. Our accrued expenses are dependent, in part, upon the receipt of timely and accurate reporting from clinical research organizations and other third-party service providers. We record advance payments to service providers as prepaid assets, which are expensed as the contracted services are performed.

Equity-Based Compensation Expense

We estimate the fair value of stock options using the Black-Scholes option pricing model, which requires the input of objective and subjective assumptions. Certain assumptions used, including our expected stock price volatility, represent management’s estimates and involve inherent uncertainties and the application of management’s judgment. As a result, if factors change and management uses different assumptions, equity-based compensation expense could be materially different for future awards.

We do not have sufficient historical or implied volatility data for our common stock necessary to estimate expected volatility over a period of time commensurate with the expected term of our stock option awards. We use a blended rate to calculate expected volatility that combines our historical volatility with the historical volatilities of the stock prices of similar entities within our industry over a period of time commensurate with the expected term assumption.

Income Taxes

Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. A reduction in the carrying value of the deferred tax assets is required when it is not more likely than not that such deferred tax assets are not realizable. Judgment is required to if certain income tax positions are more likely than not of being sustained and may change from period to period when there is a change in judgment.

Recently Issued and Adopted Accounting Pronouncements

A description of recently issued and adopted accounting pronouncements that may potentially impact our financial position and results of operations is disclosed in Note 2 of our consolidated financial statements included in this Annual Report on Form 10-K.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

We are a smaller reporting company as defined by Item 10 of Regulation S-K and are not required to provide the information otherwise required under this Item.

Item 8. Financial Statements and Supplementary Data.

The financial statements required to be filed pursuant to this Item 8 are appended to this Annual Report on Form 10-K. An index of those financial statements is found in Item 15, Exhibits and Financial Statement Schedules, of this Annual Report on Form 10-K.

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.

There has been no change of accountants nor any disagreements with accountants on any matter of accounting principles or practices of financial disclosure required to be reported under this Item.

Item 9A. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

Based on an evaluation under the supervision and with the participation of our management, our principal executive officer and principal financial officer have concluded that our disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934 (as amended, the "Exchange Act") were effective as of December 31, 2025 to provide reasonable assurance that information required to be disclosed by us in reports that we file or submit under the Exchange Act is (i) recorded, processed, summarized, and reported within the time periods specified in the SEC rules and forms and (ii) accumulated and communicated to our management, including our principal executive officer and principal financial officer, as appropriate, to allow timely decisions regarding required disclosure.

Inherent Limitations on Internal Controls

Our internal control over financial reporting is designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP. The Company’s internal control over financial reporting includes those policies and procedures that:

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pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of assets;

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provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with GAAP, and that receipts and expenditures are being made only in accordance with the authorizations of management and directors; and

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provide reasonable assurance regarding the prevention or timely detection of unauthorized acquisition, use or disposition of assets that could have a material effect on our financial statements.

Our management, including the Chief Executive Officer and Chief Financial Officer, do not expect that our internal controls will prevent or detect all errors and all fraud. A control system, no matter how well designed and operated, can only provide reasonable, not absolute, assurance that the objectives of the control system are met. Further, the design of a control system reflects resource constraints, and the benefits of controls must be considered relative to their costs. Because there are inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that all control issues and instances of fraud, if any, within the Company have been detected. Also, any evaluation of the effectiveness of controls in future periods are subject to the risk that those internal controls may become inadequate because of changes in business conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Management’s Annual Report on Internal Control Over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over our financial reporting, as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act. Our management conducted an evaluation of the effectiveness of our internal control over financial reporting based on the framework provided in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on the results of its evaluation, management has concluded that our internal control over financial reporting was effective as of December 31, 2025 to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with GAAP.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) or 15(d)-15(f) under the Exchange Act) that occurred during the fiscal quarter ended December 31, 2025 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Item 9B. Other Information.

Rule 10b5-1 Trading Plans

During the fiscal quarter ended December 31, 2025, none of our directors and officers (as defined in Rule 16a-1(f) under the Exchange Act) adopted, modified, or terminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” as those terms are defined in Item 408(a) of Regulation S-K.

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections.

Not Applicable.

PART III

Item 10. Directors, Executive Officers and Corporate Governance.

Insider Trading Policies and Procedures

We have an insider trading policy which governs the purchase, sale and/or other dispositions of the Company’s securities by the Company’s directors, officers, employees, consultants, and other covered persons and is designed to promote compliance with insider trading laws, rules and regulations, and listing standards applicable to the Company. The Company’s Insider Trading Policy is included as an exhibit to this Annual Report on Form 10-K.

The other information required by this Item 10 will be included in our Definitive Proxy Statement to be filed with the Securities and Exchange Commission (the “SEC”), with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

Item 11. Executive Compensation.

The information required by this Item 11 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

The information required by this Item 12 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

The information required by this Item 13 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

Item 14. Principal Accountant Fees and Services.

The information required by this Item 14 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

PART IV

Item 15. Exhibits and Financial Statement Schedules.

(1)

For a list of the financial statements included herein, see Index to the Consolidated Financial Statements on page F-1 of this Annual Report on Form 10-K, incorporated into this Item by reference.

(2)

Financial statement schedules have been omitted because they are either not required or not applicable or the information is included in the consolidated financial statements or the notes thereto included in this Annual Report on Form 10-K.

(3)

The exhibits filed as part of this Annual Report on Form 10-K are set forth on the Exhibit Index immediately following our consolidated financial statements. The Exhibit Index is incorporated herein by reference.

Item 16. Form 10-K Summary.

None.

CULLINAN THERAPEUTICS, INC.

Index to Financial Statements

Page

Consolidated Balance Sheets F-3

Consolidated Statements of Operations and Comprehensive Income (Loss) F-4

Consolidated Statements of Stockholders' Equity F-5

Consolidated Statements of Cash Flows F-6

Notes to Consolidated Financial Statements F-7

F-1

Report of Independent Registered Public Accounting Firm

To the Stockholders and the Board of Directors

Cullinan Therapeutics, Inc.:

Opinion on the Consolidated Financial Statements

We have audited the accompanying consolidated balance sheets of Cullinan Therapeutics, Inc. and subsidiaries (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations and comprehensive income (loss), stockholders’ equity, and cash flows for the years then ended, and the related notes (collectively, the consolidated financial statements). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for the years then ended, in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on these consolidated financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

Critical audit matters are matters arising from the current period audit of the consolidated financial statements that were communicated or required to be communicated to the audit committee and that: (1) relate to accounts or disclosures that are material to the consolidated financial statements and (2) involved our especially challenging, subjective, or complex judgments. We determined that there are no critical audit matters.

/s/ KPMG LLP

We have served as the Company’s auditor since 2018.

Boston, Massachusetts

March 10, 2026

F-2

CULLINAN THERAPEUTICS, INC.

