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

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our consolidated financial statements and related notes thereto and other financial information included elsewhere in this Annual Report. In addition to historical information, some of the information contained in the following discussion and analysis contains forward-looking statements that involve risks, uncertainties and assumptions. You should review the “Risk Factors” section of this Annual Report on Form 10-K for a discussion of important factors that could cause our actual results to differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

Overview

We are a late clinical-stage biotechnology company pioneering cell therapy for the treatment of autoimmune diseases. We leverage our proprietary technology and manufacturing platform to introduce mRNA into cells to provide a therapeutic effect to patients suffering from a variety of autoimmune conditions. Unlike DNA, mRNA degrades naturally over time without integrating into the cell’s genetic material. Our cell therapies are designed to be dosed repeatedly like conventional drugs, administered in an outpatient setting, and given without pre-treatment chemotherapy, which is required with many conventional cell therapies.

Table of Contents

Merger

On November 13, 2023, the Company (formerly known as Selecta) merged with the private Delaware corporation which, immediately prior to the Merger, was known as Cartesian Therapeutics, Inc., in accordance with the terms of the Merger Agreement, by and among Selecta, First Merger Sub, Second Merger Sub, and Old Cartesian. Pursuant to the Merger Agreement, First Merger Sub merged with and into Old Cartesian, pursuant to which Old Cartesian was the surviving corporation and became a wholly owned subsidiary of Selecta. Immediately following the First Merger, Old Cartesian merged with and into Second Merger Sub, pursuant to which Second Merger Sub was the surviving entity. In connection with the Second Merger, Old Cartesian changed its name to Cartesian Bio, LLC. In connection with the Merger and pursuant to the Merger Agreement, the Company changed its corporate name to Cartesian Therapeutics, Inc. See Note 4, “Merger” to the consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 for more information regarding the Merger.

Financial Operations

To date, we have financed our operations primarily through public offerings and private placements of our securities, funding received from research grants, collaboration and license arrangements and a credit facility. We do not have any products approved for sale and have not generated any product sales.

We incurred a net loss of $130.3 million and $77.4 million for the years ended December 31, 2025 and 2024, respectively. As of December 31, 2025, we had an accumulated deficit of $822.4 million. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we:

•continue to advance Descartes-08 for MG through Phase 3 development;

•advance Descartes-08 for myositis into Phase 2 development;

•continue to develop our preclinical and clinical-stage product candidates;

•seek regulatory approvals for any product candidates that successfully complete clinical trials;

•maintain, expand and protect our intellectual property portfolio, including through licensing arrangements;

•hire additional staff, including clinical, scientific and management personnel; and

•incur additional costs associated with continuing to operate as a public company.

Until we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, and license and collaboration agreements. We may be unable to raise capital when needed or on reasonable terms, if at all, which would force us to delay, limit, reduce or terminate our product development or future commercialization efforts. We will need to generate significant revenues to achieve profitability, and we may never do so.

Concurrently with the closing of the Merger, we entered into a securities purchase agreement, or the 2023 Securities Purchase Agreement, pursuant to which we agreed to issue 149,330.115 shares of Series A Preferred Stock, in exchange for aggregate gross proceeds of $60.25 million, or the 2023 Private Placement. We granted customary registration rights to investors in connection with the 2023 Private Placement.

We believe that our existing cash, cash equivalents, and restricted cash as of December 31, 2025 will enable us to fund our operating expenses and capital expenditure requirements for at least the next 12 months. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect.

The consolidated financial information presented below includes the accounts of Cartesian Therapeutics, Inc. and our wholly owned subsidiaries, Selecta (RUS) LLC, a Russian limited liability company, or Selecta (RUS), Selecta Biosciences Security Corporation, a Massachusetts securities corporation which was dissolved in December 2024, and Cartesian Bio, LLC, a Delaware limited liability company, which is a variable interest entity for which we are the primary beneficiary. All intercompany accounts and transactions have been eliminated.

Components of our Results of Operations

Collaboration and license revenue

To date, we have not generated any revenue from product sales. Our revenue consists primarily of collaboration and license revenue, which includes amounts recognized related to upfront and milestone payments for research and development funding under collaboration and license agreements. We expect that any revenue we generate will fluctuate from quarter to quarter

Table of Contents

because of the timing and amounts of fees, research and development reimbursements and other payments from collaborators. We do not expect to generate revenue from product sales for at least the next several years. If we or our collaborators fail to complete the development of our product candidates in a timely manner or fail to obtain regulatory approval as needed, our ability to generate future revenue will be harmed, and will affect the results of our operations and financial position. For further descriptions of the agreements underlying our collaboration and license revenue, see Notes 2, “Summary of Significant Accounting Policies” and 15, “Collaboration and License Agreements” to our consolidated financial statements included elsewhere in this Annual Report.

Grant revenue

We generate grant revenue, which consists of funding received to perform specific research and development services under grant arrangements.

Research and development expenses

Our research and development expenses consist of internal and external research and development costs, which primarily include fees paid to contract research organizations, internal manufacturing- and quality-related expenses, process development costs, internal research and development expenses, as well as fees paid to contract manufacturing organizations. These costs are primarily associated with compensation expenses for our research and development employees, capital equipment and supplies for our process development and manufacturing process, and other related expenses. Our internal research and development employees as well as our indirect costs are shared across multiple development programs and are not solely dedicated to individual programs.

We expense research and development costs as incurred. Conducting a significant amount of research and development is central to our business model. Product candidates in clinical development generally have higher development costs than those in earlier stages of development, primarily due to the size, duration and cost of clinical trials. The successful development of our clinical and preclinical product candidates is highly uncertain. Clinical development timelines, the probability of success and development costs can differ materially from our expectations. For example, if the FDA or another regulatory authority were to require us to conduct clinical trials beyond those which we currently expect will be required for the completion of clinical development of a product candidate, or if we experience significant delays in enrollment in any of our clinical trials, we could be required to expend significant additional financial resources and time to complete any clinical development.

General and administrative expenses

General and administrative expenses consist primarily of salaries and related benefits, including stock-based compensation, related to our executive, finance, business development and support functions. Other general and administrative expenses include facility-related costs not otherwise allocated to research and development expenses, travel expenses for our general and administrative personnel and professional fees for auditing, tax and corporate legal services, including intellectual property-related legal services.

Impairment of indefinite-lived intangible and long-lived assets

Impairment of indefinite-lived intangible and long-lived assets consists of impairment charges on our intangible and long-lived assets.

Interest income

Interest income consists primarily of income earned on our cash, cash equivalents and marketable securities.

Gain on change in fair value of warrant liabilities

Common warrants classified as liabilities are remeasured quarterly at fair value with the change in fair value recognized as a component of earnings.

Loss on change in fair value of contingent value right liability

The contingent value right liability is remeasured quarterly at fair value with the change in fair value recognized as a component of earnings.

Loss on change in fair value of forward contract liabilities

The forward contract liabilities associated with the delayed issuance of the Series A Preferred Stock related to the Merger and 2023 Private Placement were remeasured upon settlement at fair value with the change in fair value recognized as a

Table of Contents

component of earnings. The Series A Preferred Stock forward contract liability was settled during the year ended December 31, 2024

Other (expense) income, net

Other (expense) income, net consists of non-operating income and non-operating expenses, including impairment charge on investment.

Income taxes

We provide deferred tax assets and liabilities for the expected future tax consequences of temporary differences between our financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. A valuation allowance is provided to reduce the deferred tax assets to the amount that will more-likely-than-not be realized.

We determine whether it is more likely than not that a tax position will be sustained upon examination. If it is not more-likely-than-not that a position will be sustained, none of the benefit attributable to the position is recognized. The tax benefit to be recognized for any tax position that meets the more-likely-than-not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. We account for interest and penalties related to uncertain tax positions as part of its provision for income taxes. To date,we have not incurred interest and penalties related to uncertain tax positions.

Table of Contents

Results of Operations

Comparison of the Years Ended December 31, 2025 and 2024

Year Ended December 31, Increase (Decrease)

(in thousands, except percentages)

Revenues:

Operating expenses:

Other income (expense):

Gain on change in fair value of warrant liabilities 3,695 2,558 1,137 44 %

NM - Not meaningful

Collaboration and license revenue

During the year ended December 31, 2025, we recognized $0.4 million of collaboration and license revenue, compared to $38.3 million for the year ended December 31, 2024, a decrease of $37.9 million. The decrease was primarily due to revenue recognized under the Sobi License in the prior year, resulting from the $30.0 million unconstrained development milestone, coupled with recognition of the remaining deferred revenue under the License and Development Agreement, or the Astellas Agreement, with Audentes Therapeutics, Inc., or Astellas, upon notice of termination during the year ended December 31, 2024.

Grant revenue

During the year ended December 31, 2025, we recognized $2.4 million of grant revenue, compared to $0.6 million for the year ended December 31, 2024, an increase of $1.8 million. The increase was primarily due to increased expenses reimbursable under the grant from the National Institute of Neurological Disorders and Stroke of the National Institutes of Health incurred during the year ended December 31, 2025, for which we received funding approval during the year ended December 31, 2024.

Table of Contents

Research and development expenses

The following is a comparison of research and development expenses for the years ended December 31, 2025 and 2024 (in thousands, except percentages):

Year Ended December 31, Increase (Decrease)

Research and development stock-based compensation expense 4,772 3,217 1,555 48 %

NM - Not meaningful

For the year ended December 31, 2025, our research and development expenses were $58.0 million, compared to $45.1 million for the year ended December 31, 2024, an increase of $12.9 million. The increase was primarily due to an increase in expenses for the development of Descartes-08 for MG, primarily related to the expenses for the ongoing Phase 3 AURORA trial, an increase in our research and development employee expenses and stock-based compensation expense due to headcount growth and manufacturing operations expenses. These increases were partially offset by a decrease in expenses for legacy Selecta programs, primarily related to decreased expenses for Xork as a result of the termination of the Astellas Agreement in the year ended December 31, 2024 and a decrease in facilities and other expense, primarily driven by the move of costs associated with our leased office and laboratory space at 65 Grove Street, Watertown, Massachusetts moved to general and administrative expenses for the year ended December 31, 2025.

General and administrative expenses

For the year ended December 31, 2025, our general and administrative expenses were $31.5 million, compared to $30.1 million for the year ended December 31, 2024, an increase of $1.4 million. The increase was primarily due to an increase in facility and office costs, primarily as the result of the move of costs associated with our leased office and laboratory space at 65 Grove Street, Watertown, Massachusetts from research and development costs to general and administrative expenses, coupled with an increase in stock-based compensation, primarily driven by executive awards, and an increase in consulting expenses. These increases were partially offset by a decrease in professional fees, driven primarily by lower legal and audit fees, coupled with decreases in patent costs due to a smaller body of intellectual property work, and a decrease in salaries and benefits, driven by the retention bonus expense in the prior year.

Impairment of indefinite-lived intangible and long-lived assets

During the year ended December 31, 2025, we recorded a non-cash impairment charge of $56.7 million related to our in-process research and development, or IPR&D, asset related to Descartes-08 for SLE. See Note 3, “Goodwill and Indefinite-Lived Intangible Assets” for more information. During the year ended December 31, 2024, we recorded an impairment charge to our long-lived assets of $7.6 million after evaluating the right-of-use assets and related furniture and fixtures upon our decision to cease use of our office and laboratory space at 65 Grove Street, Watertown, Massachusetts.

Interest income

Interest income for the year ended December 31, 2025 was $6.6 million, compared to $7.4 million for the year ended December 31, 2024, a decrease of $0.8 million. The decrease in interest income was due to lower investment balances and lower interest rates.

