What changed in this filing

/stocks — the workspaceLOADING

Item 9A. Controls and Procedures

2026-03-09 compared with 2025-03-13 · 467 added, 701 removed, 1193 unchanged (49% of the section changed)

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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.

Remediation of Previously Identified Material Weakness

We previously reported a material weakness, identified in 2023, in our internal controls specifically related to the documentation of the assumptions supporting the valuation of the in-process research and development intangible assets acquired in connection with the Old Cartesian material business combination and the initial and on-going contingent value right obligation issued at that time to legacy Selecta stockholders.

This material weakness included a lack of sufficient documentation to provide evidence of the associated management review controls.

Although we have not entered into any business combination transactions since November 2023, the annual impairment testing required for our in-process research and development intangible assets necessitates similar valuation processes and controls.

For example, both could require the development of sophisticated long-range cash flow forecasts, by indication and market, appropriately adjusted for probability of success, which include but are not limited to:

(i) revenues from product sales and/or royalties;

(ii) expenses, including costs of goods sold, research and development, general and administrative and sales and marketing;

(iii) expectations of long-term effective tax rates;

(iv) consideration of capital expenditures which may be required in order to achieve revenue;

and (v) working capital requirements.

The resulting forecasts are then subjected to a discounted cash flow analysis in order to arrive at an estimate of fair value.

A similar cash flow forecasting process and discounted cash flow analysis is utilized at each reporting period to determine the estimated fair value of the contingent value right obligation.

For the Company’s required annual impairment testing (performed as of October 1, 2024) of its in-process research and development intangible assets, management documented and reviewed the significant inputs and assumptions used in the purchase accounting for the Old Cartesian material business combination.

As proscribed in “ASC 350 – Intangibles – Goodwill and Other,” management began with a qualitative assessment to determine whether it was necessary to perform the quantitative testing.

Management’s qualitative assessment resulted in a determination that it was not more likely than not that the Company’s in-process research and development assets were impaired.

Therefore, quantitative testing was not required to be performed.

At each reporting period during fiscal 2024, management documented and reviewed the significant inputs and assumptions used by the Company’s third-party valuation firm to determine the estimated fair value of the contingent value right obligation.

Cash flow forecasts were prepared by management, along with the necessary documentation and memoranda evidencing that the required controls were in place and operating effectively.

These cash flow forecasts were then subjected to discounted cash flow analysis to determine the estimated fair value of the contingent value right obligation.

Based upon management’s assessment, we have concluded that our disclosure controls and procedures were designed and operating effectively as of December 31, 2024 and, therefore, the previously identified material weakness was remediated.

Management’s Annual Report on Internal Control over Financial Reporting

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Changes in Internal Control over Financial Reporting

Except as described above under “—Remediation of Previously Identified Material Weakness,” 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, 2024 that have materially affected, or are reasonably likely to materially affect, our 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 “smaller reporting companies.”

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.

Other Information

On December 23, 2024 , Christopher Jewell , our Chief Scientific Officer , adopted a trading plan intended to satisfy the conditions under Rule 10b5-1(c) of the Exchange Act.

Jewell’s plan provides for the exercise of vested stock options and the potential associated sale of up to 15,000 shares of our common stock until and including December 31, 2025.

The foregoing exercises or sales, if any, will be made in accordance with the prices and formulas set forth in the plan and such plan terminates on the earlier of the date all the shares under the plan are sold and December 31, 2025 .

During the fiscal quarter ended December 31, 2024, no other 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 .

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 .

Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

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8-K 001-37798 2.1 11/13/2023

Restated Certificate of Incorporation of Selecta Biosciences, Inc.

3.1(a) Restated Certificate of Incorporation of Selecta Biosciences, Inc.

8-K 001-37798 3.1 6/29/2016

Certificate of Amendment to the Restated Certificate of Incorporation of Selecta Biosciences, Inc., dated June 21, 2022

3.1(b) Certificate of Amendment to the Restated Certificate of Incorporation of Selecta Biosciences, Inc., dated June 21, 2022

8-K 001-37798 3.1 6/21/2022

Certificate of Amendment to the Restated Certificate of Incorporation of Selecta Biosciences, Inc., dated November 13, 2023

3.1(c) Certificate of Amendment to the Restated Certificate of Incorporation of Selecta Biosciences, Inc., dated November 13, 2023

8-K 001-37798 3.3 11/13/2023

Certificate of Amendment to the Restated Certificate of Incorporation, as amended, of Cartesian Therapeutics, Inc., dated March 28, 2024.

3.1(d) Certificate of Amendment to the Restated Certificate of Incorporation, as amended, of Cartesian Therapeutics, Inc., dated March 28, 2024.

8-K 001-37798 3.2 3/28/2024

3.2 Amended and Restated By-laws of Cartesian Therapeutics, Inc.

10-Q 001-37798 3.2 11/13/2023

001-37798 3.2 10/30/2025

4.1 Specimen Stock Certificate evidencing the shares of common stock

— — — Filed herewith

001-37798 4.1 3/13/2025

4.2 Form of Warrant to Purchase Shares of Series E Preferred Stock, dated December 31, 2015, issued by the Registrant to Oxford Finance LLC and Square One Bank, together with a schedule of warrant holders

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8-K 001-37798 10.2 11/13/2023

Certificate of Designation of Preferences, Rights and Limitations of Series A Non-Voting Convertible Preferred Stock

4.9(a) Certificate of Designation of Preferences, Rights and Limitations of Series A Non-Voting Convertible Preferred Stock

8-K 001-37798 3.4 11/13/2023

Certificate of Amendment to the Certificate of Designation of Series A Non-Voting Convertible Preferred Stock, dated March 26, 2024.

4.9(b) Certificate of Amendment to the Certificate of Designation of Series A Non-Voting Convertible Preferred Stock, dated March 26, 2024.

8-K 001-37798 3.1 3/28/2024

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2018 Employment Inducement Incentive Award Plan, and forms of award agreements thereunder

— — — Filed herewith

10.3 3/13/2025

10.4# Cartesian Therapeutics, Inc.

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10.5# Non-Employee Director Compensation Program

— — — Filed herewith

10.5 3/13/2025

10.6# Form of Indemnification Agreement for Directors and Officers

4 unchanged sentences

S-1 333-211555 10.10 5/24/2016

Lease Agreement by and between BRE-BMR Grove LLC and Selecta Biosciences, Inc.