Consolidated Balance Sheets

(in thousands, except share amounts)

December 31,

Assets

Current assets:

Prepaid expenses and other current assets 8,860 15,691

Property and equipment, net 421 683

Operating lease right-of-use assets 2,630 1,667

Liabilities and Stockholders' Equity

Current liabilities:

Accrued expenses and other current liabilities 36,120 27,663

Operating lease liabilities, current 780 1,302

Long-term liabilities:

Operating lease liabilities, net of current portion 1,903 849

Commitments and contingencies (Note 11)

Stockholders' equity:

Accumulated other comprehensive gain (loss) 1,020 (133 )

Noncontrolling interests — —

Total liabilities and stockholders' equity $ 448,374 $ 621,824

See accompanying notes to the consolidated financial statements.

F-3

CULLINAN THERAPEUTICS, INC.

Consolidated Statements of Operations and Comprehensive Income (Loss)

(in thousands, except per share amounts)

Operating expenses:

Other income (expense):

Other income (expense), net (443 ) (199 )

Income tax expense — 117

Net loss attributable to noncontrolling interests — (192 )

Comprehensive income (loss):

Unrealized gain (loss) on investments 1,153 (4 )

Comprehensive loss attributable to noncontrolling interests — (192 )

Comprehensive loss attributable to Cullinan $ (218,726 ) $ (167,387 )

Basic and diluted net loss per share attributable to Cullinan:

Common stock $ (3.36 ) $ (2.78 )

See accompanying notes to the consolidated financial statements.

F-4

CULLINAN THERAPEUTICS, INC.

Consolidated Statements of STOCKHOLDERS’ EQUITY

(in thousands, except share amounts)

Shares Amount Shares Amount Capital Income (Loss) Deficit Subsidiaries Equity

Equity-based compensation — — — — 37,824 — — — 37,824

Acquisition of noncontrolling interests — — — — (4,448 ) — — — (4,448 )

Unrealized loss on investments — — — — — (4 ) — — (4 )

Equity-based compensation — — — — 36,040 — — — 36,040

Unrealized gain on investments — — — — — 1,153 — — 1,153

See accompanying notes to the consolidated financial statements.

F-5

CULLINAN THERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

Operating activities:

Adjustments to reconcile net loss to net cash used in operating activities:

Accretion on marketable securities (6,306 ) (15,469 )

Depreciation and amortization 311 306

Changes in operating assets and liabilities:

Prepaid expenses and other current assets 6,897 (2,472 )

Accrued expenses and other liabilities 8,026 2,895

Investing activities:

Purchase of property and equipment (49 ) —

Net cash provided by (used in) investing activities 179,989 (136,314 )

Financing activities:

Issuance of common stock under equity-based compensation plans 1,088 7,984

Acquisition of noncontrolling interests — (4,448 )

Net cash provided by financing activities 1,088 266,188

Net decrease in cash and cash equivalents 5,327 (15,429 )

Cash and cash equivalents at beginning of period 83,005 98,434

Cash and cash equivalents at end of period $ 88,332 $ 83,005

SUPPLEMENTAL NONCASH DISCLOSURE

Cash refunded for income taxes $ (2,970 ) $ (2,274 )

See accompanying notes to consolidated financial statements.

F-6

CULLINAN THERAPEUTICS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

(1)

Nature of Business and Basis of Presentation

Organization

Cullinan Therapeutics, Inc., together with its consolidated subsidiaries ("Cullinan" or "the Company"), is a clinical-stage biopharmaceutical company developing therapies for autoimmune diseases and cancer that was incorporated in September 2016 and has a principal place of business in Cambridge, Massachusetts. In April 2024, the Company changed its name from Cullinan Oncology, Inc. to Cullinan Therapeutics, Inc.

Liquidity

The Company has a history of significant operating losses and has had negative cash flows from operations since its inception and expects to continue to generate operating losses for the foreseeable future. Cullinan’s ultimate success depends on the outcome of its research and development activities as well as its ability to commercialize the Company’s product candidates. Cullinan is subject to a number of risks including, but not limited to, the need to obtain adequate additional funding for the ongoing and planned clinical development of its product candidates. Due to the numerous risks and uncertainties associated with pharmaceutical development, government regulation, potential commercialization, intellectual property, and our reliance on third parties the Company is unable to accurately predict the timing or amount of funds required to complete development of its product candidates, and costs could exceed Cullinan’s expectations for a number of reasons, including reasons beyond the Company’s control.

Since inception, Cullinan has funded its operations primarily through the sale of equity securities and from licensing or selling the rights to its product candidates. The Company expects that its cash, cash equivalents, and short-term investments of $377.9 million, and long-term investments and interest receivable of $61.1 million as of December 31, 2025, will be sufficient to fund its operating expenses and capital expenditure requirements through the next twelve months from the date of issuance of these consolidated financial statements.

Basis of Presentation

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

(2)

Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of Cullinan and consolidated subsidiaries. The Company considers its voting rights, effective economic control, or other control over an entity when evaluating whether to consolidate an entity for financial reporting.

Use of Estimates

The preparation of Cullinan’s consolidated financial statements and accompanying notes in conformity with U.S. GAAP requires the Company’s management to make estimates and judgments that affect the amounts reported in the financial statements. On an ongoing basis, Cullinan’s management evaluates its estimates, which include, but are not limited to, estimates related to prepaid and accrued research and development expenses, equity-based compensation, income taxes, and the fair value of royalty transfer agreements. Management's estimates could change period to period based on changes in facts and circumstances. The Company’s management bases its estimates on historical experience and on other relevant assumptions that are believed to be reasonable. Actual results may differ materially from these estimates.

Concentration of Risk

Cullinan had no significant concentration of credit risk as of December 31, 2025. Cash and cash equivalents are primarily maintained with three financial institutions in the U.S. as of December 31, 2025. Deposits at banks may exceed the federally insured limits. To date, the Company has not experienced any losses on such accounts. Under our investment policy, the Company limits amounts invested in such securities by investment type, credit rating, maturity, industry group and issuer. The goals of our investment policy are (i) safety and preservation of principal and diversification of risk and (ii) liquidity of investments sufficient to meet cash flow requirements.

F-7

Cullinan is subject to certain risks and uncertainties and believes that changes in any of the following areas could have a material adverse effect on future financial position or results of operations: ability to conduct and complete preclinical and clinical trials of our current and future product candidates; ability to obtain future financing; ability to build a successful pipeline of product candidates, including efficient expenditures of its resources; regulatory approval and market acceptance of, and reimbursement for, current and future product candidates; protection of Cullinan’s intellectual property, including litigation or claims against the Company based on intellectual property, patent, product, regulatory or other factors; performance of third-party clinical research organizations and manufacturers upon which the Company relies; and Cullinan’s ability to attract and retain employees necessary to support its growth.