Gain on change in fair value of warrant liabilities

For the year ended December 31, 2025, we recognized $3.7 million gain on the change in the fair value of warrant liabilities, compared to $2.6 million gain for the year ended December 31, 2024, an increase of $1.1 million. Fair value of warrant liabilities was determined utilizing the Black-Scholes valuation methodology. The decrease in warrant value was primarily driven by a decrease in the per-share price of our common stock and the passage of time.

Table of Contents

Loss on change in fair value of contingent value right liability

For the year ended December 31, 2025, we recognized a $4.4 million loss on the change in the fair value of contingent value right liability, compared to a loss of $36.9 million for the year ended December 31, 2024, a decrease of $32.5 million. The fair values of the contingent value right liability as of December 31, 2025 and 2024 were determined utilizing a Monte Carlo simulation model. The increase in the fair value of the contingent value right liability was primarily due to the passage of time, partially offset by changes in the anticipated amount and timing of future payments.

Loss on change in fair value of forward contract liabilities

For the year ended December 31, 2024, we recognized $6.9 million loss on the change in fair value of Series A Preferred Stock forward contract liabilities. The Series A Preferred Stock forward contract liability was settled during the year ended December 31, 2024.

Other (expense) income, net

During the year ended December 31, 2025, we recognized other expense, net of $2.0 million, compared to $0.6 million of other income, net for the year ended December 31, 2024, a change of $2.6 million. The change was primarily driven by a loss on impairment of an investment during the year ended December 31, 2025, coupled with sublease income in the year ended December 31, 2024. The terms of our subleases expired during the year ended December 31, 2024.

Income taxes

During the year ended December 31, 2025, we recognized a $9.2 million tax benefit primarily related to impairment of IPR&D during the year and corresponding deferred tax liability. During the year ended December 31, 2024, we recognized a deferred tax expense of $0.3 million relating to a change in state tax rate applied to the indefinite deferred tax liability.

Liquidity and Capital Resources

Except for net income for the year ended December 31, 2022, we have incurred recurring net losses since our inception. We expect that we will continue to incur losses and that such losses will increase for the foreseeable future. We expect that our research and development and general and administrative expenses will continue to increase and, as a result, we will need additional capital to fund our operations, which we may raise through a combination of equity offerings, debt financings, third-party funding, potential royalty and/or milestone monetization transactions and other collaborations and strategic alliances.

Our cash, cash equivalents, and restricted cash were $126.9 million as of December 31, 2025, of which $1.7 million was restricted cash related to lease commitments.

In addition to our existing cash equivalents, we from time to time have received and may receive in the future research and development funding pursuant to our collaboration and license agreements. Currently, funding from payments under our collaboration agreements represent our only source of committed external funds.

The liability associated with the contingent value rights agreement, or CVR Agreement, entered into on December 6, 2023, will be settled solely through cash flow received under the Sobi License and any other Gross Proceeds (as such term is defined in the CVR Agreement) net of certain agreed deductions. Under the CVR Agreement, 100% of all milestone payments, royalties, and other amounts paid to us or our controlled entities under the Sobi License, and any other Gross Proceeds, in each case net of certain agreed deductions, will be distributed to holders of the CVRs. There is no contractual obligation for us to fund any amount related to the CVR liability.

Collaboration and License Agreements

In-licenses

In September 2023, we entered into the Biogen Agreement with Biogen to research, develop, make, use, offer, sell and import products or processes containing or using an engineering T-cell modified with an mRNA comprising, or encoding a protein comprising, certain sequences licensed under the Biogen Agreement for the prevention, treatment, palliation and management of autoimmune diseases and disorders, excluding cancers, neoplastic disorders, and paraneoplastic disorders. We are not obligated to pay Biogen any expenses, fees, or royalties. For further description of the Biogen Agreement, see Note 15, “Collaboration and License Agreements” to our consolidated financial statements included elsewhere in this Annual Report.

Effective September 2019, we entered into the NCI Agreement with NCI. Under the NCI Agreement, we were granted a license under certain NCI patents and patent applications designated in the agreement, to make, use, sell, offer and import products and processes within the scope of the patents and applications licensed under the NCI Agreement when developing and manufacturing anti-BCMA CAR-T cell products for the treatment of MG, pemphigus vulgaris, and immune

Table of Contents

thrombocytopenic purpura according to methods designated in the NCI Agreement. In connection with our entry into the NCI Agreement, we paid to NCI a one-time $0.1 million license royalty payment. Under the NCI Agreement, we are further required to pay NCI a low five-digit annual royalty. We must also pay earned royalties on net sales in a low single-digit percentage and pay up to $0.8 million in benchmark royalties upon our achievement of designated benchmarks that are based on the commercial development plan agreed between the parties. For further description of the NCI Agreement, see Note 15, “Collaboration and License Agreements” to our consolidated financial statements included elsewhere in this Annual Report.

In October 2021, we entered into an Exclusive License Agreement with Genovis AB (publ.), or Genovis, or the Genovis Agreement, and paid Genovis a $4.0 million one-time upfront payment. In February 2023, as a result of the sublicense of Xork, a bacterial IgG protease, to Astellas, we made a $4.0 million payment to Genovis. The Genovis Agreement was terminated effective September 13, 2024. For further description of the Genovis Agreement, see Note 15, “Collaboration and License Agreements” to our consolidated financial statements included elsewhere in this Annual Report.

Out-licenses

In January 2023, we entered into the Astellas Agreement with Astellas. Under this agreement, Astellas obtained the sole and exclusive right to commercialize Xork for use in Pompe disease in combination with an Astellas gene therapy investigational or authorized product, with a current focus on AT845. In connection with entry into this agreement, we received a $10.0 million upfront payment and are eligible to receive $340.0 million for certain additional development and commercial milestones plus royalties on any potential commercial sales where Xork is used as a pre-treatment for AT845. As a result of the sublicense of Xork to Astellas, we made a $4.0 million payment to Genovis in February 2023. The Astellas Agreement was terminated effective June 6, 2024. For further description of the Astellas Agreement, see Note 13, “Revenue Arrangements” to our consolidated financial statements included elsewhere in this Annual Report. Amounts paid and remaining obligations with regard to the Xork product candidate not reimbursed by Astellas through the Astellas Agreement were subject to potential reimbursement through deductions to CVR distributions as described in Note 6, “Fair Value Measurements” to our consolidated financial statements included elsewhere in this Annual Report.

In June 2020, we entered into the Sobi License. Sobi paid us a one-time, upfront payment of $75.0 million, and upon the closing of a private placement of our common stock to Sobi at a price of $138.468 per share, we received an additional $25.0 million from Sobi. We are eligible to receive $630.0 million in milestone payments upon the achievement of various development and regulatory milestones and sales thresholds for annual net sales of NASP, and tiered royalty payments ranging from the low double digits on the lowest sales tier to the high teens on the highest sales tier. Sobi has agreed to fund the Phase 3 clinical program of NASP, which commenced in September 2020. In July 2022, we received $10.0 million for the completion of the enrollment of the DISSOLVE II trial. In July 2024, we received $30.0 million for the milestone associated with the initiation of a rolling biologics license application to the FDA for NASP for the potential treatment of chronic refractory gout by Sobi. Proceeds from milestone payments and royalties on sales of NASP, if any, are required to be distributed, net of certain agreed deductions, to holders of the CVRs. For further description of the Sobi License, see Note 13, “Revenue Arrangements” to our consolidated financial statements included elsewhere in this Annual Report.

Financings

On November 13, 2023, we entered into the 2023 Securities Purchase Agreement with (i) Timothy A. Springer, Ph.D., a member of our Board of Directors; (ii) TAS Partners LLC, an affiliate of Dr. Springer, and (iii) Seven One Eight Three Four Irrevocable Trust, a trust associated with Murat Kalayoglu, M.D., Ph.D., a co-founder and the former chief executive officer of Old Cartesian, who joined our Board of Directors effective immediately after the effective time of the Merger, providing for the 2023 Private Placement. In the 2023 Private Placement, we issued and sold an aggregate of 149,330.115 shares of Series A Preferred Stock for an aggregate purchase price of $60.25 million, of which 50,189.789 shares of Series A Preferred Stock were issued and sold in the year ended December 31, 2023 for gross proceeds of $20.25 million, and 99,140.326 shares of Series A Preferred Stock were issued and sold during the year ended December 31, 2024 for gross proceeds of $40.0 million.

On July 2, 2024, we entered into a securities purchase agreement, or the 2024 Securities Purchase Agreement, for a private investment in public equity financing, or the 2024 Private Placement, which provided for the issuance of 3,563,247 shares of common stock and 2,937,903 shares of Series B Preferred Stock, each at a purchase price of $20.00 per share. The 2024 Private Placement resulted in gross proceeds of approximately $130.0 million before deducting placement agent fees and other offering expenses. We granted customary registration rights to investors in connection with the 2024 Private Placement.

On December 13, 2024, we and Leerink Partners entered into a Sales Agreement, or the Sales Agreement. Under the Sales Agreement, we may issue and sell shares of our common stock, from time to time, through Leerink Partners for aggregate gross sales proceeds of up to $100.0 million. During the years ended December 31, 2025 and 2024, we sold no shares of our common stock pursuant to the Sales Agreement.

Table of Contents

Future funding requirements

As of the date of this Annual Report, we have not generated any revenue from product sales. We do not know when, or if, we will generate revenue from product sales. We will not generate significant revenue from product sales unless and until we obtain regulatory approval and commercialize one of our current or future product candidates. Our primary uses of capital are, and we expect will continue to be, compensation and related expenses, third-party clinical research and development services, laboratory and related supplies, clinical costs, legal and other regulatory expenses, milestone and royalty payments for in-licenses, and general overhead costs. We expect that we will continue to generate losses for the foreseeable future, and we expect the losses to increase as we continue the development of, and seek regulatory approvals for, our product candidates, and begin to commercialize any approved products. We are subject to risks in the development of our products, and we may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. We expect that we will need substantial additional funding to support our continuing operations.

As of December 31, 2025, we had an accumulated deficit of $822.4 million. We anticipate operating losses to continue for the foreseeable future due to, among other things, costs related to research, development of our product candidates, conducting preclinical studies and clinical trials, and our administrative organization. We will require substantial additional financing to fund our operations and to continue to execute our strategy, and we will pursue a range of options to secure additional capital.

We regularly evaluate various potential sources of additional funding such as strategic collaborations, license agreements, debt issuance, potential royalty and/or milestone monetization transactions and the issuance of equity instruments to fund our operations. If we raise additional funds through strategic collaborations and alliances, which may include existing collaboration partners, we may have to relinquish valuable rights to our technologies or product candidates, or grant licenses on terms that are not favorable to us. To the extent that we raise additional capital through the sale of equity instruments, the ownership interest of our existing stockholders will be diluted, and other preferences may be necessary that adversely affect the rights of existing stockholders.

We believe that our existing cash, cash equivalents, and restricted cash as of December 31, 2025 will enable us to fund our operating expenses and capital expenditure requirements for at least the next 12 months. We may pursue additional cash resources through public or private equity or debt financings, by establishing collaborations with other companies or through the monetization of potential royalty and/or milestone payments pursuant to our existing collaboration and license arrangements. Management’s expectations with respect to our ability to fund current and long-term planned operations are based on estimates that are subject to risks and uncertainties. If actual results are different from management’s estimates, we may need to seek additional strategic or financing opportunities sooner than would otherwise be expected. However, there is no guarantee that any of these strategic or financing opportunities will be executed on favorable terms, and some could be dilutive to existing stockholders. If we are unable to obtain additional funding on a timely basis, we may be forced to significantly curtail, delay, or discontinue one or more of our planned research or development programs or be unable to expand our operations, meet long-term obligations or otherwise capitalize on our commercialization of our product candidates.