10.9(a) Lease Agreement by and between BRE-BMR Grove LLC and Selecta Biosciences, Inc.

dated July 23, 2019

10-Q 001-37798 10.3 11/8/2019

First Amendment to Lease by and between BRE-BMR Grove LLC and Selecta Biosciences, Inc.

10.9(b) First Amendment to Lease by and between BRE-BMR Grove LLC and Selecta Biosciences, Inc.

dated September 1, 2022

10-Q 001-37798 10.1 11/3/2022

Lease Agreement by and between 704 Quince Orchard Owner, LLC and Cartesian Therapeutics, Inc.

10.10(a)† Lease Agreement by and between 704 Quince Orchard Owner, LLC and Cartesian Therapeutics, Inc.

dated May 11, 2018

10-K 001-37798 10.11(a) 3/7/2024

First Amendment to Lease Agreement by and between 704 Quince Orchard Owner, LLC and Cartesian Therapeutics, Inc.

10.10(b)† First Amendment to Lease Agreement by and between 704 Quince Orchard Owner, LLC and Cartesian Therapeutics, Inc.

dated March 22, 2021

10-K 001-37798 10.11(b) 3/7/2024

Second Amendment to Lease Agreement by and between 704 Quince Orchard Owner, LLC and Cartesian Therapeutics, Inc.

10.10(c)† Second Amendment to Lease Agreement by and between 704 Quince Orchard Owner, LLC and Cartesian Therapeutics, Inc.

dated May 3, 2021

10-K 001-37798 10.11(c) 3/7/2024

Lease Agreement by and between 7495 RP, LLC and Cartesian Therapeutics, Inc.

10.11(a)† Lease Agreement by and between 7495 RP, LLC and Cartesian Therapeutics, Inc.

dated February 28, 2024

10-K 001-37798 10.12 3/7/2024

First Amendment to Lease Agreement by and between 7495 RP, LLC and the Registrant dated May 7, 2024

10.11(b)† First Amendment to Lease Agreement by and between 7495 RP, LLC and the Registrant dated May 7, 2024

10-Q 001-37798 10.3(b) 5/8/2024

Second Amendment to Lease Agreement by and between 7495 RP, LLC and the Registrant dated August 30, 2024

10.11(c)† Second Amendment to Lease Agreement by and between 7495 RP, LLC and the Registrant dated August 30, 2024

10-Q 001-37798 10.1 11/7/2024

Third Amendment to Lease Agreement by and between 7495 RP, LLC and the Registrant dated March 13, 2025

001-37798 10.1 5/8/2025

Fourth Amendment to Lease Agreement by and between 7495 RP, LLC and the Registrant dated June 26, 2025

001-37798 10.1 8/7/2025

10.12# Employment Agreement, dated as of September 25, 2018, by and between the Registrant and Carsten Brunn, Ph.D.

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8-K 001-37798 10.1 4/1/2024

Employment Agreement, dates as of March 28, 2024, by and between the Registrant and Metin K urtoglu, M.D., Ph.D.

10.15# Employment Agreement, dates as of March 28, 2024, by and between the Registrant and Metin Kurtoglu, M.D., Ph.D.

8-K 001-37798 10.2 4/1/2024

License and Development Agreement, dated as of June 11, 2020, by and between the Registrant and Swedish Orphan Biovitrum AB (Publ)

10.16(a)† License and Development Agreement, dated as of June 11, 2020, by and between the Registrant and Swedish Orphan Biovitrum AB (Publ)

10-Q 001-37798 10.2 8/6/2020

Amendment No.

10.16(b)† Amendment No.

1 to License and Development Agreement, dated as of October 31, 2023, by and between the Registrant and Swedish Orphan Biovitrum AB (Publ)

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S-3 333-283803 1.2 12/13/2024

S eparation Agreement , dated as of October 20 , 2025, by and between the Company and Christopher Jewell

— — — Filed herewith

Separation Agreement, dated as of April 29, 2025, by and between the Company and Metin Kurtoglu

001-37798 10.2 5/8/2025

19.1 Cartesian Therapeutics, Inc.

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Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

— — — Furnished herewith

— — — Filed herewith

97 Cartesian Therapeutics, Inc.

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Carsten Brunn, Ph.D.

President and Chief Executive Officer

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.

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/s/ Carsten Brunn, Ph.D.

President and Chief Executive Officer, and Director March 13, 2025

President, Chief Executive Officer and Chairman of the Board

March 9, 2026

Carsten Brunn, Ph.D.

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Blaine Davis (Principal Financial and Accounting Officer)

/s/ Carrie S.

Cox Director March 13, 2025

/s/ Patrick Zenner Lead Independent Director

March 9, 2026

Patrick Zenner

/s/ Timothy C.

Barabe Director March 9, 2026

/s/ Adrian Bot

Director March 9, 2026

/s/ Nishan de Silva, M.D.

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Timothy Springer, Ph.D.

/s/ Patrick Zenner Director March 13, 2025

Patrick Zenner

Cartesian Therapeutics, Inc.

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Consolidated Statements of Operations and Comprehensive Loss for the years ended December 31, 2025 and 2024

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) for the years ended December 31, 202 4 and 202 3

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Deficit for the years ended December 31, 2025 and 2024

Consolidated Statements of Cash Flows for the years ended December 31, 2025 and 2024

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We have audited the accompanying consolidated balance sheets of Cartesian Therapeutics, Inc.

and subsidiaries (the Company) as of December 31, 2024 and 2023, the related consolidated statements of operations and comprehensive loss, changes in convertible preferred stock and stockholders’ equity (deficit) and cash flows for each of the two years in the period ended December 31, 2024, and the related notes (collectively referred to as the “consolidated financial statements”).

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.

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We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the Audit Committee and that:

(1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments.

The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

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

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

Description of the Matter

As described in Note 3, the Company estimates the fair value of the Contingent Value Right (“CVR”) using a Monte Carlo simulation to estimate future cash flows associated with the legacy assets, including the expected milestone and royalty payments under the Sobi License, net of deductions.

As of December 31, 2025, the Company recorded the contingent value right liability and the contingent value right liability, net of current portion of zero and $392.1 million, respectively.