The Company is dependent and expects to continue to be dependent on a small number of third-party manufacturers to supply drug product and drug substance for research and development activities in its programs. These programs could be adversely affected by a significant interruption in supply.

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less at the time of purchase to be cash equivalents. As of December 31, 2025 and 2024, cash equivalents consist of government-backed money market funds.

Investments

Cullinan generally holds investments in marketable securities. Investments not classified as cash equivalents with maturities of less than twelve months are classified as short-term investments in the consolidated balance sheets. Investments with maturities greater than twelve months for which the Company has the intent and ability to hold the investment for greater than twelve months are classified as long-term investments in the consolidated balance sheets.

The amortized cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in interest income. Dividends are also included in interest income. Interest receivable is included in prepaid expenses and other current assets on the consolidated balance sheets and represents accrued and unpaid interest on Cullinan's marketable securities.

The Company periodically reviews its investments for impairment based on a security-specific analysis as of each balance sheet date. If the fair value of a security is below its amortized cost, the Company first assesses whether it intends to sell the security or is more likely than not required to sell it before recovery of its amortized cost. If neither condition is met, the Company evaluates whether a portion of the decline is attributable to credit loss. Any credit-related impairment is recorded as an allowance for credit losses through earnings, with non-credit-related unrealized losses recorded in other comprehensive income (loss).

Fair Value of Financial Instruments

Cullinan has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. The three levels of the fair value hierarchy are described below:

Level 1—Unadjusted quoted prices for identical assets or liabilities in active markets that the Company has the ability to access;

Level 2—Quoted prices for similar assets and liabilities in active markets or other market-observable inputs such as interest rates, yield curves and foreign currency spot rates; and

Level 3—Pricing or valuations that require inputs that are both significant to the fair value measurement and unobservable.

There were no transfers of financial assets or liabilities measured at fair value between Level 1 and Level 2, and there were no Level 3 investments during 2025 or 2024.

Cullinan's financial assets recorded at fair value consist of investments. The fair value of the Company’s investments is primarily determined using market quotations or prices obtained from independent pricing sources.

Property and Equipment, net

Property and equipment is stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows:

Asset Class Estimated Useful Life

Office furniture and equipment 5 years

Leasehold improvements Shorter of the useful life of the asset or the lease term

F-8

Maintenance and repairs that do not improve or extend the life of the assets are expensed when incurred. Upon disposal or retirement of assets, the cost and accumulated depreciation and amortization are removed from the consolidated balance sheets and any resulting gain or loss is reflected in the consolidated statements of operations and comprehensive income (loss).

Leases

Cullinan determines if an arrangement is a lease at inception. A contract is or contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The Company classifies leases at the lease commencement date as operating or finance leases and records a right-of-use asset ("ROU") and a lease liability on the consolidated balance sheets for all leases with an initial lease term of greater than 12 months. Leases with an initial term of 12 months or less are not recorded in the balance sheet, and payments are recognized as expense on a straight-line basis over the lease term.

Cullinan enters into contracts that contain both lease and non-lease components. Non-lease components may include maintenance, utilities and other operating costs. The Company combines the lease and non-lease components of fixed costs in its lease arrangements as a single lease component. Variable costs, such as utilities or maintenance costs, are not included in the measurement of ROU assets and lease liabilities but rather are expensed when the event determining the amount of variable consideration to be paid occurs.

Operating lease assets and liabilities are recognized at the lease commencement date based on the present value of the lease payments over the lease term using the discount rate implicit in the lease. If the discount rate is not readily determinable, Cullinan utilizes an estimate of its incremental borrowing rate based upon the available information at the lease commencement date. Operating lease assets are further adjusted for prepaid or accrued lease payments. Operating lease payments are expensed using the straight-line method as an operating expense over the lease term. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that Cullinan will exercise that option.

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 may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated. Impairment charges are recognized at the amount by which the carrying amount of an asset exceeds the fair value of the asset. Assets to be disposed of are reported at the lower of the carrying amount or the fair value less costs to sell.

Noncontrolling Interests

Noncontrolling interests represent third-party interests in the Company’s subsidiaries. Cullinan determines the amount of the noncontrolling interests in the net assets of the Company’s subsidiaries at each balance sheet date using the hypothetical liquidation at book value ("HLBV") method. Under the HLBV method, the amounts reported as noncontrolling interests in the consolidated balance sheets represent the amounts third parties would hypothetically receive at each balance sheet date under the liquidation provisions of the subsidiaries, assuming the net assets of the subsidiaries were liquidated at their recorded amounts determined in accordance with U.S. GAAP and distributed to the owners of the subsidiaries. Net loss attributable to noncontrolling interests on the consolidated statements of operations and comprehensive income (loss) is determined as the difference in the noncontrolling interest in the consolidated balance sheets between the start and end of each reporting period, after taking into account any capital transactions between the subsidiaries and third parties.

Revenue Recognition

Revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which Cullinan expects to be entitled in exchange for these goods and services. To achieve this core principle, the Company applies the following five steps: 1) identify the customer contract; 2) identify the contract’s performance obligations; 3) determine the transaction price; 4) allocate the transaction price to the performance obligations; and 5) recognize revenue when or as a performance obligation is satisfied.

Licensing arrangements are analyzed to determine whether the promised goods or services, which could include licenses and research and development materials and services, are distinct or whether they must be accounted for as part of a combined performance obligation.

The transaction price is determined based on the consideration to which Cullinan will be entitled. The transaction price may include fixed amounts, variable amounts, or both. The Company reevaluates the probability of realizing such variable consideration and any related constraints at each reporting period. Cullinan includes variable consideration in the transaction price to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur.

F-9

The Company allocates the transaction price based on the estimated standalone selling price of the underlying performance obligations. Cullinan must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs to complete the respective performance obligation. Cullinan also utilizes judgment in assessing whether or not variable consideration is constrained or if it can be allocated specifically to one or more performance obligations in the arrangement.

When a performance obligation is satisfied, revenue is recognized for the amount of the transaction price allocated to that performance obligation on a relative standalone selling price basis, which excludes estimates of variable consideration that are constrained. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement.

For performance obligations consisting of licenses and other promises, Cullinan utilizes judgment to assess whether the combined performance obligation is satisfied over time or at a point in time and the recognition pattern for the portion of the transaction price allocated to the performance obligation.

Research and Development Expenses

Research and development costs are expensed as incurred. Research and development expenses consist primarily of employee compensation costs and amounts incurred with third parties for the provision of services for product candidate development, clinical and preclinical development and related supply and manufacturing costs, and regulatory compliance costs. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are received or services are performed. At the end of each reporting period, the Company conducts a thorough review of ongoing research and development activities to identify goods received or services rendered in order to establish an estimate of the associated costs incurred. The Company compares payments made to its vendors to its estimate of costs incurred to determine the resulting prepaid or accrual position. Significant judgments and estimates are made in determining the prepaid and accrued balances at the end of any reporting period. Such estimates are subject to change as additional information becomes available, and actual results could differ from the Company’s estimates.