Our future capital requirements will depend on many factors, including:

•the scope, progress, results and costs of our clinical trials, preclinical development, manufacturing, laboratory testing and logistics;

•the number of product candidates that we pursue and the speed with which we pursue development;

•our headcount growth and associated costs;

•the costs, timing and outcome of regulatory review of our product candidates;

•the costs and timing of future commercialization activities, including manufacturing, marketing, sales and distribution, for any of our product candidates for which we receive marketing approval;

•the revenue, if any, from commercial sales of our product candidates for which we receive marketing approval;

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

•the effect of competing technological and market developments; and

•the extent to which we acquire or invest in businesses, products and technologies, including entering into licensing or collaboration arrangements for product candidates.

Table of Contents

Cash Requirements due to Contractual Obligations and Other Commitments

We are under agreement to lease approximately 32,294 square feet of laboratory and office space in Watertown, Massachusetts through May 2028. Remaining lease payments from December 31, 2025 through the end of the lease term total approximately $6.8 million. Payments made and remaining obligations on this lease liability were subject to potential reimbursement through deductions to CVR distributions as described in Note 6 “Fair Value Measurements” to our consolidated financial statements included elsewhere in this Annual Report and were reimbursed in the March 2025 CVR distribution.

In November 2023, in connection with the Merger, we acquired two leases for office and laboratory space in Gaithersburg, Maryland, which expire in January 2027. Annualized rent is approximately $0.3 million and remaining lease payments from December 31, 2025 through the end of the lease term total approximately $0.4 million.

In February 2024, we entered into an agreement to lease approximately 19,199 square feet of integrated manufacturing and office space in Frederick, Maryland. In May 2024, we entered into an amendment to lease an additional approximately 7,842 square feet at the same site. In August 2024, we entered into a second amendment to lease an additional approximately 2,009 square feet at the same site. In March 2025, we entered into a third amendment to lease an additional approximately 6,439 square feet at the same site. The leases expire coterminously in June 2031. Annualized base rent under the leases is approximately $1.4 million and is subject to annual increases in accordance with the terms of the lease agreement. Remaining lease payments from December 31, 2025 through the end of the lease term total approximately $8.8 million.

We are also party to certain license and collaboration agreements with Biogen, NCI, and Shenyang Sunshine Pharmaceutical Co., Ltd., or 3SBio. We may be obligated to make certain future payments which are contingent upon future events such as our achievement of specified regulatory and commercial milestones, or royalties on net product sales under these agreements. As of December 31, 2025, we were unable to estimate the timing or likelihood of achieving these milestones or generating future product sales. Payments made and remaining obligations on the license agreement with 3SBio are subject to potential reimbursement through deductions to CVR distributions as described in Note 6, “Fair Value Measurements” to our consolidated financial statements included elsewhere in this Annual Report.

Summary of Cash Flows

Year Ended December 31,

Cash (used in) provided by:

Effect of exchange rate changes on cash 45 (21)

Net change in cash, cash equivalents, and restricted cash $ (87,405) $ 135,991

Operating activities

Net cash used in operating activities for the year ended December 31, 2025 was $73.9 million compared to $23.7 million for the year ended December 31, 2024. The increase in net cash used in operating activities of $50.2 million was primarily due to $65.9 million of net loss, adjusted for non-cash items, and $8.0 million of cash used in changes in operating assets and liabilities during the year ended December 31, 2025 compared to $17.9 million of net loss, adjusted for non-cash items, and $5.8 million of cash provided by changes in operating assets and liabilities during the year ended December 31, 2024.

Investing activities

Net cash used in investing activities for the year ended December 31, 2025 was $5.5 million compared to net cash used in investing activities of $8.7 million for the year ended December 31, 2024, a decrease of $3.2 million. The net cash used in investing activities for the years ended December 31, 2025 and 2024 consisted primarily of purchases of property and equipment.

Financing activities

Net cash used in financing activities for the year ended December 31, 2025 was $8.1 million compared to net cash provided by financing activities of $168.4 million for the year ended December 31, 2024, a change of $176.5 million. The net cash used in financing activities for the year ended December 31, 2025 was primarily due to payment on the contingent value

Table of Contents

right liability. The net cash provided by financing activities for the year ended December 31, 2024 was primarily the result of proceeds of the 2024 Private Placement and the 2023 Private Placement.

Recent Accounting Pronouncements

For a discussion of recently adopted or issued accounting pronouncements refer to Note 2, “Summary of Significant Accounting Policies” to our consolidated financial statements included elsewhere in this Annual Report.

Off-Balance Sheet Arrangements

As of December 31, 2025, we did not have any off-balance sheet arrangements as defined in the rules and regulations of the SEC.

Critical Accounting Policies and Use of Estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP. The preparation of these consolidated financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and disclosure of contingent assets and liabilities in our consolidated financial statements. Actual results may differ from these estimates under different assumptions or conditions and could have a material impact on our reported results. While our significant accounting policies are more fully described in the notes to our consolidated financial statements included elsewhere in this Annual Report, we believe the following accounting policies to be the most critical in understanding the judgments and estimates we use in preparing our consolidated financial statements:

Contingent Value Right Liability

The CVRs distributed pursuant to the terms of the CVR Agreement represent financial instruments that are accounted for under the fair value option election in ASC Topic 825, Financial Instruments (ASC 825). Under the fair value option election, the CVRs are initially measured at the aggregate estimated fair value of the CVRs and will be subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. The estimated fair value of the CVR liability was determined using a Monte Carlo simulation model as of December 31, 2025 and 2024 to estimate future cash flows associated with the legacy assets, including the expected milestone and royalty payments under the Sobi License, net of deductions. Changes in fair value of the CVR liability are presented in the consolidated statements of operations and comprehensive loss. The liability value is based on significant inputs not observable in the market such as estimated cash flows, estimated probabilities of success, expected volatility of future revenues, which represent a Level 3 measurement within the fair value hierarchy.

Collaboration and License Revenue Recognition

Revenue is recognized when a customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. Pursuant to ASC Topic 606, Revenue from Contracts with Customers (ASC 606), a customer is a party that has contracted with an entity to obtain goods or services that are an output of the entity’s ordinary activities in exchange for consideration. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, we perform the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract, including whether they are distinct in the context of the contract; (iii) determine the transaction price, including the constraint on variable consideration; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) we satisfy each performance obligation. We only apply the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, we assess the goods or services promised within each contract and determine those that are performance obligations, and assess whether each promised good or service is distinct. If a promised good or service is not distinct, it is combined with other promised goods or services into a performance obligation. We then recognize as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

Collaboration and License Revenue

We currently generate revenue through collaboration and license agreements with strategic collaborators for the development and commercialization of product candidates. Collaboration and license agreements with customers are generally accounted for in accordance with ASC 606. We analyze collaboration arrangements by first assessing whether they are within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808), and evaluate whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and

Table of Contents

rewards that are dependent on the commercial success of such activities. Collaboration agreements with customers that are not within the scope of ASC 808 are accounted for in accordance with ASC 606. To the extent the collaboration agreement is within the scope of ASC 808, we also assess whether any aspects of the agreement are within the scope of other accounting literature (specifically ASC 606). If we conclude that some or all aspects of the agreement are distinct and represent a transaction with a customer, we account for those aspects of the arrangement within the scope of ASC 606. We recognize the shared costs incurred that are not within the scope of other accounting literature as a component of the related expense in the period incurred by analogy to ASC Topic 730, Research and Development (ASC 730), and record reimbursements from counterparties as an offset to the related research and development costs. In determining the appropriate amount of revenue to be recognized as we fulfill our obligations under the agreements in accordance with ASC 606, we perform the five steps above. As part of the accounting for the arrangement, we must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. We use key assumptions to determine the stand-alone selling price, which may include market conditions, reimbursement rates for personnel costs, development timelines and probabilities of regulatory success. The assumptions used to determine the stand-alone selling price and our satisfaction of performance obligations have a material effect on our collaboration and license revenue and may prove to be wrong.

The terms of our arrangements typically include one or more of the following: (i) upfront fees; (ii) milestone payments related to the achievement of development, regulatory, or commercial goals; (iii) royalties on net sales of licensed products; (iv) reimbursements or cost-sharing of research and development expenses; and (v) profit/loss sharing arising from co-promotion arrangements.

Licenses of Intellectual Property

If the license to our intellectual property is determined to be distinct from the other promised goods and services identified in the arrangement, we recognize revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. If not distinct, the license is combined with other promised goods and services in the contract. For licenses that are combined with other promised goods and services, we assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. We evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. Optional licenses are evaluated to determine if they are issued at a discount, and therefore, represent material rights and should be accounted for as separate performance obligations.

Milestone Payments: At the inception of each arrangement that includes developmental and regulatory milestone payments, we evaluate whether the achievement of each milestone specifically relates to our efforts to satisfy a performance obligation or transfer a distinct good or service within a performance obligation. If the achievement of a milestone is considered a direct result of our efforts to satisfy a performance obligation or transfer a distinct good or service and the receipt of the payment is based upon the achievement of the milestone, the associated milestone value is allocated to that distinct good or service. If the milestone payment is not specifically related to our efforts to satisfy a performance obligation or transfer a distinct good or service, the amount is allocated to all performance obligations using the relative standalone selling price method. We also evaluate the milestone to determine whether they are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price to be allocated, otherwise, such amounts are constrained and excluded from the transaction price. At the end of each subsequent reporting period, we re-evaluate the probability of achievement of such development milestones and any related constraint, and if necessary, adjust our estimate of the transaction price. Any such adjustments to the transaction price are allocated to the performance obligations on the same basis as at contract inception. Amounts allocated to a satisfied performance obligation shall be recognized as revenue, or as a reduction of revenue, in the period in which the transaction price changes.

Manufacturing Supply Services: Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are evaluated to determine if they are distinct and optional. For optional services that are distinct, we assess if they are priced at a discount, and therefore, provide a material right to the licensee to be accounted for as separate performance obligations.

Royalties: For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, we will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied) in accordance with the royalty recognition constraint.

Clinical Trial Costs

Clinical trial expenses are a significant component of research and development expenses, and we outsource a significant portion of these costs to third-parties. Third-party clinical trial expenses include patient costs, clinical research organization

Table of Contents

costs and costs for data management. The accrual for site and patient costs includes inputs such as estimates of patient enrollment, patient cycles incurred, clinical site activations, and other pass-through costs. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected on the consolidated balance sheets as a prepaid asset or accrued clinical trial cost. These third-party agreements are generally cancellable, and related costs are recorded as research and development expenses as incurred. Non-refundable advance clinical payments for goods or services that will be used or rendered for future research and development activities are recorded as a prepaid asset and recognized as expense as the related goods are delivered or the related services are performed. We also record accruals for estimated ongoing clinical research and development costs. When evaluating the adequacy of the accrued liabilities, we analyze progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by us materially affecting our results of operations. The historical clinical accrual estimates made by us have not been materially different from the actual costs.

Goodwill

Goodwill represents the amount of consideration paid in excess of the fair value of the identified net assets acquired as a result of our business acquisitions accounted for using the acquisition method of accounting. Goodwill is not amortized and is subject to impairment testing at a reporting unit level on an annual basis or when a triggering event occurs that may indicate the carrying value of the goodwill is impaired. An entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Such qualitative factors include macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, certain assumptions that form the basis of forecasted results (e.g., revenue, discount rates and probability of clinical success) and other relevant events. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that the fair value of the reporting unit is less than its carrying amount.