As described in Note 2, the Company estimates the fair value of the Contingent Value Right (“CVR”) using a Monte Carlo simulation to estimate future cash flows associated with the legacy assets, including the expected milestone and royalty payments under the Company’s License and Development Agreement with Swedish Orphan Biovitrum AB (publ.) as amended, net of deductions.

Changes in the fair value of the liability are presented in the consolidated statements of operations and comprehensive loss.

The liability value is calculated based on significant inputs that are not observable in the market such as estimated cash flows, estimated probabilities of success, and expected volatilities of revenues, which represent a Level 3 measurement within the fair value hierarchy.

For the year ended December 31, 2024, the Company recorded the change in the fair value of the contingent value right liability of $(36.9 million).

As of December 31, 2024, the Company recorded the contingent value right liability and the contingent value right liability, net of current portion of $7.8 million and $387.7 million, respectively.

The liability value is calculated based on significant inputs that are 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.

For the year ended December 31, 2025, the Company recorded a loss on the change in the fair value of the contingent value right liability of $4.4 million.

Auditing the fair value of the CVR liability was complex due to the significant judgment required in estimating the fair value.

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We involved our valuation specialist to assist in evaluating the valuation methodologies and discount rate used to value the CVR liability.

We also performed sensitivity analyses to evaluate the changes in the fair value of the CVR liability that would result from changes in the significant assumptions.

Impairment of Goodwill and Indefinite-Lived Intangibles

Description of the Matter

As of December 31, 2025, the Company’s goodwill and indefinite-lived intangible asset balances were $48.2 million and $93.9 million, respectively.

As disclosed in Note 2 of the consolidated financial statements, goodwill and indefinite-lived intangible assets are tested for impairment annually, or more frequently if events or circumstances indicate the fair value of the reporting unit or the intangible assets may be below its carrying value.

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 discounted cash flows is less than the carrying value of the asset group.

If the carrying value exceeds the fair value, an impairment charge is recognized equal to the difference between the carrying value of the reporting unit and its fair value for goodwill, or the difference between the carrying value of the indefinite-lived intangible assets and its fair value for indefinite-lived intangible assets.

During the year ended December 31, 2025, the Company recorded an impairment charge related to the Descartes-08 for SLE indefinite-lived intangible asset of $56.7 million.

Auditing management’s impairment tests of goodwill and indefinite-lived intangible assets was complex and judgmental due to the measurement uncertainty in determining the fair values of the reporting unit and indefinite-lived intangible assets.

In particular, the fair value estimates of the reporting unit and indefinite-lived intangible assets were sensitive to changes in significant assumptions such as certain assumptions that form the basis of the forecasted results (e.g., revenue, discount rates, control premiums and probability of clinical success).

These significant assumptions are especially challenging to audit as they are forward-looking and could be affected by future economic and market conditions.

How We Addressed the Matter in Our Audit

To test the estimated fair values of the reporting unit and indefinite-lived intangible assets, our audit procedures included, among others, evaluating the Company’s valuation methodology and significant assumptions used by management, and testing the completeness and accuracy of the underlying data supporting the significant assumptions mentioned above.

We performed sensitivity analyses of significant assumptions to evaluate the changes in the fair value of the reporting unit and indefinite-lived intangible assets resulting from changes in the assumptions.

We compared the significant assumptions used by management to current industry and economic trends.

We utilized internal valuation specialists to assist in our evaluation of the Company's valuation methodologies and certain significant assumptions.

In addition, for goodwill we also tested management’s reconciliation of the fair value of the reporting unit to the market capitalization of the Company.

/s/ Ernst & Young LLP

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

December 31, December 31,

Current assets:

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Accounts receivable 1,115 872

Unbilled receivables — 2,981

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

Total current assets 129,276 216,626

Non-current assets:

Property and equipment, net 12,185 9,912

Right-of-use asset, net 5,535 10,068

Right-of-use assets, net 5,601 5,535

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

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Long-term restricted cash 1,735 1,669

Investments 2,000 2,000

Other assets 518 —

Investment — 2,000

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

Total assets $ 296,411 $ 435,023

Liabilities, convertible preferred stock, and stockholders’ deficit

Liabilities and stockholders’ deficit

Current liabilities:

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

Lease liability 2,851 2,166

Deferred revenue — 2,311

Warrant liabilities — 720

Lease liabilities 4,151 2,851

Contingent value right liability — 7,761

Forward contract liabilities — 28,307

Total current liabilities 14,937 22,976

Non-current liabilities:

Lease liability, net of current portion 11,133 8,789

Deferred revenue, net of current portion — 3,538

Warrant liabilities, net of current portion 3,836 5,674

Lease liabilities, net of current portion

Warrant liability 141 3,836

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

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Commitments and contingencies (Note 18)

Series A Preferred Stock, $ 0.0001 par value;

no and 548,375 shares authorized as of December 31, 2024 and December 31, 2023, respectively;

no and 435,120.513 shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively

Options for Series A Preferred Stock — 3,703

Stockholders’ deficit:

Series A Preferred Stock, $ 0.0001 par value;

134,904.563 and no shares authorized as of December 31, 2024 and December 31, 2023, respectively;

120,790.402 and no shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively

134,904.563 shares authorized as of December 31, 2025 and 2024;

120,790.402 shares issued and outstanding as of December 31, 2025 and 2024

Series B Preferred Stock, $ 0.0001 par value;

437,927 and no shares authorized as of December 31, 2024 and December 31, 2023, respectively;

437,927 and no shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively

437,927 shares authorized, issued and outstanding as of December 31, 2025 and 2024

Preferred stock, $ 0.0001 par value;

9,427,168.437 and 9,451,625 shares authorized as of December 31, 2024 and December 31, 2023, respectively;

no shares issued and outstanding as of December 31, 2024 and December 31, 2023

9,427,168.437 shares authorized as of December 31, 2025 and 2024;

no shares issued and outstanding as of December 31, 2025 and 2024

Common stock, $ 0.0001 par value;

350,000,000 shares authorized as of December 31, 2024 and December 31, 2023;

25,767,369 and 5,397,597 shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively

350,000,000 shares authorized as of December 31, 2025 and 2024;