Costs incurred to obtain licenses are recognized as research and development expense if the technology licensed has no alternative future use.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses in the consolidated statements of operations and comprehensive income (loss).

Equity-Based Compensation

Equity-based compensation is measured at the grant date for all equity-based awards using the fair value of the awards and is recognized as expense over the requisite service period, which is generally the vesting period. Forfeitures are recognized as they occur. Cullinan classifies equity-based compensation in its consolidated statements of operations and comprehensive income (loss) in the same manner in which the award recipient’s payroll costs or service payments are classified.

The fair value of service-based restricted stock units ("RSUs") is the closing market price of the Company's common stock on the grant date. The fair value of market-based RSUs is measured on the grant date using a Monte Carlo simulation model. Cullinan estimated the fair value of stock options using the Black-Scholes option pricing model. Both the Monte Carlo simulation model and the Black-Scholes option pricing model require the input of objective and subjective assumptions. Certain assumptions used, including the Company’s expected stock price volatility, involve inherent uncertainties and the application of management’s judgment. As a result, if factors change and management uses different assumptions, equity-based compensation expense could be materially different for future awards.

Income Taxes

Cullinan recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount of benefit that is greater than fifty percent likely to be realized upon settlement. Changes in measurement are reflected in the period in which the change in judgment occurs.

F-10

Net Loss per Share Attributable to Cullinan

Cullinan computes net loss per share attributable to Cullinan using the two-class method required for multiple classes of common stock. The Company has determined that the preferred stock does not have preferential rights over the Company’s common stock and, accordingly, is considered to be a second class of common stock for purposes of calculating net loss per share attributable to Cullinan. Basic net loss per share attributable to Cullinan is calculated by dividing the net loss attributable to Cullinan allocated to each share class by the weighted-average number of shares outstanding during the period for that share class. Diluted net loss per share attributable to Cullinan is determined by dividing net loss attributable to Cullinan allocated to each share class by the weighted-average number of shares outstanding during the period for that share class, adjusted for the dilutive effect of shares of common stock equivalents as determined using the treasury stock method for equity awards and the if-converted method for preferred stock.

Recently Adopted Accounting Pronouncements

In December 2023, the Financial Accounting Standards Board (the “FASB”) issued an accounting standards update to enhance transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. The main provisions in this update require companies to disclose, on an annual basis, specific categories in the rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. This update also requires companies to disclose, on an annual basis, the amount of income taxes paid, income (or loss) from continuing operations before income tax expense (or benefit), and income tax expense (or benefit) from continuing operations, disaggregated between federal, state and foreign jurisdictions. Cullinan adopted this standard on a retrospective basis effective January 1, 2025 for 2025 annual reporting and interim periods beginning in 2026.

Recently Issued Accounting Pronouncements

In November 2024, the FASB issued an accounting standards to improve disclosures regarding the types of expenses included in commonly presented expense captions, including disaggregating the amounts of employee compensation, depreciation and amortization included within each income statement expense caption. This standard is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. Cullinan will adopt this standard on January 1, 2027 for 2027 annual reporting and interim periods beginning in 2028 and is evaluating the impact of adopting this standard on its consolidated financial statements and disclosures.

(3)

Financial Instruments

Investments

Cullinan recognized its investments by security type at December 31, 2025 as follows (in thousands):

AmortizedCost GrossUnrealizedGains GrossUnrealizedLosses EstimatedFair Value

Short-term investments

Long-term investments

Asset-backed securities — — — —

F-11

Cullinan recognized its investments by security type at December 31, 2024 as follows (in thousands):

AmortizedCost GrossUnrealizedGains GrossUnrealizedLosses EstimatedFair Value

Short-term investments

Long-term investments

All of the Company's long-term investments as of each of December 31, 2025 and 2024 had maturities between one and two years from the respective balance sheet date. The Company did not recognize any credit loss relating to its investments during 2025 or 2024.

Fair Value of Financial Instruments

The following table sets forth the fair value of Cullinan’s financial assets that were measured at fair value on a recurring basis as of December 31, 2025 (in thousands):

Level 1 Level 2 Level 3 Total

Short-term investments

Long-term investments

Asset-backed securities — — — —

The following table sets forth the fair value of Cullinan’s financial assets that were measured at fair value on a recurring basis as of December 31, 2024 (in thousands):

Level 1 Level 2 Level 3 Total

Short-term investments

Long-term investments

As of December 31, 2025 and 2024, the fair values of cash and cash equivalents, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities approximated their carrying values due to the short-term nature of these instruments.

F-12

(4)

Property and Equipment, net

Property and equipment, net consisted of the following as of December 31, 2025 and 2024 (in thousands):

December 31,

Office furniture and equipment $ 814 $ 765

Total property and equipment, gross 1,390 1,341

Less: accumulated depreciation (969 ) (658 )

Total property and equipment, net $ 421 $ 683

Depreciation expense was $0.3 million in each of 2025 and 2024.

(5)

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following as of December 31, 2025 and 2024 (in thousands):

December 31,

Contracted research and development expenses $ 16,388 $ 10,297

Due to Taiho under collaboration agreement, net 8,784 5,994

(6)

License and Collaboration Agreements

Genrix License Agreement

In June 2025, the Company and Chongqing Genrix Biopharmaceutical Co., Ltd. (“Genrix”) entered into a license agreement (the “Genrix License Agreement”), pursuant to which Genrix granted Cullinan a global (excluding mainland China, Hong Kong, Macau and Taiwan), exclusive license to develop and commercialize velinotamig, a BCMAxCD3 bispecific T cell engager, in all fields of use.

Under the terms of the Genrix License Agreement, Cullinan paid Genrix an upfront license fee of $20.0 million. Genrix will be eligible to receive up to $292.0 million in milestone payments based on the achievement of certain clinical and regulatory milestones. Genrix is also eligible to receive up to an additional $400.0 million in net sales-based milestones as well as tiered royalties ranging from mid-single digit to mid-teens, as a percentage of net sales of licensed products.

Unless earlier terminated, the Genrix License Agreement will continue in effect on a country-by-country basis until the expiration of Cullinan’s royalty obligations in such country. The Genrix License Agreement may be terminated by either party for a material breach by the other party, subject to notice and cure provisions, or in the event of the other party’s insolvency. Additionally, subject to a notice period, Cullinan may terminate the Genrix License Agreement for convenience. In the Genrix License Agreement, each party made customary representations and warranties and agreed to customary covenants, including, without limitation, with respect to indemnification, for transactions of this type.