We evaluate goodwill for impairment at least annually on October 1, or the Assessment Date, and whenever facts and circumstances indicate that their carrying amounts may not be recoverable.

Indefinite-Lived Intangible Assets

Indefinite-lived intangible assets consist of IPR&D. The fair values of IPR&D assets acquired in business combinations are capitalized. These assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are amortized over the remaining useful life or written off, as appropriate.

Intangible assets with indefinite lives, including IPR&D, are tested for impairment if impairment indicators arise and, at a minimum, annually. However, an entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that an indefinite-lived intangible asset’s fair value is less than its carrying amount. Otherwise, no further impairment testing is required. The indefinite-lived intangible asset impairment test consists of a one-step analysis that compares the fair value of the intangible asset with its carrying amount. If the carrying amount of an intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. We consider many factors in evaluating whether the value of our intangible assets with indefinite lives may not be recoverable, including, but not limited to, expected growth rates, the cost of equity and debt capital, general economic conditions, our outlook and market performance of our industry and recent and forecasted financial performance.

We evaluate indefinite-lived intangible assets for impairment at least annually on the Assessment Date, and whenever facts and circumstances indicate that their carrying amounts may not be recoverable.

Warrant Liabilities

In December 2019, we issued the 2019 Warrants in connection with a securities purchase agreement between us and a group of institutional investors and certain members of our Board of Directors. Pursuant to the terms of the 2019 Warrants, we could have been required to settle the common warrants in cash in the event of certain acquisitions of us and, as a result, the 2019 Warrants were required to be measured at fair value and reported as a liability on the balance sheet. The outstanding 2019 Warrants expired on December 23, 2024 in accordance with their terms.

In April 2022, we issued warrants in connection with an underwritten offering of shares of common stock and warrants to purchase shares of common stock, or the 2022 Warrants. Pursuant to the terms of the 2022 Warrants, we could be required to settle the 2022 Warrants in cash in the event we are acquired under certain circumstances and, as a result, the 2022 Warrants are required to be measured at fair value and reported as a liability on the balance sheet.

We recorded the fair value of the 2019 Warrants and 2022 Warrants upon issuance using the Black-Scholes valuation model, and are required to revalue the common warrants at each reporting date and upon exercise or expiration with any

Table of Contents

changes in fair value recorded on our statement of operations. In December 2022, we amended the terms of the outstanding 2019 Warrants held by certain members of our Board of Directors to remove the cash settlement provision (as so amended, the Amended 2019 Warrants). As a result, the Amended 2019 Warrants were remeasured at fair value on December 20, 2022 and reclassified from a liability to equity on the balance sheet.

Inputs used to determine estimated fair value of the common warrant liabilities include the estimated fair value of the underlying stock at the valuation date, the estimated term of the warrants, risk-free interest rates, expected dividends and the expected volatility of the underlying stock. The estimates used to determine the fair value of these common warrants represent our best estimates, but may prove to be wrong. Therefore, the change in fair value of warrant liabilities could be materially different in the future.

Stock-Based Compensation

We account for all stock-based compensation granted to employees and non-employees using a fair value method. Stock-based compensation is measured at the grant date fair value and is recognized over the requisite service period of the awards, usually the vesting period, on a straight-line basis, net of estimated forfeitures. To the extent that actual forfeitures differ from our estimates, the differences are recorded as a cumulative adjustment in the period the estimates were adjusted. Stock-based compensation expense recognized in the consolidated financial statements is based on awards that ultimately vest.

The assumptions used in determining the fair value of stock-based awards represent our best estimates, but the estimates involve inherent uncertainties and the application of our judgment. As a result, if factors change and we use significantly different assumptions or estimates, our stock-based compensation expense could be materially different in the future.

Smaller Reporting Company

We qualify as a “smaller reporting company” under the rules of the Securities Act and the Exchange Act. As a result, we may choose to take advantage of certain scaled disclosure requirements available specifically to smaller reporting companies. We will remain a smaller reporting company until the last day of the fiscal year in which the aggregate market value of our common stock held by non-affiliated persons and entities, or our public float, is more than $700 million as of the last business day of our most recently completed second fiscal quarter, or until the fiscal year following the year in which we have at least $100 million in revenue and at least $250 million in public float as of the last business day of our most recently completed second fiscal quarter.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

We are a smaller reporting company under the rules of the Securities Act and the Exchange Act and are not required to provide this information required under this item.

Item 8. Financial Statements and Supplementary Data

The consolidated financial statements together with the report of our independent registered public company accounting firm, required to be filed pursuant to this Item 8 are appended to this Annual Report. An index of those consolidated financial statements is found in Item 15.

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

None.

Item 9A. Controls and Procedures

Evaluation of Disclosure Controls and Procedures

We maintain disclosure controls and procedures, as defined in Exchange Act Rules 13a-15(e) and 15d-15(e), that are designed to ensure information required to be disclosed by us in reports we file or submit under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms and that such information is accumulated and communicated to our management, including our principal executive officer and principle financial officer, to allow timely decisions regarding required disclosure. A control system, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are achieved. Further, the design of a control system must be balanced against resource constraints, and therefore, the benefits of controls must be considered relative to their costs. Given the inherent limitations in all systems of controls, no evaluation of controls can provide absolute assurance all control issues and instances of fraud, if any, within a company have been detected. These inherent limitations include the realities that judgments in decision-making can be faulty and that breakdowns can occur because of a simple error or mistake. Additionally, controls can be circumvented by the individual acts of some persons, by collusion of two or more people or by management override of controls. The design of any system of controls is also based in part upon certain assumptions about the

Table of Contents

likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions. Over time, controls may become inadequate because of changes in conditions, or the degree of compliance with the policies and procedures may deteriorate. Accordingly, given the inherent limitations in a cost-effective system of controls, financial statement misstatements due to error or fraud may occur and may not be detected. Our disclosure controls and procedures are designed to provide reasonable, not absolute, assurance of achieving their objectives. We conduct periodic evaluations of our system of controls to enhance, where necessary, our control policies and procedures.

Our management, with the participation of our Chief Executive Officer and Chief Financial Officer, evaluated the effectiveness of our disclosure controls and procedures as of the end of the period covered by this Annual Report on Form 10-K. Based upon this evaluation, our Chief Executive Officer and Chief Financial Officer concluded that our disclosure controls and procedures were effective at the reasonable assurance level as of December 31, 2025.

Management’s Annual Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as defined in Exchange Act Rules 13a-15(f) and 15d-15(f), to provide reasonable assurance regarding the reliability of our financial reporting and the preparation of financial statements for external purposes in accordance with U.S. GAAP. Internal control over financial reporting includes our policies and procedures, such as our Code of Business Conduct and Ethics, which (i) require our employees, officers and directors to adhere to certain ethical standards; (ii) require the maintenance of records, in reasonable detail, to help to ensure that our transactions, assets and liabilities are accurately and fairly recorded; (iii) provide reasonable assurance that transactions are authorized by our management and directors and are recorded as necessary to allow for the accurate preparation of financial statements in accordance with U.S. GAAP; and (iv) provide reasonable assurance regarding the safeguarding of our assets and the prevention or timely detection of the unauthorized acquisition, use or disposition of our assets, which could have a material effect on the financial statements. Internal control over financial reporting includes the controls themselves, management’s monitoring of those controls, actions taken to correct any deficiencies identified and oversight of our internal control environment by the Audit Committee of our Board of Directors. Any system of internal control has inherent limitations and therefore may not prevent or detect misstatements. Projections of any evaluation of the effectiveness of internal control over financial reporting to future periods are subject to the risk that controls may become inadequate over time because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Our management assessed the effectiveness of our internal control over financial reporting as of the end of our fiscal year 2025 and has reviewed the results of this assessment with the Audit Committee of our Board of Directors. Management based its assessment on criteria established in “Internal Control - Integrated Framework (2013)” issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based upon this assessment, our management concluded that our internal control over financial reporting was effective as of December 31, 2025.

Changes in Internal Control over Financial Reporting

There have been no changes in our internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) 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.

Attestation Report of the Registered Public Accounting Firm

This Annual Report on Form 10-K does not include an attestation report of our registered public accounting firm due to an exemption established for registrants that are non-accelerated filers.

Item 9B. Other Information

During the fiscal quarter ended December 31, 2025, no officer or director, as defined in Rule 16a-1(f) of the Exchange Act, informed us of the adoption, modification or termination of any “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement,” as those terms are defined in Item 408 of Regulation S-K .

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

Not applicable.

Table of Contents

PART III

Item 10. Directors, Executive Officers and Corporate Governance

Incorporated by reference from the information in our Proxy Statement for our 2026 Annual Meeting of Stockholders, which we will file with the SEC within 120 days of the end of the fiscal year to which this Annual Report on Form 10-K relates.

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

Table of Contents

PART IV

Item 15. Exhibits, Financial Statement Schedules

(a)(1) Financial Statements

See the “Index to Consolidated Financial Statements” on page F-1 below for the list of financial statements filed as part of this report.

(a)(2) Financial Statement Schedules

All financial schedules have been omitted because the required information is either presented in the consolidated financial statements filed as part of this Annual Report on Form 10-K or the notes thereto or is not required.

(a)(3) Exhibits

The following is a list of exhibits filed as part of this Annual Report on Form 10-K.

Incorporated by Reference

ExhibitNumber Exhibit Description Form File No. Exhibit FilingDate

Table of Contents

4.12 Description of Securities — — — Filed herewith

Table of Contents

19.1 Cartesian Therapeutics, Inc. Insider Trading Policy — — — Filed herewith

21.1 Subsidiaries of Cartesian Therapeutics, Inc. — — — Filed herewith

101.SCH Inline XBRL Taxonomy Extension Schema Document — — — Filed herewith

# Indicates management contract or compensatory plan.

Table of Contents

Item 16. Form 10-K Summary

None.

Table of Contents

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

CARTESIAN THERAPEUTICS, INC.

Date: March 9, 2026 By: /s/ Carsten Brunn, Ph.D.

Carsten Brunn, Ph.D.

President, Chief Executive Officer and Chairman of the Board

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed by the following persons on behalf of the registrant in the capacities and on the dates indicated.

Signature Title Date

Carsten Brunn, Ph.D. (Principal Executive Officer)

/s/ Blaine Davis Chief Financial Officer March 9, 2026

Blaine Davis (Principal Financial and Accounting Officer)

/s/ Patrick Zenner Lead Independent Director March 9, 2026

Patrick Zenner

/s/ Timothy C. Barabe Director March 9, 2026

Timothy C. Barabe

/s/ Adrian Bot Director March 9, 2026

Adrian Bot

/s/ Nishan de Silva, M.D. Director March 9, 2026

Nishan de Silva, M.D.

/s/ Murat Kalayoglu, M.D., Ph.D. Director March 9, 2026

Murat Kalayoglu, M.D., Ph.D.

/s/ Kemal Malik MBBS Director March 9, 2026

Kemal Malik, MBBS

/s/ Michael Singer, M.D., Ph.D. Director March 9, 2026

Michael Singer, M.D., Ph.D.

/s/ Timothy Springer, Ph.D. Director March 9, 2026

Timothy Springer, Ph.D.