26,011,106 and 25,767,369 shares issued and outstanding as of December 31, 2025 and 2024, respectively

Additional paid-in capital 700,706 689,887

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Total stockholders’ deficit ( 126,240 ) ( 6,802 )

Total liabilities, convertible preferred stock, and stockholders’ deficit $ 435,023 $ 305,050

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

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

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Consolidated Statements of Operations and Comprehensive Loss

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

(Amounts in thousands, except share and per share dat a)

Year Ended December 31,

Collaboration and license revenue $ 38,275 $ 26,004

Grant revenue 638 —

Total revenue 38,913 26,004

Collaboration and license $ 400 $ 38,275

Grant 2,397 638

Total revenues 2,797 38,913

Operating expenses:

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General and administrative 31,468 30,126

Impairment of long-lived assets 7,579 710

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

Total operating expenses 146,202 82,810

Operating loss ( 143,405 ) ( 43,897 )

Other income (expense):

Interest income 6,579 7,386

Foreign currency transaction, net — 38

Interest expense — ( 2,833 )

Change in fair value of warrant liabilities 2,558 12,746

Change in fair value of contingent value right liability ( 36,900 ) ( 18,300 )

Change in fair value of forward contract liabilities ( 6,890 ) ( 149,600 )

Other income, net 606 691

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

Loss on change in fair value of contingent value right liability ( 4,354 ) ( 36,900 )

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 )

Loss before income taxes ( 139,495 ) ( 77,137 )

Income tax (expense) benefit ( 287 ) 19,000

Income tax benefit (expense)

9,193 ( 287 )

Net loss $ ( 130,302 ) $ ( 77,424 )

Other comprehensive loss:

Other comprehensive income (loss):

Foreign currency translation adjustment 45 ( 21 )

Unrealized gain on marketable securities — 11

Total comprehensive loss $ ( 130,257 ) $ ( 77,445 )

Net loss $ ( 130,302 ) $ ( 77,424 )

Net loss per share allocable to common stockholders:

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and Subsidiaries

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

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

(Amounts in thousands, except share data)

Options for Accumulated

Series A Series A Series A Series B Additional other Stockholders’

Preferred Stock Preferred Stock Preferred Stock Preferred Stock Common stock paid-in Accumulated comprehensive equity

Shares Amount Amount Shares Amount Shares Amount Shares Amount capital deficit loss (deficit)

Balance at December 31, 2022

— $ — $ — — $ — — $ — 5,101,459 $ 1 $ 493,322 $ ( 394,937 ) $ ( 4,558 ) $ 93,828

Issuance of Series A Preferred Stock in private placement 619.627 250 — — — — — — — — — — —

Issuance of Series A Preferred Stock in connection with the Merger and settlement of related forward contract 384,930.724 261,753 — — — — — — — — — — —

Issuance of Series A Preferred Stock in connection with private placement and settlement of related forward contract 49,570.162 34,848 — — — — — — — — — — —

Issuance of common stock under Employee Stock Purchase Plan — — — — — — — 6,171 — 231 — — 231

Issuance of vested restricted stock units — — — — — — — 21,226 — — — — —

Issuance of common stock forward in connection with the Merger — — — — — — — — — 2,713 — — 2,713

Issuance of common stock in connection with the Merger and settlement of related forward contract — — — — — — — 224,099 — — — — —

Issuance of replacement options in Merger — — 3,643 — — — — — — 6,801 — — 6,801

Issuance of common stock, license agreement — — — — — — — 44,642 — 1,500 — — 1,500

Settlement of outstanding equity awards at Merger — — — — — — — — — ( 6,169 ) — — ( 6,169 )

Distribution of contingent value rights — — — — — — — — — ( 340,300 ) — — ( 340,300 )

Stock-based compensation expense — — 60 — — — — — — 20,964 — — 20,964

Currency translation adjustment — — — — — — — — — — — ( 53 ) ( 53 )

Unrealized gain on marketable securities — — — — — — — — — — — 11 11

Net loss — — — — — — — — — — ( 219,710 ) — ( 219,710 )

Series A Preferred Stock

Options for Series A Preferred Stock

Series A Preferred Stock

Series B Preferred Stock

Additional paid-in capital

Accumulated deficit

Accumulated other comprehensive loss

Stockholders’ deficit

Shares Amount Amount Shares Amount Shares Amount Shares Amount

Balance at December 31, 2023

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Transfer of Series A Preferred Stock and options for Series A Preferred Stock to permanent equity

( 534,260.839 ) ( 372,048 ) ( 3,703 ) 534,260.839 — — — — — 375,751 — — 375,751

Conversion of Series A Preferred Stock to common stock — — — ( 413,470.437 ) — — — 13,782,324 2 ( 2 ) — — —

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Issuance of common stock upon exercise of warrants

— — — — — — — 65,681 2,877 — — 2,877

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

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— $ — $ — 120,790.402 $ — 437,927 $ — 25,767,369 $ 3 $ 689,887 $ ( 692,071 ) $ ( 4,621 ) $ ( 6,802 )

Issuance of common stock upon exercise of options — — — — — — — 90,444 — 298 — — 298

Issuance of common stock upon vesting of restricted stock units — — — — — — — 153,293 — — — — —

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

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

Net loss — — — — — — — — — — ( 130,302 ) — ( 130,302 )

Balance at December 31, 2025

— $ — $ — 120,790.402 $ — 437,927 $ — 26,011,106 $ 3 $ 700,706 $ ( 822,373 ) $ ( 4,576 ) $ ( 126,240 )

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.