Cullinan evaluated the Genrix License Agreement and determined that the exclusive license to develop and commercialize velinotamig represented an asset acquisition of in-process research and development. The Company also determined that the asset had no alternative future use at the time of acquisition, and therefore, the upfront license fee of $20.0 million was recorded within research and development expenses in 2025.

Taiho Agreements

Cullinan has a co-development agreement with an affiliate of Taiho Pharmaceutical Co., Ltd ("Taiho"), pursuant to which the Company is collaborating to develop zipalertinib for the treatment of a genetically defined subset of patients with NSCLC, and Taiho will commercialize zipalertinib. For the agreed-upon indication, Cullinan and Taiho share development costs equally, and each party will receive 50% of any future pre-tax profits from potential U.S. sales of zipalertinib. For any additional indications that Taiho chooses to develop independently, Taiho will bear all development costs until they have sufficient data from such indication to support a commercial purpose or submission of zipalertinib for such indication. At such time, 50% of Taiho’s independent development costs, subject to certain adjustments, will be deducted from future pre-tax profits for potential U.S. sales of zipalertinib. In November 2025, Taiho independently initiated an ongoing global Phase 3 clinical trial evaluating zipalertinib in an additional indication.

F-13

The Company concluded that the co-development agreement with Taiho is a collaborative arrangement because Cullinan is an active participant in the development of zipalertinib, and in the oversight of commercialization for zipalertinib. Amounts due to or from Taiho for zipalertinib development activities after the execution of the co-development agreement are recorded within research and development expenses or general and administrative expenses based on the nature of the activity. The following table summarizes each party’s respective share of costs incurred and paid by the other party for zipalertinib development activities for 2025 and 2024 (in thousands):

Under a separate agreement, Cullinan is also eligible to receive up to $130.0 million from Taiho tied to epidermal growth factor receptor exon 20 non-small-cell lung cancer U.S. regulatory milestones. As of December 31, 2025, no milestone payments have been received under this agreement.

DKFZ/Tübingen License Agreement

The Company has exclusive worldwide rights to CLN-049, its bispecific T cell engager targeting FLT3 and CD3, pursuant to an exclusive license agreement (the "DKFZ/Tübingen License Agreement") with Deutsches Krebsforschungszentrum ("DKFZ"), Eberhard Karls University of Tübingen, Faculty of Medicine, and Universitätsmedizin Gesellschaft für Forschung und Entwicklung mbH, Tübingen. Pursuant to the DKFZ/Tübingen License Agreement, DKFZ and the University of Tübingen, collectively referred to as the Licensor, granted to Cullinan an exclusive worldwide, milestone- and royalty-bearing license under certain licensed patent rights, applications, technical information and know-how, with the right to grant sublicenses through multiple tiers to research, develop, commercialize or otherwise exploit licensed products within the field.

The Company shall pay certain non-refundable, non-creditable milestone payments to the Licensor upon the occurrence of certain clinical and regulatory events related to a licensed product. Each milestone payment is paid one time only up to a certain payment amount.

Furthermore, Cullinan is required to pay running low to mid-single digit royalty percentage on net sales of each licensed product on a country-by-country and product-by-product basis during the royalty term, subject to certain offsets or reductions. The aggregate, worldwide royalties due to Licensor for net sales of any licensed product in a calendar year shall not be reduced to an amount less than low to mid-single digit percentages. Such royalty obligations will expire on a country-by-country and product-by-product basis upon the later of (a) the expiration of the last valid claim of a patent which covers a product in such country and (b) a low double digit anniversary following the first commercial sale of a product in such country. Under certain conditions upon a first change in control in the Company's CLN-049 development subsidiary, Cullinan shall pay a non-refundable, non-creditable mid-single digit percent of sale proceeds, provided, however, that such payment shall not be required following consummation of an initial public offering of the Company's CLN-049 development subsidiary.

Either party may terminate the agreement upon a material breach by the other party or insolvency of the other party. Cullinan may terminate the DKFZ/Tübingen License Agreement for any or no reason after the first filing of an investigational new drug application or clinical trial agreement by providing prior written notice. Licensor may terminate the agreement by providing prior written notice, if the Company or any of its affiliates challenges the validity of certain patent rights. Unless earlier terminated, the DKFZ/Tübingen License Agreement continues perpetually. As of December 31, 2025, no milestone obligations have been incurred under the DKFZ/Tübingen License Agreement.

Adimab

Cullinan has a collaboration agreement with Adimab, LLC ("Adimab") (the "Adimab Collaboration Agreement"). Pursuant to the Adimab Collaboration Agreement, the Company selected a single-digit number of biological targets against which Adimab used its proprietary platform technology to discover and/or optimize antibodies, including antibody components that were used to generate CLN-978, based upon mutually agreed-upon research plans. Under the Adimab Collaboration Agreement, Cullinan has the ability to select additional biological targets against which Adimab will provide additional antibody discovery and optimization services for delivery of binders with a specified range of binding affinities.

During the research term and evaluation term for a given research program with Adimab, the Company has a non-exclusive worldwide license under Adimab’s technology to perform certain research activities and to evaluate the program antibodies to determine whether Cullinan wants to exercise its option to obtain a royalty-free, fully paid, non-exclusive license to exploit such antibodies and sublicense through multiple tiers (the "Adimab Option").

F-14

Under the Adimab Collaboration Agreement, Cullinan paid a one-time, non-creditable, non-refundable technology access fee. Cullinan is also required to pay an annual access fee and research funding fees, which are creditable against the annual access fee for Adimab’s performance of its’ research obligations under the Adimab Collaboration Agreement. Cullinan is also obligated to make certain research delivery, clinical and sales milestone payments to Adimab in an aggregate amount of up to $15.8 million for each product, on a product-by-product basis, subject to certain reductions and discounts. As of December 31, 2025, Cullinan has incurred and paid a cumulative $0.5 million of milestone obligations for CLN-978 under the Adimab Collaboration Agreement.

Cullinan is obligated to pay certain royalty payments on a product-by-product basis at a low single-digit percentage of annual aggregate worldwide net sales. Such royalty obligations will expire on a country-by-country and product-by-product basis upon the later of (a) a certain low double-digit number of years after the first commercial sale of such product in such country and (b) the expiration of the last issued and not expired, permanently revoked, or invalid claim within a program patent covering such product.

Cullinan may terminate the Adimab Collaboration Agreement at any time, for any reason, upon a specified period advance written notice. The term of the Adimab Collaboration Agreement expires upon the last research program’s evaluation term in the event no Adimab Option is exercised or in the event an Adimab Option is exercised, after the royalty term expires at the later of a specified period or invalid patent coverage of the relevant product.