Table of Contents

Cartesian Therapeutics, Inc. and Subsidiaries

Index to Consolidated Financial Statements Pages

Report of Independent Registered Public Accounting Firm (PCAOB ID: 42) F-2

Consolidated Balance Sheets at December 31, 2025 and 2024 F-5

Notes to Consolidated Financial Statements F-8

F-1

Table of Contents

Report of Independent Registered Public Accounting Firm

To the Stockholders and the Board of Directors of Cartesian Therapeutics, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Cartesian Therapeutics, Inc. and subsidiaries (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations and comprehensive loss, changes in convertible preferred stock and stockholders’ deficit and cash flows for each of the two years in the period ended December 31, 2025, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2025, in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s 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 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 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 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 financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the 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 financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as

F-2

Table of Contents

a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

Valuation of contingent value right

Impairment of Goodwill and Indefinite-Lived Intangibles

F-3

Table of Contents

/s/ Ernst & Young LLP

We have served as the Company’s auditor since 2009.

Boston, Massachusetts

March 9, 2026

F-4

Table of Contents

Cartesian Therapeutics, Inc. and Subsidiaries

Consolidated Balance Sheets

(Amounts in thousands, except share data and par value)

December 31,

Assets

Current assets:

Prepaid expenses and other current assets 3,022 3,144

In-process research and development assets 93,900 150,600

Long-term prepaid expenses and other assets 5,551 518

Liabilities and stockholders’ deficit

Current liabilities:

Accrued expenses and other current liabilities 9,498 12,076

Contingent value right liability — 7,761

Lease liabilities, net of current portion 8,525 11,133

Contingent value right liability, net of current portion 392,100 387,739

Commitments and contingencies (Note 18)

Stockholders’ deficit:

Accumulated other comprehensive loss (4,576) (4,621)

Total liabilities and stockholders’ deficit $ 296,411 $ 435,023

The accompanying notes are an integral part of these consolidated financial statements.

F-5

Table of Contents

Cartesian Therapeutics, Inc. and Subsidiaries

Consolidated Statements of Operations and Comprehensive Loss

(Amounts in thousands, except share and per share data)

Year Ended December 31,

Revenues:

Operating expenses:

Impairment of indefinite-lived intangible and long-lived assets 56,700 7,579

Other income (expense):

Gain on change in fair value of warrant liabilities 3,695 2,558

Loss on change in fair value of forward contract liabilities — (6,890)

Other (expense) income, net (2,010) 606

Total other income (expense), net 3,910 (33,240)

Income tax benefit (expense) 9,193 (287)

Other comprehensive income (loss):

Foreign currency translation adjustment 45 (21)

Net loss per share allocable to common stockholders:

Weighted-average common shares outstanding:

The accompanying notes are an integral part of these consolidated financial statements.

F-5

Table of Contents

Cartesian Therapeutics, Inc. and Subsidiaries

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders’ Deficit

(Amounts in thousands, except share data)

Common stock

Shares Amount Amount Shares Amount Shares Amount Shares Amount

Stock-based compensation expense — — — — — — — — — 6,582 — — 6,582

Currency translation adjustment — — — — — — — — — — — (21) (21)

Stock‐based compensation expense — — — — — — — — — 10,521 — — 10,521

Currency translation adjustment — — — — — — — — — — — 45 45

On April 4, 2024, the Company effected a 1-for-30 reverse split of its issued and outstanding shares of common stock, or the Reverse Stock Split. As a result of the Reverse Stock Split, all figures in this Annual Report on Form 10-K relating to shares of the Company’s common stock (such as share amounts, per share amounts, and conversion rates and prices), including but not limited to, the consolidated financial statements and footnotes included herein, have been adjusted to reflect the Reverse Stock Split for all periods presented.

The accompanying notes are an integral part of these consolidated financial statements.

F-6

Table of Contents

Cartesian Therapeutics, Inc. and Subsidiaries

Consolidated Statements of Cash Flows

(Amounts in thousands)

Year Ended December 31,

Cash flows from operating activities

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

Depreciation and amortization 2,959 1,151

Loss on disposal of property and equipment — 273

Impairment of indefinite-lived intangible and long-lived assets 56,700 7,579

Gain on change in fair value of warrant liabilities (3,695) (2,558)

Loss on change in fair value of CVR liability 4,354 36,900

Loss on change in fair value of forward contract liabilities — 6,890

Loss on impairment of investment 2,000 —

(Benefit) provision for deferred taxes (9,193) 287

Changes in operating assets and liabilities:

Unbilled receivable — 2,981

Prepaid expenses and other assets (5,298) 1,747

Deferred revenue — (5,849)

Accrued expenses and other liabilities (3,588) (6,741)

Net cash used in operating activities (73,941) (23,674)

Cash flows from investing activities

Purchases of property and equipment (5,454) (9,093)

Proceeds from the sale of property and equipment — 351

Net cash used in investing activities (5,454) (8,742)

Cash flows from financing activities

Equity offering costs (624) (66)

Proceeds from exercise of common warrants — 2,877

Proceeds from exercise of stock options 323 1,179

Distribution of Contingent Value Rights (7,754) —

Net cash (used in) provided by financing activities (8,055) 168,428

Effect of exchange rate changes on cash 45 (21)

Net change in cash, cash equivalents, and restricted cash (87,405) 135,991

Cash and cash equivalents at beginning of period 214,279 78,288

Cash and cash equivalents at end of period $ 126,874 $ 214,279

Non-cash investing and financing activities

Purchase of property and equipment not yet paid $ 18 $ 847

Equity offering costs in accrued liabilities $ 30 $ 451

The accompanying notes are an integral part of these consolidated financial statements.

F-7

Table of Contents

Cartesian Therapeutics, Inc. and Subsidiaries

Notes to Consolidated Financial Statements

1. Description of the Business

Cartesian Therapeutics, Inc., or the Company, (formerly known as Selecta Biosciences, Inc., or Selecta) was incorporated in Delaware on December 10, 2007, and is headquartered in Frederick, Maryland. The Company is a late clinical-stage biotechnology company pioneering cell therapy for the treatment of autoimmune diseases. The Company leverages its proprietary technology and manufacturing platform to introduce mRNA into cells to provide a therapeutic effect to patient suffering from a variety of autoimmune conditions. Unlike DNA, mRNA degrades naturally over time without integrating into the cell’s genetic material. Its cell therapies are designed to be dosed repeatedly like conventional drugs, administered in an outpatient setting and given without pre-treatment chemotherapy, which is required with many conventional cell therapies.

On November 13, 2023, the Company acquired, in accordance with the terms of the Agreement and Plan of Merger, or the Merger Agreement, the assets of the Delaware corporation which, immediately prior to the Merger (as defined below), was known as Cartesian Therapeutics, Inc., or Old Cartesian. The transaction was structured as a stock-for-stock transaction pursuant to which all of Old Cartesian’s outstanding shares of capital stock were exchanged based on a fixed exchange ratio for consideration of 224,099 shares of common stock, par value $0.0001 per share, of the Company, or the common stock, and 384,930.724 shares of the newly designated Series A Non-Voting Convertible Preferred Stock, par value $0.0001 per share, or the Series A Preferred Stock, or the Merger. The Series A Preferred Stock is intended to have economic rights similar to the common stock, but with only limited voting rights. Additionally, the Company assumed all outstanding stock options of Old Cartesian. The common stock and Series A Preferred Stock related to the Merger were issued on December 5, 2023.

The Company’s Product Candidates

The Company aims to provide a personalized approach to treating patients that begins with the collection of a patient’s cells which is then used to manufacture the Company’s cell therapy product candidates. Once a patient’s cells have expanded in the Company’s process, mRNA is introduced to deliver a chimeric antigen receptor into the cell. Once the manufacturing process is complete, the product is sent back to the treating physician where they administer six weekly infusions of the Company’s cell therapy candidate to the patient. The Company’s product candidate is specifically designed to target and destroy the pathogenic, self-reactive cell that are the underlying cause of the autoimmune disease, with the goal of creating a precision immune reset for the patient.

Descartes-08, the Company’s lead cell therapy product candidate, is an autologous chimeric antigen receptor T-cell therapy, or CAR-T, product targeting B-cell maturation antigen, or BCMA, in clinical development for the treatment of generalized myasthenia gravis, or MG, and myositis, specifically, moderate to sever multi-refractory dermatomyositis and anti antisynthetase syndrome. In contrast to conventional DNA-based CAR T-cell therapies, the Company’s CAR-T administration is designed to not require preconditioning chemotherapy, to be administered in the outpatient setting and does not carry the risk of genomic integration associated with cancerous transformation. Descartes-08 has been granted Orphan Drug Designation and Regenerative Medicine Advanced Therapy Designation by the U.S. Food and Drug Administration, or FDA, for the treatment of MG, and Rare Pediatric Disease Designation for the treatment of juvenile dermatomyositis.

Liquidity and Management’s Plan

As of December 31, 2025, the Company had an accumulated deficit of $822.4 million. The Company anticipates operating losses to continue for the foreseeable future due to, among other things, costs related to research and development of its product candidates and its administrative organization.

As of December 31, 2025, the Company’s cash, cash equivalents, and restricted cash were $126.9 million, of which $1.7 million was restricted cash related to lease commitments. The Company believes the cash, cash equivalents and restricted cash as of December 31, 2025 will enable it to fund its current planned operations for at least the next 12 months from the date of issuance of these financial statements, though it may pursue additional cash resources through public or private equity or debt financings or by establishing collaborations with other companies. However, there is no guarantee that any of these strategic or financing opportunities will be executed on favorable terms, and some could be dilutive to existing stockholders. Further, the liability associated with the Contingent Value Rights, or CVR, Agreement (as defined below) will be settled solely through cash flow received under the Company’s License and Development Agreement, or as so amended, the Sobi License, with Swedish Orphan Biovitrum AB (publ.), or Sobi, and any other Gross Proceeds (as defined in the CVR Agreement) net of certain agreed deductions. Under the CVR Agreement, 100% of all milestone payments, royalties and other amounts paid to the Company or controlled entities under the Sobi License, and any other Gross Proceeds will be distributed, net of specified deductions, to holders of the CVRs. There is no obligation to the Company to fund any amount related to the CVR liability. See Note 6, “Fair Value Measurements”.

F-8

Table of Contents

If the Company is unable to obtain additional funding on a timely basis, it may be forced to significantly curtail, delay, or discontinue one or more of its planned research or development programs or be unable to expand its operations or otherwise capitalize on its commercialization of its product candidates.

2. Summary of Significant Accounting Policies

Basis of presentation and consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Selecta (RUS), LLC, or Selecta (RUS), a Russian limited liability corporation, Selecta Biosciences Security Corporation, a Massachusetts securities corporation which the Company dissolved in December 2024, and Cartesian Bio, LLC, a Delaware limited liability company, which is a variable interest entity for which the Company is the primary beneficiary and have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification, or ASC and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. All significant intercompany accounts and transactions have been eliminated.

Use of estimates

The preparation of consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The Company’s management considers many factors in selecting appropriate financial accounting policies and controls, and bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. In preparing these consolidated financial statements, management used significant estimates in the following areas, among others: estimated fair value of the intangible assets acquired in connection with the Merger, estimated fair value of the CVRs, deferred income taxes, revenue recognition, estimated accrued research and development expenses, stock-based compensation expense, estimated fair value of the liability-classified warrants, and impairment of goodwill, indefinite-lived intangible assets and long-lived assets. The Company assesses the above estimates on an ongoing basis; however, actual results could materially differ from those estimates.