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Consolidated Statements of Cash Flows

(Amounts in thousands)

Year Ended December 31,

Cash flows from operating activities (Amounts in thousands)

Cash flows from operating activities

Net loss $ ( 130,302 ) $ ( 77,424 )

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Depreciation and amortization 2,959 1,151

Amortization of premiums and discounts on marketable securities — ( 79 )

Non‑cash lease expense 778 2,437

Impairment of long-lived assets 7,579 710

Loss on disposal of property and equipment — 273

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

Stock‑based compensation expense 10,521 6,582

Non-cash interest expense — 455

Warrant liabilities revaluation ( 2,558 ) ( 12,746 )

Contingent value right liability revaluation 36,900 18,300

Forward contract liabilities revaluation 6,890 149,600

Loss on extinguishment of debt — 740

Provision (benefit) for deferred taxes 287 ( 19,000 )

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:

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Unbilled receivable — 2,981

Prepaid expenses, deposits and other assets 1,747 ( 1,265 )

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

Accounts payable 1,066 ( 2,927 )

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Cash flows from investing activities

Cash assumed in acquisition of Old Cartesian — 6,561

Proceeds from maturities of marketable securities — 28,254

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

Proceeds from the sale of property and equipment — 351

Net cash (used in) provided by investing activities ( 8,742 ) 34,609

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

Cash flows from financing activities

Proceeds from issuance of Series A Preferred Stock, gross in private placement — 40,000

Repayments of principal, final payment fee, and prepayment penalty on debt — ( 27,457 )

Net proceeds from issuance of common stock and Series B Preferred Stock in private placement — 124,438

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Proceeds from exercise of common warrants — 2,877

Settlement of outstanding equity awards at Merger — ( 6,169 )

Proceeds from exercise of stock options 323 1,179

Proceeds from issuance of common stock under Employee Stock Purchase Plan — 231

Net cash provided by (used in) financing activities 168,428 ( 13,145 )

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, cash equivalents, and restricted cash at beginning of period 78,288 108,038

Cash, cash equivalents, and restricted cash at end of period $ 214,279 $ 78,288

Supplement cash flow information

Cash paid for interest $ — $ 1,853

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

Issuance of common stock, license agreement in stock-based compensation expense $ — $ 1,500

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

Equity offering costs in accrued liabilities $ 30 $ 451

Operating lease right-of-use assets obtained in exchange for operating lease liabilities $ 844 $ 5,246

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

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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 clinical-stage biotechnology company pioneering mRNA cell therapy for the treatment of autoimmune diseases leveraging its proprietary technology and manufacturing platform to introduce one or more mRNA molecules into cells to enhance their function.

The Company believes its mRNA cell therapies have the potential to deliver deep, durable clinical benefit to a broad group of patients with autoimmune diseases because they can be administered over a short period of time, in an outpatient setting, and without pre-treatment chemotherapy.

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, as disclosed in Note 4.

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 the 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.

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.

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.

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The common stock and Series A Preferred Stock related to the Merger were issued on December 5, 2023.

For additional information, see Note 4.

In connection with the Merger, the Company entered into a definitive agreement, or the 2023 Securities Purchase Agreement, for a private investment in public equity transaction, or the 2023 Private Placement, with the Investors (as defined below).

The 2023 Securities Purchase Agreement provides for the issuance to the Investors of an aggregate of 149,330.115 shares of Series A Preferred Stock for an aggregate purchase price of approximately $ 60.25 million.

For additional information, see Note 11.

In connection with the Merger, a contractual contingent value right, or CVR, was distributed to the holders of record of the Company’s common stock and 2022 Warrants (as defined below) as of the close of business on December 4, 2023, but was not distributed to holders of shares of common stock or Series A Preferred Stock issued to stockholders of Old Cartesian or the Investors in the transactions.

Holders of the CVRs will be entitled to receive certain payments from proceeds received by the Company, if any, related to the disposition or monetization of the Company’s legacy assets following the issuance of the CVRs.

For additional information, see Note 6.

On March 27, 2024, the Company’s stockholders approved the Conversion Proposal (as defined below).

For additional information, see Note 11.

Additionally, on March 27, 2024, the Company’s stockholders approved an amendment to the Company’s restated certificate of incorporation, as amended, or the Charter, to effect a reverse stock split of the Company’s issued and outstanding common stock, at a ratio in the range of 1-for-20 and 1-for-30, with such ratio to be determined at the discretion of the Company’s board of directors, or the Board of Directors.

The Board of Directors subsequently approved a final reverse stock split ratio of 1-for-30, and the Company effected the Reverse Stock Split on April 4, 2024.

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), have been adjusted to reflect the Reverse Stock Split for all periods presented, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital.

Shares of common stock underlying outstanding stock options, restricted stock units and warrants were proportionately reduced and the respective exercise prices, if applicable, were proportionately increased in accordance with their terms.

Additionally, the conversion ratio of the Company’s Series A Preferred Stock was proportionally adjusted.

Stockholders entitled to fractional shares as a result of the Reverse Stock Split received a cash payment in lieu of receiving fractional shares.

On July 2, 2024, the Company 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 Non-Voting Convertible Preferred Stock, par value $ 0.0001 per share, or the 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.

On September 20, 2024, the Company’s stockholders approved the Series B Conversion Proposal (as defined below).

For additional information, see Note 11.

The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing.

Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization.

These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities.

The Company’s product candidates are in preclinical and clinical development.

There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, or maintained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable.

Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales.

The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies.

In addition, the Company is dependent upon the services of its employees and consultants.

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

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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 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.

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”.

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.

Basis of Presentation

Principles of 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.

Summary of Significant Accounting Policies

Basis of presentation and consolidation

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 U.S.

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 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 long-lived assets.

The Company assesses the above estimates on an ongoing basis;

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Long-lived assets consist of property and equipment, net, and operating lease right-of-use assets.

Summary of Significant Accounting Policies

Cash Equivalents, Marketable Securities and Investments

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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 we have significant influence.

The Company monitors this investment to evaluate whether any increase or decline in its value has occurred, based on the implied value of recent company financings, public market prices of comparable companies and general market conditions.

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

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.

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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 recognized an impairment charge on its right of use assets and related furniture and fixtures during the year ended December 31, 2024 and on a right-of-use asset during the year ended December 31, 2023.

Debt Issuance Costs

Debt issuance costs and fees paid to lenders are recorded as a direct deduction from the face amount of the related debt.

Debt issuance costs are amortized over the term of the related debt using the effective interest method and recorded as interest expense.

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

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(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 unrealized gains and losses on debt securities and foreign currency translation adjustments.

Other comprehensive loss is comprised of foreign currency translation adjustments.

Collaboration and License Revenue Recognition

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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.

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.

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Stock-based compensation expense recognized in the consolidated financial statements is based on awards that ultimately vest.

Net Loss Per Share

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.

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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 participate in any dividends declared by the Company and are therefore considered to be participating securities.

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.