During 2025 and 2024, Cullinan did not incur any milestone obligations under the Adimab Collaboration Agreement.

Massachusetts Institute of Technology

The Company had an exclusive patent license agreement (the "MIT License Agreement") for the technology underlying CLN-617 with MIT through its development subsidiary, Cullinan Amber Corp. ("Cullinan Amber"). Under the terms of the MIT License Agreement, Cullinan has incurred and paid $0.7 million of milestone obligations through December 31, 2025. In November 2025, after a review of the emerging clinical data in patients with advanced solid tumors, Cullinan decided not to pursue further development of CLN-617. In connection with the decision not to pursue further development of CLN-617, the Company notified MIT of its decision to terminate the MIT License Agreement. In connection with the termination of the MIT License Agreement, Cullinan returned the licensed patent rights for the technology underlying CLN-617 to MIT.

During 2025 and 2024, Cullinan did not incur any milestone obligations under the MIT License Agreement.

Harbour License Agreement

The Company and Harbour BioMed US Inc. (“Harbour”) were party to a license and collaboration agreement pursuant to which Harbour granted Cullinan an exclusive license for the development, manufacturing and commercialization of HBM7008 (CLN-418) in the U.S. In August 2024, following a review of the data from the Phase 1 clinical trial of CLN-418, the Company notified Harbour of its decision to terminate the license and collaboration agreement, effective November 2024. In connection with the termination, the Company discontinued development of CLN-418 and returned development and commercial rights for CLN-418 to Harbour.

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Stockholders' Equity

Common Stock

Each share of common stock entitles the holder to one vote and to receive dividends when and if declared by the board of directors of the Company.No dividends have been declared through December 31, 2025.

2024 Private Placement

In April 2024, Cullinan completed a private placement (the "2024 Private Placement") in which Cullinan issued approximately 14.4 million shares of its common stock and pre-funded warrants to purchase approximately 0.3 million additional shares of its common stock. Cullinan received net proceeds of $262.7 million from the 2024 Private Placement, after deducting offering costs of $17.3 million. Refer to the discussion under the heading “Warrants” below for further detail regarding the pre-funded warrants.

At-the-Market Equity Offering Program

Cullinan has an at-the-market equity offering program (the “ATM") through an agreement with Cowen and Company, LLC ("Cowen") pursuant to which the Company may offer and sell up to $125.0 million of its common stock from time to time through Cowen, acting as its sales agent. The Company made no sales under the ATM in 2025. Through December 31, 2025, the Company has sold approximately 3.3 million shares under the ATM and received net proceeds of $38.4 million after deducting commissions. As of December 31, 2025, Cullinan had $85.6 million in shares of its common stock remaining under the ATM.

F-15

Preferred Stock

Each share of preferred stock is convertible into ten shares of common stock at the option of the holder at any time, subject to certain limitations, including that the holder is prohibited from converting preferred stock into common stock if, as a result of such conversion, the holder, together with its affiliates, would beneficially own a number of shares of common stock more than 9.99% of the total common stock then issued and outstanding immediately following the conversion of such shares of preferred stock. Holders of the preferred stock are permitted to increase this percentage to an amount not to exceed 19.99% upon 60 days notice.

Shares of preferred stock generally have no voting rights, except as required by law and except that the consent of a majority of the holders of the outstanding preferred stock will be required to amend the terms of the preferred stock. In the event of the Company’s liquidation, dissolution or winding up, holders of preferred stock will participate pari passu with any distribution of proceeds to holders of common stock. Holders of preferred stock are entitled to receive when, as, and if dividends are declared and paid on the common stock, an equivalent dividend, calculated on an as-converted basis. Shares of preferred stock are otherwise not entitled to dividends.

The preferred stock ranks (i) senior to any class or series of capital stock of Cullinan created specifically ranking by its terms junior to the preferred stock; (ii) on parity with the common stock and any class or series of capital stock of the Company created specifically ranking by its terms on parity with the preferred stock; and (iii) junior to any class or series of capital stock of Cullinan created specifically ranking by its terms senior to any preferred stock, in each case, as to distributions of assets upon liquidation, dissolution or winding up of the Company, whether voluntarily or involuntarily.

The Company determined that the preferred stock should be classified as permanent equity.

Noncontrolling Interests in Subsidiaries

Certain of the Company's current and former clinical-stage product candidates are held through development subsidiaries in which the Company has controlling interests. The following table shows the Company’s ownership interest as of December 31, 2025 and 2024, respectively, in product candidates in which the Company has a controlling interest:

During 2024, Cullinan paid $4.4 million to acquire shares and options to purchase shares of its CLN-619 development subsidiary that were held by noncontrolling interests.

Warrants

In April 2025, all outstanding pre-funded warrants were exercised on a cashless basis in exchange for 0.3 million shares of common stock.

Cullinan determined that the pre-funded warrants should be equity-classified when they were issued. The Company also determined that the pre-funded warrants should be included in the weighted-average shares used in computing basic net loss per share attributable to common stockholders of Cullinan.

(8)

Equity-Based Compensation

The Company recorded equity-based compensation in the following expense categories in the consolidated statements of operations and comprehensive income (loss) in 2025 and 2024 (in thousands):

F-16

2021 Stock Option and Incentive Plan

Cullinan grants equity awards in the form of stock options and RSUs to its employees and non-employees directors, through the 2021 Stock Option and Incentive Plan (the "2021 Stock Plan"). Cullinan has also granted equity awards outside of the 2021 Stock Plan in the form of stock options as an inducement material to an individual's entering into employment with the Company. As of December 31, 2025, there were approximately 2.1 million shares remaining for future grants under the 2021 Stock Plan.

The 2021 Stock Plan provides that the number of shares reserved and available for issuance under the 2021 Stock Plan will automatically increase each January 1 by 5% of the outstanding number of shares of Cullinan’s common stock on the immediately preceding December 31 or such lesser number of shares as determined by Cullinan’s board of directors or compensation committee. On January 1, 2026, the total number of shares available for issuance under the 2021 Stock Plan increased by approximately 3.0 million shares under this provision.

The options granted have a ten-year term and were issued with an exercise price equal to the closing market price of Cullinan’s common stock on the grant date. For equity awards with service-based vesting conditions, Cullinan recognizes compensation expense over the vesting period, which is generally over a four-year period. For equity awards with a market-based vesting condition, the Company recognizes compensation expense over the requisite service period. The number of shares awarded, if any, when a market-based award vests will depend on the degree of achievement of the corporate stock price metrics within the performance period of the award.

Determining Fair Value of Options

The fair value of options is estimated using the Black-Scholes option pricing model, which takes into account inputs such as the exercise price, the value of the underlying common stock at the grant date, expected term, expected volatility, risk-free interest rate and dividend yield. The fair value of each grant of options during 2025 and 2024 were determined using the methods and assumptions discussed below:

•

The expected term of options is determined using the “simplified” method, as prescribed in the SEC Staff Accounting Bulletin (SAB) No. 107, whereby the expected life equals the arithmetic average of the vesting term and the original contractual term of the option due to Cullinan’s lack of sufficient historical data.