Segment information

Operating segments are defined as components of an enterprise for which separate and discrete information is available for evaluation by the chief operating decision maker, or the CODM, for the purposes of assessing performance and allocating resources. The Company views its operations and manages its business in one operating segment, which prior to the Merger related to the research and development of nanoparticle immunomodulatory drugs for the treatment and prevention of human diseases and subsequent to the Merger relates to the research and development of cell therapy product candidates. The Company’s CODM function is fulfilled by its Chief Executive Officer. The CODM function assesses performance for the segment and decides how to allocate resources based on consolidated net loss that is also reported on the consolidated statements of operations and comprehensive loss. The CODM function uses net loss to monitor budget versus actual results to assess performance of the segment. Segment assets are the same as total assets on the Company’s consolidated balance sheets. All long-lived assets are located in the United States. Long-lived assets consist of property and equipment, net, and operating lease right-of-use assets.

Cash Equivalents, Marketable Securities and Investments

Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase. Marketable securities consist of securities with remaining maturities greater than 90 days when purchased. The Company classifies these marketable securities as available-for-sale and records them at fair value in the accompanying consolidated balance sheets. Marketable securities with less than one year until maturity are classified as short term, while marketable securities with maturities greater than one year are classified as long term. Unrealized gains or losses are included in accumulated other comprehensive loss. Premiums or discounts from par value are amortized to interest income over the life of the underlying investment. Although available to be sold to meet operating needs or otherwise, securities are generally held through maturity. The cost of securities sold is determined based on the specific identification method for purposes of recording realized gains and losses.

The Company has also in the past invested in equity securities of a company whose securities are not publicly traded and where fair value is not readily available. This investment is recorded using cost minus impairment adjusted for changes in observable prices, depending on our ownership percentage and other factors that suggest the Company has a significant influence. The Company monitors this investment to evaluate whether any increase or decline in its value has occurred, based

F-9

Table of Contents

on the implied value of recent company financings, public market prices of comparable companies and general market conditions. This investment is included in investments in the consolidated balance sheets.

Concentrations of Credit Risk and Off-Balance Sheet Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist primarily of cash, cash equivalents, short-term deposits, investments, accounts receivable, and unbilled receivables. Cash and cash equivalents are deposited with federally insured financial institutions in the United States and may, at times, exceed federally insured limits. Management believes that the financial institutions that hold the Company’s deposits are financially creditworthy and, accordingly, minimal risk exists with respect to those balances.

Fair Value of Financial Instruments

The Company’s financial instruments consist mainly of cash equivalents, restricted cash, accounts receivable, accounts payable, accrued expenses and other current liabilities, investments, warrants to purchase common stock, forward contract liabilities, and contingent value rights. The carrying amounts of cash equivalents, restricted cash, accounts receivable, accounts payable, and accrued expenses and other current liabilities approximate their estimated fair value due to their short-term maturities.

Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level hierarchy is used to prioritize the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements), and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are described below:

Level 1—Level 1 inputs are quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date.

Level 2—Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. If the asset or liability has a specified (contractual) term, a Level 2 input must be observable for substantially the full term of the asset or liability.

Level 3—Level 3 inputs are unobservable inputs for the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date.

To the extent that a valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The fair value of warrant liabilities and contingent value rights are determined using Level 3 inputs.

Fair value is a market-based measure considered from the perspective of a market participant rather than an entity-specific measure. Therefore, even when market assumptions are not readily available, the Company’s own assumptions are set to reflect those that market participants would use in pricing the asset or liability at the measurement date. The Company uses prices and inputs that are current as of the measurement date, including during periods of market dislocation. In periods of market dislocation, the observability of prices and inputs may change for many instruments. This condition could cause an instrument to be reclassified within levels in the fair value hierarchy.

The carrying amounts reflected in the consolidated balance sheet for investments approximate fair value and are assessed for impairment quarterly.

Property and Equipment

Property and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the respective assets, generally seven years for furniture and fixtures, five years for laboratory equipment, software and office equipment and three years for computer equipment. Leasehold improvements are amortized over their useful life or the life of the lease, whichever is shorter. Major additions and betterments are capitalized. Maintenance and repairs, which do not improve or extend the life of the respective assets, are charged to operations as incurred. Costs incurred for construction in progress are recorded as assets and are not amortized until the construction is substantially complete and the assets are ready for their intended use.

F-10

Table of Contents

Impairment of Long-Lived Assets

The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. In order to determine if assets have been impaired, assets are tested at the lowest level for which identifiable independent cash flows are available. An impairment loss is recognized when the sum of projected undiscounted cash flows is less than the carrying value of the asset group. The measurement of the impairment loss to be recognized is based on the difference between the fair value and the carrying value of the asset group. The Company did not recognize an impairment charge on its long-lived assets during the year ended December 31, 2025. The Company recognized an impairment charge on its right of use assets and related furniture and fixtures during the year ended December 31, 2024.

Accumulated Other Comprehensive Loss

Comprehensive loss is defined as the change in the equity of a business entity during a period from transactions and other events and circumstances from non-owner sources. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners. Comprehensive loss consists of: (i) all components of net loss and (ii) all components of comprehensive loss other than net loss, referred to as other comprehensive loss. Other comprehensive loss is comprised of foreign currency translation adjustments.

Collaboration and License Revenue Recognition

Revenue is recognized when a customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. Pursuant to ASC Topic 606, Revenue from Contracts with Customers (ASC 606), a customer is a party that has contracted with an entity to obtain goods or services that are an output of the entity’s ordinary activities in exchange for consideration. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract, including whether they are distinct in the context of the contract; (iii) determine the transaction price, including the constraint on variable consideration; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. If a promised good or service is not distinct, it is combined with other promised goods or services into a performance obligation. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

Collaboration and License Revenue

The Company currently generates its revenue through collaboration and license agreements with strategic collaborators for the development and commercialization of product candidates. Collaboration and license agreements with customers are generally accounted for in accordance with ASC 606. The Company analyzes collaboration arrangements by first assessing whether they are within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808), and evaluates whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. Collaboration agreements with customers that are not within the scope of ASC 808 are accounted for in accordance with ASC 606. To the extent the collaboration agreement is within the scope of ASC 808, the Company also assesses whether any aspects of the agreement are within the scope of other accounting literature (specifically ASC 606). If the Company concludes that some or all aspects of the agreement are distinct and represent a transaction with a customer, the Company accounts for those aspects of the arrangement within the scope of ASC 606. The Company recognizes the shared costs incurred that are not within the scope of other accounting literature as a component of the related expense in the period incurred by analogy to ASC Topic 730, Research and Development (ASC 730), and records reimbursements from counterparties as an offset to the related research and development costs. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under the agreements in accordance with ASC 606, the Company performs the five steps above. As part of the accounting for the arrangement, the Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company uses key assumptions to determine the stand-alone selling price, which may include market conditions, reimbursement rates for personnel costs, development timelines and probabilities of regulatory success.

The terms of the Company’s arrangements typically include one or more of the following: (i) upfront fees; (ii) milestone payments related to the achievement of development, regulatory, or commercial goals; (iii) royalties on net sales of licensed products; (iv) reimbursements or cost-sharing of research and development expenses; and (v) profit/loss sharing arising from co-promotion arrangements.

F-11

Table of Contents

Licenses of Intellectual Property

If the license to the Company’s intellectual property is determined to be distinct from the other promised goods and services identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. If not distinct, the license is combined with other promised goods and services in the contract. For licenses that are combined with other promised goods and services, the Company assesses the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Optional licenses are evaluated to determine if they are issued at a discount, and therefore, represent material rights and accounted for as separate performance obligations.

Milestone Payments

At the inception of each arrangement that includes developmental and regulatory milestone payments, the Company evaluates whether the achievement of each milestone specifically relates to the Company’s efforts to satisfy a performance obligation or transfer a distinct good or service within a performance obligation. If the achievement of a milestone is considered a direct result of the Company’s efforts to satisfy a performance obligation or transfer a distinct good or service and the receipt of the payment is based upon the achievement of the milestone, the associated milestone value is allocated to that distinct good or service. If the milestone payment is not specifically related to the Company’s effort to satisfy a performance obligation or transfer a distinct good or service, the amount is allocated to all performance obligations using the relative standalone selling price method. The Company also evaluates the milestone to determine whether they are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price to be allocated, otherwise, such amounts are constrained and excluded from the transaction price. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the transaction price. Any such adjustments to the transaction price are allocated to the performance obligations on the same basis as at contract inception. Amounts allocated to a satisfied performance obligation shall be recognized as revenue, or as a reduction of revenue, in the period in which the transaction price changes.

Manufacturing Supply Services

Arrangements that include a promise for future supply of drug substance or drug product for either clinical development or commercial supply at the customer’s discretion are evaluated to determine if they are distinct and optional. For optional services that are distinct, the Company assesses if they are priced at a discount, and therefore, provide a material right to the licensee to be accounted for as separate performance obligations.

Royalties

For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied) in accordance with the royalty recognition constraint.

Grant Revenue

The Company has contracts with government-sponsored organizations for research and development related activities that provide for payments for reimbursable costs. The Company recognizes grant revenue from these contracts as it performs services under these arrangements when the funding is committed. Expenses associated with these contracts are recognized when incurred as research and development expense. Grant revenue and related expenses are presented gross in the consolidated statements of operations and comprehensive loss as the Company has determined it is the primary obligor under the arrangements relative to the research and development services it performs as lead technical expert. Amounts incurred that are subject to reimbursement from the sponsor are recorded as accounts receivable on the consolidated balance sheets.

Research and Development Costs

Costs incurred in the research and development of the Company’s products are expensed as incurred. Research and development expenses include costs incurred in performing research and development activities, including salaries and benefits, stock-based compensation expenses, facilities cost, overhead costs, contract services, supplies and other outside costs. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made.

F-12

Table of Contents

Clinical Trial Costs

Clinical trial expenses are a significant component of research and development expenses, and the Company outsources a significant portion of these costs to third-parties. Third-party clinical trial expenses include patient costs, clinical research organization costs and costs for data management. The accrual for site and patient costs includes inputs such as estimates of patient enrollment, patient cycles incurred, clinical site activations, and other pass-through costs. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected on the consolidated balance sheets as a prepaid asset or accrued clinical trial cost. These third-party agreements are generally cancellable, and related costs are recorded as research and development expenses as incurred. Non-refundable advance clinical payments for goods or services that will be used or rendered for future research and development activities are recorded as a prepaid asset and recognized as expense as the related goods are delivered or the related services are performed. The Company also records accruals for estimated ongoing clinical research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical clinical accrual estimates made by the Company have not been materially different from the actual costs.

Income Taxes

The Company provides deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. A valuation allowance is provided to reduce the deferred tax assets to the amount that will more-likely-than-not be realized.

The Company determines whether it is more likely than not that a tax position will be sustained upon examination. If it is not more-likely-than-not that a position will be sustained, none of the benefit attributable to the position is recognized. The tax benefit to be recognized for any tax position that meets the more-likely-than-not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. To date, the Company has not incurred interest and penalties related to uncertain tax positions.

Warrants

The Company determines the accounting classification of warrants that are issued, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480-10, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity, and then in accordance with ASC 815-40, Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock. Under ASC 480, warrants are considered liability classified if the warrants are mandatorily redeemable, obligate the issuer to settle the warrants or the underlying shares by paying cash or other assets, or must or may require settlement by issuing variable number of shares.