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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, employee stock purchase plan stock, contingently issuable shares, Series A Preferred Stock, and Series B Preferred Stock are considered potential 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

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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.

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 .

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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 and whenever facts and circumstances indicate that their carrying amounts may not be recoverable.

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.

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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 October 1 and whenever facts and circumstances indicate that their carrying amounts may not be recoverable.

For the years ended December 31, 2024 and 2023, the Company determined that there was no impairment to the IPR&D assets.

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

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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, 2024, there were no conditions that could have required cash redemption of the convertible preferred stock and therefore, all convertible preferred stock were classified within stockholders’ deficit.

As of December 31, 2025 and 2024, there were no conditions

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

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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

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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 discounted cash flow methodology as of December 31, 2023 and a Monte Carlo simulation method as of December 31, 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.

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 liability value is based on significant inputs not observable in the market such as estimated cash flows, estimated probabilities of success, expected volatilities of revenues (Monte Carlo simulation) and risk-adjustment discount rate (discounted cash flow methodology), which represent a Level 3 measurement within the fair value hierarchy.

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 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.

The forward contract liability is carried at fair value through the date the underlying shares are issued.

The fair value of the Series A Preferred Stock forward contract liability was initially measured based on the fair value of the Series A Preferred Stock issued in the 2023 Private Placement (see Note 11), less the purchase price, if any.

Subsequent measurement of the fair value of the Series A Preferred Stock forward contract liability was based on the market price of the Company’s common stock, which represented the redemption and conversion value of the Series A Preferred Stock, less the purchase price, if any, on an as-converted basis.

The remeasurement of the forward contract liability is based on Level 2 inputs within the fair value hierarchy as it’s based on observable market data.

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.

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Recently Adopted

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280):

Improvements to Reportable Segment Disclosures (ASU 2023-07), which requires an enhanced disclosure of significant segment expenses on an annual and interim basis.

This guidance is effective for the annual period beginning the year ended December 31, 2024, and for interim periods beginning January 1, 2025, with early adoption permitted.

The Company adopted the new standard during the year ended December 31, 2024 and the amendments have be applied retrospectively to all prior periods presented in the consolidated financial statements.

See Note 21 for additional information.

Not Yet Adopted

In December 2023, the FASB, issued ASU 2023-09, Income Taxes (Topic 740):

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It also includes certain other amendments to improve the effectiveness of income tax disclosures.

This guidance will be effective for the annual period beginning the year ended December 31, 2025.

Early adoption is permitted.

Upon adoption, the guidance can be applied prospectively or retrospectively.

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 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, employee compensation, depreciation, amortization of intangible assets, and selling expenses.

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

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.

On November 13, 2023, the Company merged with Old Cartesian in accordance with the terms of the Merger Agreement, by and among Selecta, Sakura Merger Sub I, Inc., a wholly owned subsidiary of Selecta, or First Merger Sub, Sakura Merger Sub II, LLC, a wholly owned subsidiary of Selecta, or 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, or the First Merger.

Immediately following the First Merger, Old Cartesian merged with and into Second Merger Sub, pursuant to which Second Merger Sub was the surviving entity, or the Second Merger and, together with the First Merger, the Merger.

In connection with the Second Merger, Old Cartesian changed its name to Cartesian Bio, LLC.

The Merger was intended to qualify as a tax-free reorganization for U.S.

federal income tax purposes.

As a result of the Merger, Selecta changed its corporate name to Cartesian Therapeutics, Inc.

and its common stock began trading on the Nasdaq Global Market under the new trading symbol “RNAC” beginning on November 14, 2023.

The Merger Agreement was unanimously approved by the board of directors, or the Board of Directors, of Selecta and the board of directors of Old Cartesian.

The Merger was consummated substantially concurrently with the entry into the Merger Agreement and was not subject to approval of the Company’s stockholders.

Under the terms of the Merger Agreement, following the consummation of the Merger on November 13, 2023, or the Closing Date, in exchange for 100 % of the outstanding shares of capital stock of Old Cartesian immediately prior to the effective time of the First Merger, the Company agreed to issue to the stockholders of Old Cartesian (i) 224,099 shares of the Company’s common stock and (ii) 384,930.724 shares of Series A Preferred Stock.

The issuance of the shares of common stock and Series A Preferred Stock occurred on December 5, 2023 which was after the December 4, 2023 record date for the distribution of the CVRs (see Note 6);

as such, the Old Cartesian stockholders did not have rights as holders of common stock or holders of Series A Preferred Stock until such issuance on December 5, 2023.

In addition, all outstanding stock options to purchase Old Cartesian common stock were assumed by the Company and converted into stock options to purchase (i) shares of the Company’s common stock or (ii) shares of the Company’s Series A Preferred Stock on terms substantially identical to those in effect prior to Merger Agreement, except for adjustments to the underlying number of shares and the exercise price based on the Merger Agreement exchange ratio.

Pursuant to the Merger Agreement, the Company agreed to hold a stockholders’ meeting, or the Special Meeting, to submit the following proposals to a vote of its stockholders:

(i) the approval of the conversion of shares of Series A Preferred Stock into shares of common stock, or the Conversion Proposal, and (ii) either or both of (A) the approval of an amendment to the Charter to increase the number of shares of common stock authorized under the Charter and (B) the approval of an amendment to the Charter to effect a reverse stock split of all outstanding shares of common stock, in either case (A) or (B) by a number of authorized shares or at a stock split ratio, as the case may be, sufficient to allow the conversion of all shares of Series A Preferred Stock issued in the Merger.

The Special Meeting was held on March 27, 2024, during which the Company’s stockholders approved the Conversion Proposal, among other matters (see Note 11).

The Company concluded the acquisition resulted in the Company obtaining a controlling financial interest in a VIE in accordance with ASC Topic 810, Consolidation (ASC 810) .

The Company determined that Old Cartesian was considered to be a VIE as it did not have sufficient equity to finance its activities without additional subordinated financial support.

Prior to the Closing Date, the primary source of funding for Old Cartesian had been preferred stock financings.

The Company acquired all of the outstanding shares of Old Cartesian and, therefore, is the sole equity holder and primary beneficiary.

The Company has the obligation to absorb the losses and right to receive the benefits of Old Cartesian, and the power to direct the activities that most significantly affect the economic performance of Old Cartesian which the Company considers to be its development

Therefore, the Company is the primary beneficiary.