•

The risk-free interest rate is based on implied yields available from U.S. Treasury securities with a remaining term equal to the expected term assumed at the grant date.

•

The expected volatility used in the Black-Scholes option pricing model for new options was based on a blended rate that combines the Company’s historical volatility with the historical volatilities of the stock prices of similar entities within Cullinan’s industry over a period of time commensurate with the expected term assumption.

•

The estimated annual dividend yield was based on the Company’s expectation of not paying dividends on its common stock in the foreseeable future.

For 2025 and 2024, the weighted-average grant date fair value of the options granted were $6.01 and $12.28 per share, respectively. The grant date fair value was estimated at the time of grant using the Black-Scholes option-pricing model using the following weighted-average assumptions in 2025 and 2024:

Risk-free interest rate 4.3 % 4.2 %

Expected term (in years) 6.0 6.0

Expected volatility 69.8 % 70.3 %

Expected dividend yield 0.0 % 0.0 %

F-17

Stock Options

The following table summarizes 2025 stock option activity (options and aggregate intrinsic value in thousands):

As of December 31, 2025, there was $36.1 million in unrecognized compensation costs that are expected to be recognized over a remaining weighted-average period of 2.4 years.

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of Cullinan’s common stock for those options that had exercise prices lower than the fair value of the Company’s common stock at the measurement date. The total intrinsic value of options exercised in 2025 and 2024 was $0.1 million and $10.4 million, respectively.

RSUs

The following table summarizes the activity related to RSUs during 2025 (shares in thousands):

Number of Shares Weighted-Average Grant Date Fair Value

(1)

The number outstanding represents the number of shares issuable upon vesting of service-based and market-based RSUs, assuming the Company achieves its corporate stock price metrics at the target achievement level.

As of December 31, 2025, there was $15.5 million in unrecognized compensation cost related to RSUs expected to be recognized over a remaining weighted-average period of 2.6 years. The total fair value of RSUs that vested during 2025 and 2024 was $3.4 million and $2.9 million, respectively.

2021 Employee Stock Purchase Plan

The 2021 Employee Stock Purchase Plan (the "ESPP") authorizes the issuance of shares of common stock to participating eligible employees and provides for two six-month offering periods each year. As of December 31, 2025, there were approximately 2.1 million shares remaining for future purchases under the ESPP.

The ESPP provides that the number of shares reserved and available for issuance under the ESPP will automatically increase each January 1 by the lesser of 0.8 million shares of the Company's common stock, 1% of the outstanding number of shares of Cullinan’s common stock on the immediately preceding December 31, or such lesser number of shares as determined by the Company’s compensation committee. On January 1, 2026, the total number of shares available for issuance under the ESPP increased by approximately 0.6 million shares under this provision.

During each of 2025 and 2024, Cullinan issued less than 0.1 million shares of its common stock pursuant the ESPP.

F-18

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Royalty Transfer Agreements

The Company's CLN-049 development subsidiary is party to royalty transfer agreements with two charitable foundations. Under these royalty transfer agreements, the charitable foundations are collectively entitled to receive a low single digit royalty percentage of all global net sales of any products developed by the development subsidiary, subject to limitations after patent expirations and on intellectual property developed after a change of control. Cullinan has deemed these royalty transfer agreements to be freestanding financial instruments that should be accounted for at fair value. The Company concluded that these instruments had no value at the inception of the agreements.

Cullinan has not had any applicable net sales from its products and as a result, has not paid or incurred any royalties under these agreements as of December 31, 2025. Given the early-stage nature of the underlying technologies and inherent risks associated with obtaining regulatory approval and achieving commercialization, the Company ascribed no value to the royalty transfer agreements as of December 31, 2025 and 2024.

(10)

Income Taxes

Cullinan did not record income tax expense or benefit in 2025 due to its net loss before income taxes in the current year and expected losses in future years. During 2024, the Company recorded a current federal income tax expense of $0.1 million. The income tax expense recorded for 2024 was driven by the finalization of the federal research and development credits generated during 2023 that were carried back to tax year 2022. The Company’s net loss before income taxes consists solely of domestic losses in each of 2025 and 2024. As of December 31, 2024, Cullinan had recorded $3.0 million within prepaid expenses and other current assets on its consolidated balance sheets for the Company’s tentative refund from the carryback of 2023 federal research and development credits to tax year 2022.

During 2025, Cullinan was refunded $3.0 million for federal income taxes from the carryback of 2023 federal research and development credits to tax year 2022. During 2024, Cullinan paid $1.6 million for federal income taxes due to a refund payment from the Internal Revenue Service (the "IRS") that was in excess of the Company’s 2022 federal refund claim and was refunded $3.9 million for Massachusetts state income taxes from 2022 state refund claims.

A reconciliation of the Company’s statutory income tax rate to its effective income tax rate in 2025 and 2024 is as follows:

Amount Percentage Amount Percentage

Nontaxable or nondeductible items

Effective tax rate $ — — % $ 117 (0.07 )%

(1) Massachusetts makes up the majority (greater than 50 percent) of the State taxes, net of federal benefit category.

F-19

As of December 31, 2025 and 2024, the net deferred income tax asset balance related to the following (in thousands):

December 31,

Deferred tax assets:

Capitalized organizational and start-up expenses 83 101

Deferred tax liability

Depreciation and amortization 70 147

Net deferred tax asset $ — $ —

The Company's net operating loss ("NOL") and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service ("IRS") and state tax authorities. Under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, as well as similar state provisions, NOL and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant stockholders over a three-year period in excess of 50%. The rules generally operate by focusing on changes in ownership among stockholders considered by the rules as owning, directly or indirectly, 5% or more of the stock of a company and any change in ownership arising from new issuances of stock by the company.

As of December 31, 2025 and 2024, the Company had federal NOL carryforwards, of $312.6 million and $125.3 million, respectively, which may be available to offset future income tax liabilities. As of December 31, 2025, $311.2 million of Cullinan's federal NOL carryforwards can be carried forward indefinitely, and the remaining $1.4 million expires in 2037. As of December 31, 2025 and 2024, the Company had state NOL carryforwards of $317.7 million and $128.2 million, respectively, which may be available to offset future income tax liabilities. As of December 31, 2025, Cullinan's state NOL carryforwards begin to expire in 2031.