If warrants do not meet liability classification under ASC 480-10, the Company assesses the requirements under ASC 815-40, which states that contracts that require or may require the issuer to settle the contract for cash are liabilities recorded at fair value, irrespective of the likelihood of the transaction occurring that triggers the net cash settlement feature. If the warrants do not require liability classification under ASC 815-40, in order to conclude equity classification, the Company assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815-40 or other applicable U.S. GAAP. After all relevant assessments are made, the Company concludes whether the warrants are classified as liability or equity. Liability classified warrants are required to be accounted for at fair value both on the date of issuance and on subsequent accounting period ending dates, with all changes in fair value after the issuance date recorded in the statements of operations as a gain or loss. Equity classified warrants are accounted for at fair value on the issuance date with no changes in fair value recognized after the issuance date.

Stock-Based Compensation

The Company accounts for all stock-based compensation granted to employees and non-employees using a fair value method. Stock-based compensation is measured at the grant date fair value and is recognized over the requisite service period of the awards, usually the vesting period, on a straight-line basis, net of estimated forfeitures. To the extent that actual forfeitures differ from the Company’s estimates, the differences are recorded as a cumulative adjustment in the period the estimates were adjusted. Stock-based compensation expense recognized in the consolidated financial statements is based on awards that ultimately vest.

F-13

Table of Contents

Net Income (Loss) Per Share

The Company applies the two-class method to compute basic and diluted net income (loss) per share attributable to common stockholders when it has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income (loss) available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to share in the earnings as if all income (loss) for the period had been distributed. The Company’s Series A Preferred Stock, Series B Preferred Stock and 2022 Warrants, as defined below, participate in any dividends declared by the Company and are therefore considered to be participating securities. The participating securities are not required to participate in the losses of the Company, and therefore during periods of loss there is no allocation required under the two-class method.

Basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) attributable to common stockholders is computed by adjusting net income (loss) per share attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period, including potentially dilutive common shares. For purposes of this calculation, outstanding options to purchase common stock and Series A Preferred Stock, forward contracts to issue Series A Preferred Stock, restricted stock units, warrants to purchase common stock, contingently issuable shares, Series A Preferred Stock, and Series B Preferred Stock are considered potential dilutive common shares.

Contingent Liabilities

The Company accounts for its contingent liabilities in accordance with ASC Topic 450, Contingencies (ASC 450). A provision is recorded when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. With respect to legal matters, provisions are reviewed and adjusted to reflect the impact of negotiations, estimated settlements, legal rulings, advice of legal counsel and other information and events pertaining to a particular matter.

Leases

The Company accounts for its leases in accordance with ASC Topic 842, Leases (ASC 842), and determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Most leases with a term greater than one year are recognized on the balance sheet as right-of-use assets, lease liabilities and, if applicable, long-term lease liabilities. The Company elected not to recognize leases with an original term less than one year on its balance sheet. Operating lease right-of-use assets and their corresponding lease liabilities are recorded based on the present value of lease payments over the expected remaining lease term. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rates, which are the rates incurred to borrow, on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment.

In accordance with the guidance in ASC 842, the fixed and in-substance fixed contract consideration must be allocated to lease and non-lease components based on their relative fair values. Non-components of a contract (e.g., administrative tasks that do not transfer a good or service to the Company, reimbursement or payment of a lessor’s cost, etc.) do not receive an allocation of the consideration in the contract. Although allocation of consideration of lease and non-lease components is required, the Company elected the practical expedient to not separate lease components (e.g. land, building, etc.) and non-lease components (e.g., common area maintenance, consumables, etc.). The lease component results in an operating right-of-use asset being recorded on the balance sheet and amortized on a straight-line basis as lease expense. Right-of-use assets and operating lease liabilities are remeasured upon certain modifications to leases using the present value of remaining lease payments and the estimated incremental borrowing rate upon lease modification.

The Company enters into lease agreements with terms generally ranging from two to eight years. Some of the Company’s lease agreements include Company options to either extend and/or early terminate the lease, the costs of which are included in its operating lease liabilities to the extent that such options are reasonably certain of being exercised. Leases with renewal options allow the Company to extend the lease term typically between one and five years. When determining the lease term, renewal options reasonably certain of being exercised are included in the lease term. When determining if a renewal option is reasonably certain of being exercised, the Company considers several economic factors, including but not limited to, the significance of leasehold improvements incurred on the property, whether the asset is difficult to replace, underlying contractual obligations, or specific characteristics unique to that particular lease that would make it reasonably certain that the Company would exercise such option. Renewal and termination options were generally not included in the lease term for the Company’s existing operating leases. Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Company recognizes lease expense for these leases on a straight-line basis over the lease term.

F-14

Table of Contents

Acquisitions

The Company evaluates acquisitions of assets and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If the screen is met, the transaction is accounted for as an asset acquisition. If the screen is not met, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs, which would meet the requirements of a business. If determined to be a business combination, the Company accounts for the transaction under the acquisition method of accounting which requires the acquiring entity in a business combination to recognize the fair value of all assets acquired, liabilities assumed, and any non-controlling interest in the acquiree and establishes the acquisition date as the fair value measurement point. Accordingly, the Company recognizes assets acquired and liabilities assumed in business combinations based on the fair value estimates as of the date of acquisition. In accordance with ASC Topic 805, Business Combinations (ASC 805) the Company recognizes and measures goodwill as of the acquisition date, as the excess of the fair value of the consideration paid over the fair value of the identified net assets acquired.

Goodwill

Goodwill represents the amount of consideration paid in excess of the fair value of the identified net assets acquired as a result of the Company’s business acquisitions accounted for using the acquisition method of accounting. Goodwill is not amortized and is subject to impairment testing at a reporting unit level on an annual basis or when a triggering event occurs that may indicate the carrying value of the goodwill is impaired. An entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Such qualitative factors include macroeconomic conditions, industry and market considerations, cost factors, overall financial performance and other relevant events. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that the fair value of the reporting unit is less than its carrying amount.

The Company evaluates goodwill for impairment at least annually on October 1, or the Assessment Date, and whenever facts and circumstances indicate that their carrying amounts may not be recoverable. For the years ended December 31, 2025 and 2024, the Company determined that there was no impairment to goodwill.

Indefinite-Lived Intangible Assets

Indefinite-lived intangible assets consist of in-process research and development, or IPR&D. The fair values of IPR&D assets acquired in business combinations are capitalized. These assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are amortized over the remaining useful life or written off, as appropriate.

Intangible assets with indefinite lives, including IPR&D, are tested for impairment if impairment indicators arise and, at a minimum, annually. However, an entity is permitted to first assess qualitative factors to determine if a quantitative impairment test is necessary. Further testing is only required if the entity determines, based on the qualitative assessment, that it is more likely than not that an indefinite-lived intangible asset’s fair value is less than its carrying amount. Otherwise, no further impairment testing is required. The indefinite-lived intangible asset impairment test consists of a one-step analysis that compares the fair value of the intangible asset with its carrying amount. If the carrying amount of an intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. The Company considers many factors in evaluating whether the value of its intangible assets with indefinite lives may not be recoverable, including, but not limited to, expected growth rates, the cost of equity and debt capital, general economic conditions, the Company’s outlook and market performance of the Company’s industry and recent and forecasted financial performance.

The Company evaluates indefinite-lived intangible assets for impairment at least annually on the Assessment Date, and whenever facts and circumstances indicate that their carrying amounts may not be recoverable. During the year ended December 31, 2025, the Company recorded a $56.7 million impairment related to its IPR&D asset related to Descartes-08 in systemic lupus erythematosus, or SLE. There was no impairment recorded for the year ended December 31, 2024. See Note 3, “Goodwill and Indefinite-Lived Intangible Assets” for more information.

Convertible Preferred Stock

The Company records its convertible preferred stock upon issuance at its fair value. The fair value includes the original issuance price, the settlement of any related forward contract, and is less issuance costs. The Company classifies its convertible preferred stock outside of stockholders’ deficit if the redemption of such shares is outside the Company’s control. For shares classified outside of stockholders’ deficit, the Company does not adjust the carrying value of its convertible preferred stock to redemption value until it is probable of becoming redeemable. As of December 31, 2025 and 2024, there were no conditions

F-15

Table of Contents

that could have required cash redemption of the convertible preferred stock and therefore, all convertible preferred stock were classified within stockholders’ deficit.

Series A Preferred Stock Options

The Company classifies a portion of the fair value of the vested stock options for Series A Preferred Stock equal to the estimated redemption value on the measurement date outside of stockholders’ deficit, if the redemption of the shares underlying the options are outside the Company’s control. Any fair value in excess of the estimated redemption value is recognized as additional paid-in capital. The estimated redemption value is based on the intrinsic value of the option. The Company does not adjust the carrying value of the stock options for Series A Preferred Stock until the underlying Series A Preferred Stock is probable of becoming redeemable. The Company records the stock options for Series A Preferred Stock based on the intrinsic value of the vested options.

Variable Interest Entities

The Company evaluates its variable interests in variable interest entities, or VIEs, and consolidates VIEs when the Company is the primary beneficiary. The Company determines whether it is the primary beneficiary of a VIE based on its assessment of whether the Company possesses both (i) the power to direct the activities that most significantly affect the VIE’s economic performance and (ii) the obligation to absorb losses that could be significant to the VIE or the right to receive benefits that could be significant to the VIE. The Company reevaluates the accounting for its VIEs upon the occurrence of events that could change the primary beneficiary conclusion. The Company determined that it was more likely than not that its investment in Cyrus was unrecoverable. Therefore, the Company recorded an impairment on its investment of $2.0 million during the year ended December 31, 2025. There was no impairment on investment during the year ended December 31, 2024. See Note 4, “Investment” for more details.

Contingent Value Right Liability

The CVRs distributed by the Company pursuant to the terms of the CVR Agreement (as defined below) represent financial instruments that are accounted for under the fair value option election in ASC Topic 825, Financial Instruments (ASC 825). Under the fair value option election, the CVRs are initially measured at the aggregate estimated fair value of the CVRs and will be subsequently remeasured at estimated fair value on a recurring basis at each reporting period date. The estimated fair value of the CVR liability is determined using a Monte Carlo simulation method to estimate future cash flows associated with the legacy assets, including the expected milestone and royalty payments under the Sobi License, net of deductions. Changes in fair value of the liability are presented in the consolidated statements of operations and comprehensive loss. The fair value of the liability is based on significant inputs not observable in the market such as estimated cash flows, estimated probabilities of success and expected volatilities of revenues, which represent Level 3 measurements within the fair value hierarchy.

Forward Contract Liabilities

The Company accounts for contracts related to the future issuance of its common stock or convertible preferred stock as a liability if the underlying shares include a redemption feature that may require the Company to settle the instrument by transferring an asset. A forward contract liability is carried at fair value through the date the underlying shares are issued. Subsequent measurement of the fair value of a forward contract liability is based on the market price of the Company’s common stock, which represent Level 2 inputs within the fair value hierarchy as it’s based on observable market data. Changes in fair value of the liability are presented within change in fair value of forward contract liabilities in the consolidated statements of operations and comprehensive loss.

Recent Accounting Pronouncements

Recently Adopted

In December 2023, the FASB, issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09), which improves the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the effective tax rate reconciliation and income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. The Company adopted the new standard during the year ended December 31, 2025 and the amendment has been applied prospectively. See Note 16, “Income Taxes” for additional information.