Further, the Company concluded the VIE qualified as a business and accounted for the transaction as the acquisition of a business in accordance with ASC 805.

As the primary beneficiary, the Company was the acquirer in the transaction.

The Company exchanged the right to receive shares of common stock and Series A Preferred Stock for all of the outstanding equity of Old Cartesian.

The Company determined the rights to receive shares exchanged in the Merger represent a forward contract.

The fair value of the forward contracts was determined based on the fair value of shares of common stock and Series A Preferred Stock underlying the forward contracts as of the acquisition date.

The total purchase price consists of the fair value of the forward contracts in addition to a portion of the fair value of options exchanged in the transaction related to prior service.

Under the acquisition method, the total purchase price of the acquisition was allocated to the net tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values as of the date of the acquisition.

The total fair value of the consideration of $ 168.5 million as of the Closing Date is summarized as follows (in thousands):

Forward contract to issue common stock $ 2,713

Forward contract to issue Series A Preferred Stock 155,308

Stock options allocated to consideration paid 10,444

Total consideration $ 168,465

The Company recorded the assets acquired and liabilities assumed as of the Closing Date based on the information available at that date.

The following table presents the allocation of the purchase price to the estimated fair values of the assets acquired and liabilities assumed as of the Closing Date (in thousands):

Assets acquired:

As of November 13, 2023

Cash and cash equivalents $ 6,561

Prepaid expenses and other current assets 309

Property and equipment, net 215

Right-of-use asset, net 915

In-process research and development assets 150,600

Goodwill 48,163

Liabilities assumed

Accrued expenses and other current liabilities $ 2,530

Lease liability 292

Lease liability, net of current portion 623

Deferred tax liability 34,853

Net assets acquired $ 168,465

The fair value of the IPR&D assets were capitalized as of the Closing Date and are accounted for as indefinite-lived intangible assets until completion or disposition of the assets or abandonment of the associated research and development efforts.

Upon successful completion of the development efforts, the carrying value of each respective IPR&D asset will be amortized over its estimated useful life.

Until that time, the IPR&D assets will be subject to impairment testing and will not be amortized.

The goodwill recorded related to the Merger is the excess of the fair value of the consideration transferred by the acquirer over the fair value of tangible assets, identifiable intangible assets and assumed liabilities as of the Closing Date and is not deductible for tax purposes.

The goodwill balance is primarily attributable to the value of the assembled workforce and deferred tax liabilities associated with the transaction.

The following summarizes the Company’s intangible assets acquired in the Merger (in thousands):

Acquisition Date

Descartes-08 for MG $ 93,900

Descartes-08 for SLE 56,700

Total in-process research and development assets $ 150,600

The fair value of the intangible assets was estimated using the income approach in which the after-tax cash flows were discounted to present value.

The cash flows are based on estimates used to price the transaction, and the discount rates applied

were benchmarked with reference to the implied rate of return from the transaction model as well as the weighted average cost of capital.

For the period from November 13, 2023 to December 31, 2023, Old Cartesian’s revenue and net loss within the consolidated statements of operations and comprehensive loss were $ 0.0 million and $ 1.6 million, respectively.

The following unaudited pro forma financial information reflects the consolidated results of operations of the Company as if the Merger had taken place on January 1, 2022.

The unaudited pro forma financial information is not necessarily indicative of the results of operations as they would have been had the transactions been effected on the assumed date (in thousands):

Year Ended December 31,

Revenue $ 26,004

Net loss $ ( 232,259 )

The Company’s transaction costs of $ 4.9 million were expensed as incurred and included in general and administrative expense in the consolidated statements of operations and comprehensive loss during the year ended December 31, 2023.

The forward contract related to the common stock was recorded as additional paid-in capital as the instrument is indexed to the Company’s common stock.

The forward contract related to the Series A Preferred Stock was recorded as a liability as the underlying Series A Preferred Stock had a redemption feature that may have required the Company to settle the instrument by transferring an asset.

The forward contract was measured at fair value through the date of settlement through the issuance of the shares of Series A Preferred Stock on December 5, 2023.

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.

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.

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.

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.

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 .

Net Loss Per Share Allocable to Common Stockholders

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

The following table sets forth the

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,

Net loss $ ( 77,424 ) $ ( 219,710 )

CVR distribution to participating securities — ( 37,550 )

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

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Weighted-average common shares outstanding - diluted

25,973,329 17,357,943

Net loss per share:

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Year Ended December 31,

Common stock options and RSUs 2,150,273 776,865

Common stock options and restricted stock units

2,993,745 2,150,273

Warrants to purchase common stock 692,272 692,523

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Series B Preferred Stock 437,927 437,927

Forward contract to issue Series A Preferred Stock — 3,304,677

Series A Preferred Stock options — 470,403

Total 8,150,290 7,307,069

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Money market funds (included in cash equivalents)

Total assets $ 39,088 $ 39,088 $ — $ —

Warrant liabilities $ 3,836 $ — $ — $ 3,836

$ 122,724 $ 122,724 $ — $ —

Warrant liability

$ 141 $ — $ — $ 141

Contingent value right liability

Total liabilities $ 399,336 $ — $ — $ 399,336

392,100 — — 392,100

$ 392,241 $ — $ — $ 392,241

December 31, 2024

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Money market funds (included in cash equivalents)

Total assets $ 41,161 $ 41,161 $ — $ —

Warrant liabilities $ 6,394 $ — $ — $ 6,394

$ 39,088 $ 39,088 $ — $ —

Warrant liability

$ 3,836 $ — $ — $ 3,836

Contingent value right liability

Forward contract liabilities 28,307 — 28,307 —

Total liabilities $ 393,301 $ — $ 28,307 $ 364,994

There were no transfers within the fair value hierarchy during the years ended December 31, 2024 or 2023.

395,500 — — 395,500

$ 399,336 $ — $ — $ 399,336

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, 2024, the Company had restricted cash balances relating to secured letters of credit in connection with its real estate leases (see Note 9).

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):

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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 12 for further discussion on the equity-classified Amended 2019 Warrants.

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.

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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 expire on April 11, 2027.

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.

The 2019 Warrants expired on December 23, 2024 and therefore, there were no 2019 Warrants outstanding as of December 31, 2024.