As of December 31, 2025 and 2024, the Company had federal research and development tax credit carryforwards of $8.7 million and $5.4 million, respectively. As of December 31, 2025, Cullinan’s federal research and development tax credit carryforwards begin to expire in 2036. As of each of December 31, 2025 and 2024, the Company had state research and development tax credit carryforwards of $2.7 million and $2.0 million, respectively. As of December 31, 2025, $0.3 million of Cullinan's state research and development tax credit carryforwards can be carried forward indefinitely, and the remaining $2.4 million expires beginning in 2036.

Cullinan has evaluated the positive and negative evidence bearing upon its ability to realize the deferred tax assets, which primarily consist of capitalized research and development costs, temporary differences on equity-based compensation, and NOL carryforwards. The Company has considered its history of cumulative net losses, estimated future taxable income and prudent and feasible tax planning strategies and has concluded that it is more likely than not that Cullinan will not realize the benefits of its deferred tax assets. As a result, as of December 31, 2025, the Company has maintained a full valuation allowance against its remaining net deferred tax assets.

Cullinan’s valuation allowance increased in 2025 primarily due to the valuation allowance on NOLs generated during the year and in 2024 primarily due to the valuation allowance on capitalized research and development costs and NOLs generated during the year. The following table summarizes activity in Cullinan’s valuation allowance during 2025 and 2024 (in thousands):

Valuation allowance at beginning of year $ 130,939 $ 87,371

Increases recorded to income tax provision 42,846 43,568

Increases (decreases) recorded to equity — —

F-20

The calculation of the Company’s tax liabilities involves dealing with uncertainties in the application of complex tax laws and regulations for both federal taxes and the states in which Cullinan operates or does business in.

The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, on the basis of the technical merits. Cullinan records uncertain tax positions as liabilities and adjusts these liabilities when its judgment changes as a result of the evaluation of new information not previously available. Due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from the Company’s current estimate of the unrecognized tax benefit liabilities. These differences will be reflected as increases or decreases to income tax expense in the period in which new information is available. As of December 31, 2025 and 2024, Cullinan has not recorded a liability for any uncertain tax positions in its consolidated financial statements.

The Company recognizes interest and penalties related to unrecognized tax benefits on the income tax expense line in the accompanying consolidated statements of operations and comprehensive income (loss). As of December 31, 2025 and 2024, no accrued interest or penalties are included in the consolidated balance sheets.

Cullinan files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions in the U.S. There are currently no pending tax examinations. Cullinan's federal and state income tax returns are generally subject to tax examinations for tax years 2022 and later. To the extent that the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the IRS and the state tax authorities to the extent utilized in a future period.

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Commitments and Contingencies

The Company enters into contracts in the normal course of business with contract research organizations, contract manufacturing organizations, and other third parties for preclinical research studies, clinical trials and testing and manufacturing services. These agreements generally include cancellation clauses.

Indemnification Agreements

In the ordinary course of business, Cullinan may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and executive officers that will require Cullinan, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in certain cases, unlimited. To date, Cullinan has not incurred any material costs as a result of such indemnifications. The Company is not aware of any indemnification arrangements that could have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of December 31, 2025 and 2024.

Legal Proceedings

Cullinan is not currently party to, or aware of, 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. Cullinan expenses as incurred the costs related to such legal proceedings.

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Leases

Cullinan has an operating lease for approximately 14,000 square feet of office space in a multi-tenant building in Cambridge, Massachusetts, which commenced in August 2022 and was scheduled to expire in July 2026. In October 2025, Cullinan extended its operating lease through September 2028. Cullinan determined that the lease extension constituted a modification of the existing lease, which required remeasurement of the lease liability and a corresponding adjustment to the right-of-use-asset. Lease expense consisted of operating lease costs of $1.2 million for each of 2025 and 2024.

The following table summarizes supplemental cash flow information for 2025 and 2024 (in thousands):

Cash paid for amounts included in measurement of lease liabilities:

Operating cash flows from operating leases $ 1,461 $ 1,738

ROU asset obtained in exchange for an operating lease liability $ 1,797 $ —

F-21

The following table summarizes Cullinan’s future minimum lease payments as of December 31, 2025 (in thousands):

Total future minimum lease payments 3,125

Less: imputed interest (442 )

Total lease liabilities at present value $ 2,683

The following table summarizes the weighted-average lease term and discount rate as of December 31, 2025 and 2024:

Weighted-average remaining lease term (in years) 2.8 1.6

Weighted-average discount rate 11.8 % 11.0 %

As Cullinan’s operating leases did not provide an implicit rate, the Company used its incremental borrowing rate based on the information available in determining the present value of lease payments. Cullinan’s incremental borrowing rate was based on the term of the lease, the economic environment and reflects the rate the Company would have had to pay to borrow on a secured basis.

(13)

Net Loss per Share Attributable to Cullinan

The Company computes net loss per share attributable to Cullinan for its common stock and preferred stock using the two-class method required for multiple classes of common stock. The two-class method is an earnings (loss) allocation method under which earnings (loss) per share is calculated for each class of common stock.

The following table sets forth the calculation of basic and diluted net loss per share attributable to Cullinan for 2025 and 2024 (in thousands, except per share data):

Common Stock Preferred Stock Common Stock Preferred Stock

Numerator:

Denominator:

Net loss per share attributable to Cullinan:

Cullinan used the treasury stock method for equity awards and the if converted method for preferred stock to determine the number of dilutive shares outstanding in each period. The following table sets forth potential common shares that were excluded from the computation of diluted net loss per share attributable to common stockholders of Cullinan for 2025 and 2024 because their effect would have been anti-dilutive (in thousands):

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Segment Reporting

The Company operates and manages the business as one reporting and one operating segment, which is the business of developing immunology and oncology therapies. Cullinan has determined that its Chief Executive Officer is the chief operating decision maker ("CODM"). Cullinan’s CODM reviews financial information on an aggregate basis and uses net loss attributable to Cullinan as presented in the consolidated statement of operations and comprehensive income (loss) for purposes of allocating resources and evaluating financial performance.

CGEM US Equity

CGEM · 10-K · period ended 2025-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Item 8. Financial Statements and Supplementary Data.

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.

Item 9A. Controls and Procedures.

Item 9B. Other Information.

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections.

Item 10. Directors, Executive Officers and Corporate Governance.

Item 11. Executive Compensation.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

Item 14. Principal Accountant Fees and Services.

Item 15. Exhibits and Financial Statement Schedules.

Item 16. Form 10-K Summary.

CGEM US Equity☆

CGEM · 10-K · period ended 2025-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Item 8. Financial Statements and Supplementary Data.

Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.

Item 9A. Controls and Procedures.

Item 9B. Other Information.

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections.

Item 10. Directors, Executive Officers and Corporate Governance.

Item 11. Executive Compensation.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

Item 14. Principal Accountant Fees and Services.

Item 15. Exhibits and Financial Statement Schedules.

Item 16. Form 10-K Summary.

CGEM US Equity