Not Yet Adopted

In November 2024, the FASB issued ASU 2024-03, Income Statement Reporting- Comprehensive Income- Expense Disaggregation Disclosures (ASU 2024-03), which requires public companies to disclose, in interim and annual reporting periods, additional information about certain expenses in notes to financial statements, including purchases of inventory,

F-16

Table of Contents

employee compensation, depreciation, amortization of intangible assets, and selling expenses. This guidance will be effective for the annual period beginning the year ended December 31, 2027 and for interim periods beginning January 1, 2028, with early adoption permitted. The Company is currently in the process of evaluating the impact of the standard’s adoption on its consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU 2025-10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities (ASU 2025-10), which establishes authoritative guidance on the recognition, measurement, presentation, and disclosure of government grants. Under ASU 2025-10, government grants are recognized when it is probable that the entity will both comply with the conditions of the grant and the grant will be received. The ASU provides specific accounting models for grants related to assets and grants related to income, including options to recognize government grants as deferred income or as a reduction of the asset’s cost basis. The ASU also requires enhanced disclosures regarding the nature of government grants, significant terms and conditions, accounting policies applied, and amounts recognized in the financial statements. ASU 2025-10 is effective for fiscal years beginning after December 15, 2028, including interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of adopting ASU 2025-10 on its consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements (ASU 2025-11), which clarifies the guidance in Topic 270 to improve the consistency of interim financial reporting. The ASU provides a comprehensive list of required interim disclosures and introduces a disclosure principle requiring entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU 2025-11 is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years, with early adoption permitted. The Company is currently evaluating the impact of adopting ASU 2025-11 on its consolidated financial statements and related disclosures.

3. Goodwill and Indefinite-Lived Intangible Assets

On November 13, 2023, the Company merged with Old Cartesian in accordance with the terms of the Merger Agreement. See Note 1, “Description of the Business” for more information. In connection with Merger, the Company recorded goodwill of approximately $48.2 million and total indefinite-lived intangible assets of $150.6 million, of which $93.9 million is related to Descartes-08 for MG and $56.7 million is related to Descartes-08 for SLE.

Indefinite-Lived Intangible Assets

The Company assesses its intangible assets, consisting of IPR&D related to Descartes-08 for MG and Decartes-08 for SLE, for impairment at least annually on the Assessment Date or whenever facts and circumstances indicate that their carrying amounts may not be recoverable. When testing IPR&D for impairment, the Company may assess qualitative factors for its IPR&D to determine whether it is more likely than not that the fair value of its indefinite-lived assets are less than its carrying amount. The qualitative assessment includes the Company’s consideration of relevant events and circumstances that would affect the Company’s indefinite-lived assets, including macroeconomic, industry and market conditions as well as the Company’s financial performance.

For the annual impairment review during the year ended December 31, 2025, the Company performed a qualitative assessment and determined a quantitative impairment test for both indefinite-lived assets was required, whereas only a qualitative assessment was performed during the year ended December 31, 2024.

As a part of the quantitative impairment test of the Company’s IPR&D assets as of the Assessment Date, an extensive valuation analysis was performed to determine the fair value of the Company’s IPR&D assets using a discounted cash flow approach. The estimates and assumptions used in the discounted cash flow approach are Level 3 inputs and primarily include, but are not limited to, projected revenue, the discount rate, control premiums and probability of success. Based on the analysis performed, the estimated fair value of the Company’s IPR&D assets exceeded their respective carrying value as of the Assessment Date and therefore, there was no impairment to IPR&D assets.

On November 13, 2025 the Company announced a pause in further development of Descartes-08 in SLE, following which it made a further decision that it would no longer pursue the development of Descartes-08 in SLE, or the Triggering Event. As the result of the Triggering Event, the Company re-evaluated its IPR&D asset related to Descartes-08 for SLE. Following this assessment, the Company found that the related IPR&D asset was fully impaired. Therefore, the Company recorded a $56.7 million impairment charge to the IPR&D asset related to Decartes-08 for SLE within “Impairment of indefinite-lived intangible and long-lived assets” in the consolidated statements of operations and comprehensive loss during the year ended December 31, 2025. The Triggering Event had no impact on Descartes-08 for MG and therefore no impairment with respect to Descartes-08 in MG was recorded. There were no impairments recorded during the year ended December 31, 2024.

F-17

Table of Contents

Goodwill

The Company assesses its goodwill for impairment at the reporting unit level at least annually on the Assessment Date and whenever facts and circumstances indicate that their carrying amounts may not be recoverable. When testing goodwill for impairment, the Company may assess qualitative factors for its reporting unit to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill. Alternatively, the Company may bypass this qualitative assessment and perform the quantitative goodwill impairment test.

As a part of the quantitative impairment test of the Company’s goodwill as of the Assessment Date, an extensive valuation analysis was performed to determine the fair value of the Company’s reporting unit using a discounted cash flow approach. The estimates and assumptions used in the discounted cash flow approach are Level 3 inputs and primarily include, but are not limited to, projected revenue, the discount rate, control premiums and probability of success. Based on the analysis performed, the estimated fair value of the Company’s reporting unit exceeded the carrying value as of the Assessment Date, and therefore, there was no impairment to goodwill.

As the result of Triggering Event described above, the Company re-evaluated its goodwill for impairment. The Company used the same valuation approach used as of the Assessment Date, with changes made to estimates and assumptions based on the new facts and circumstances as of the Triggering Event. Based on the analysis performed, the estimated fair value of the Company’s reporting unit exceeded the carrying value, and therefore, there was no impairment to goodwill.

There were no changes to the carrying value of the Company’s goodwill during the years ended December 31, 2025 and 2024.

4. Investment

In 2021, the Company and Cyrus Biotechnology, Inc., or Cyrus, entered into a stock purchase agreement, or the Series B Preferred Stock Purchase Agreement. Pursuant to the Series B Preferred Stock Purchase Agreement, the Company purchased 2,326,934 shares of Cyrus’ Series B Preferred Stock, par value $0.0001 per share, at a purchase price of $0.8595 per share, for $2.0 million.

In accordance with ASC 810, the Company has a variable interest in Cyrus resulting from its equity investment. The Company will share in Cyrus’ expected losses or receive a portion of its expected returns and absorb the variability associated with changes in the entity’s net assets. However, the Company is not the primary beneficiary as it does not have the power to direct the activities most significant to Cyrus, and therefore it is not required to consolidate Cyrus. The Company recognized the $2.0 million investment of Cyrus’ Series B Preferred Stock at cost on the purchase date. The Company has not provided financing to Cyrus other than the amount contractually required by the Series B Preferred Stock Purchase Agreement.

The Company evaluates its investment for impairment whenever events or changes in circumstances indicate that the carrying amount of such investment may be impaired. If a decline in value of the investment is determined to be other than temporary, an impairment loss is recognized in other (expense) income, net in the consolidated statements of operations and comprehensive loss. During the year ended December 31, 2025, the Company determined that it was more likely than not that its investment in Cyrus was unrecoverable. Therefore, the Company recorded an impairment on its investment of $2.0 million and there is no carrying value as of December 31, 2025.

5. Net Loss Per Share Allocable to Common Stockholders

The Company reported a net loss for the years ended December 31, 2025 and 2024. The Company used the treasury stock method to determine the number of dilutive shares for the year ended December 31, 2024. The following table sets forth the

F-18

Table of Contents

computation of basic and diluted net loss per share allocable to common stockholders (in thousands, except share and per-share data):

Year Ended December 31,

Numerator:

Net loss allocable to shares of common stock - basic (130,302) (77,424)

Net loss allocable to shares of common stock - diluted $ (130,302) $ (77,870)

Denominator:

Net loss per share:

The following table represents the potential dilutive shares of common stock excluded from the computation of the diluted net loss per share allocable to common stockholders for all periods presented, as the effect would have been anti-dilutive:

Year Ended December 31,

6. Fair Value Measurements

The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2025 and 2024 (in thousands):

Total Level 1 Level 2 Level 3

Assets:

Money market funds (included in cash equivalents) $ 122,724 $ 122,724 $ — $ —

Liabilities:

Warrant liability $ 141 $ — $ — $ 141

Total Level 1 Level 2 Level 3

Assets:

Money market funds (included in cash equivalents) $ 39,088 $ 39,088 $ — $ —

Liabilities:

Warrant liability $ 3,836 $ — $ — $ 3,836

F-19

Table of Contents

There were no transfers within the fair value hierarchy during the years ended December 31, 2025 and 2024.

Cash, Cash Equivalents, and Restricted Cash

As of December 31, 2025 and 2024, money market funds were classified as cash and cash equivalents on the accompanying consolidated balance sheets as they mature within 90 days from the date of purchase.

As of December 31, 2025, the Company had restricted cash balances relating to secured letters of credit in connection with its real estate leases (see Note 9, “Leases”). The Company’s consolidated statement of cash flows includes the following as of December 31, 2025 and 2024 (in thousands):

Year Ended December 31,

Total cash, cash equivalents, and restricted cash $ 126,874 $ 214,279

Warrants to Purchase Common Stock

In December 2019, the Company issued warrants to purchase common stock in connection with a private placement, or the 2019 Warrants. The outstanding 2019 Warrants expired on December 23, 2024 in accordance with their terms. Pursuant to the terms of the 2019 Warrants, the Company could have been required to settle the 2019 Warrants in cash in the event of certain acquisitions of the Company and, as a result, the 2019 Warrants were required to be measured at fair value and reported as a liability on the balance sheet. On December 20, 2022, the Company amended the terms of the outstanding 2019 Warrants held by certain members of the Board of Directors, or the Amended 2019 Warrants, to remove the cash settlement provision. As a result, the Amended 2019 Warrants were remeasured at fair value on December 20, 2022 and reclassified from a liability to equity on the balance sheet. See Note 11, “Equity” for further discussion on the equity-classified Amended 2019 Warrants.

In April 2022, the Company issued warrants in connection with an underwritten offering, or the 2022 Warrants. Pursuant to the terms of the 2022 Warrants, the Company could be required to settle the 2022 Warrants in cash in the event of an acquisition of the Company under certain circumstances and, as a result, the 2022 Warrants are required to be measured at fair value and reported as a liability on the balance sheet.

The Company recorded the fair value of the 2019 Warrants and the 2022 Warrants upon issuance using the Black-Scholes valuation model and is required to revalue the 2019 Warrants and the 2022 Warrants at each reporting date, with any changes in fair value recorded in the consolidated statements of operations and comprehensive loss. The valuations of the 2019 Warrants and the 2022 Warrants are classified as Level 3 of the fair value hierarchy due to the need to use assumptions in the valuations that are both significant to the fair value measurement and unobservable, including the stock price volatility and the expected life of the 2019 Warrants and the 2022 Warrants. Generally, increases (decreases) in the fair value of the underlying stock and estimated term would result in a directionally similar impact to the fair value measurement. The changes in the fair values of the warrants are reflected in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2025 and 2024.

The estimated fair values of the 2019 Warrants and the 2022 Warrants were determined using the following inputs to the Black-Scholes simulation valuation:

•Estimated fair value of the underlying stock. The Company estimates the fair value of the common stock based on the closing stock price at the end of each reporting period.

•Risk-free interest rate. The risk-free interest rate is based on the U.S. Treasury at the valuation date commensurate with the expected remaining life assumption.

•Dividend rate. The dividend rate is based on the historical rate, which the Company anticipates will remain at zero.

•Expected life. The expected life of the 2019 Warrants was assumed to be equivalent to their remaining contractual term which expired on December 23, 2024. The expected life of the 2022 Warrants is assumed to be equivalent to their remaining contractual term which expires on April 11, 2027.

•Volatility. The Company estimates stock price volatility based on the Company’s historical volatility for a period of time commensurate with the expected remaining life of the warrants.

F-20

RNAC US Equity

RNAC · 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, Financial Statement Schedules

Item 16. Form 10-K Summary

RNAC US Equity☆

RNAC · 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, Financial Statement Schedules

Item 16. Form 10-K Summary

RNAC US Equity