A summary of the Black-Scholes pricing model assumptions used to record the fair value of the 2019 Warrants liability as of December 31, 2023 is as follows:

Risk-free interest rate 4.79 %

Dividend yield —

Expected life (in years) 0.98

Expected volatility 83.67 %

The 2019 Warrants expired on December 23, 2024 and therefore, there were no 2019 Warrants outstanding as of December 31, 2025 or 2024.

A summary of the Black-Scholes pricing model assumptions used to record the fair value of the 2022 Warrants liability is as follows:

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Expected volatility 87.36 % 92.92 %

The following table reflects a roll-forward of fair value for the Company’s Level 3 warrant liabilities (see Note 12), for the year ended December 31, 2024 (in thousands):

Warrant liabilities

The following table reflects a roll-forward of fair value for the Company’s Level 3 warrant liability (see Note 11, “Equity”), for the year ended December 31, 2025 (in thousands):

Warrant liability

Fair value as of December 31, 2024

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On December 6, 2023, as contemplated by the Merger Agreement, the Company entered into a contingent value rights agreement, or the CVR Agreement, pursuant to which each holder of common stock or a 2022 Warrant as of December 4, 2023 was distributed a CVR, issued by the Company for each share of common stock held directly or underlying a 2022 Warrant held by such holder as of December 4, 2023.

Holders of warrants other than the 2022 Warrants will be entitled to receive, upon

exercise of such warrants and in accordance with the terms of the warrants, 30 CVRs per each share of common stock underlying such warrants.

Holders of warrants other than the 2022 Warrants will be entitled to receive, upon exercise of such warrants and in accordance with the terms of the warrants, 30 CVRs per each share of common stock underlying such warrants.

Each CVR entitles its holder to distributions of the following, pro-rated on a per-CVR basis, during the period ending on the date on which the Royalty Term (as defined in the Sobi License) ends, or the Termination Date:

• 100 % of all milestone payments, royalties and other amounts paid to the Company or its controlled affiliates, or the Company Entities, under the Sobi License or, following certain terminations of the Sobi License, any agreement a Company Entity enters into that provides for the development and commercialization of SEL-212;

• 100 % of all cash consideration and the actual liquidation value of any and all non-cash consideration of any kind that is paid to or is actually received by any Company Entity prior to the Termination Date pursuant to an agreement relating to a sale, license, transfer or other disposition of any transferable asset of the Company existing as of immediately prior to the Merger, other than those exclusively licensed under the Sobi License or which the Company Entities are required to continue to own in order to comply with the Sobi License.

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Upon the achievement of a development milestone in June 2024, Sobi became obligated to make a $ 30.0 million payment to the Company and made such payment in July 2024.

The proceeds from this payment, net of deductions specified in the CVR Agreement, is expected to be included in the next scheduled distribution to the holders of the CVR in March 2025.

The proceeds from this payment, net of deductions specified in the CVR Agreement, were included in the scheduled distribution to the holders of the CVR in March 2025.

The CVRs represent financial instruments that are accounted for under the fair value option election in ASC 825.

Under the fair value option election, the CVRs were 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 liability was recorded at the date of approval, November 13, 2023, as a dividend.

The estimated fair value of the CVR liability was determined using a discounted cash flow methodology as of December 31, 2023 and a Monte Carlo simulation model as of December 31, 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.

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 (Monte Carlo simulation model) and risk-adjustment discount rate (discounted cash flow methodology), which represent a Level 3 measurement within the fair value hierarchy.

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 volatility of future revenues, which represent Level 3 measurements within the fair value hierarchy.

The significant inputs used to estimate the fair value of the CVR liability, which represented a financial instrument being accounted for under the fair value option, were as follows:

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Estimated probability of success 95.0 % - 100.0 %

95.0 % - 100.0 %

Expected volatility of future revenues 23.0 % 22.0 %

Estimated cash flow dates 2024 - 2038

Estimated probability of success 95.0 %

Risk-adjusted discount rate 13.7 %

The following table reflects a roll-forward of fair value for the Company’s Level 3 CVR liability for the year ended December 31, 2025 (in thousands):

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Fair value as of December 31, 2024

Distributions

Change in fair value

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Forward Contract Liabilities

Merger Consideration

In connection with the Merger, the Company entered into a contract for the issuance of 384,930.724 shares of Series A Preferred Stock as part of the consideration transferred.

The fair value of the forward contract at the Closing Date was $ 155.3 million.

The non-cash settlement of this liability occurred on December 5, 2023 with the issuance of the Series A Preferred Stock for $ 261.8 million.

2023 Private Placement

The Company entered into a contract for the issuance of 149,330.115 shares of Series A Preferred Stock as part of the 2023 Private Placement which was settled in multiple tranches.

The Company determined the obligation to issue 148,710.488 shares of Series A Preferred Stock to Dr.

Springer, a member of the Company’s Board of Directors, and TAS Partners LLC, an affiliate of Dr.

The Company determined the obligation to issue 148,710.488 shares of Series A Preferred Stock to Timothy A.

Springer, Ph.D., a member of the Company’s Board of Directors, and TAS Partners LLC, an affiliate of Dr.

Springer, represented a forward contract.

The initial fair value of the forward contract liability on November 13, 2023 was insignificant as the fair value of the underlying Series A Preferred Stock was equal to the purchase price of the Series A Preferred Stock as agreed upon in the 2023 Private Placement.

See Note 10, “Convertible Preferred Stock.” The initial fair value of the forward contract liability on November 13, 2023 was insignificant as the fair value of the underlying Series A Preferred Stock was equal to the purchase price of the Series A Preferred Stock as agreed upon in the 2023 Private Placement.

Subsequent measurement of the fair value of the forward contract liability was based on the market price of the Company’s common stock, which represented the redemption and conversion value of the Series A Preferred Stock, less the purchase price, on an as-converted basis.

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The non-cash settlement of the remaining second and third tranches occurred on January 12, 2024 and February 11, 2024, respectively, for a total of $ 35.2 million.

The following table presents changes in the forward contract liabilities for the periods presented (in thousands):

Forward contract liabilities

Fair value as of December 31, 2023

Settlements ( 35,197 )

Change in fair value 6,890

Fair value as of December 31, 2024

Property and Equipment

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Total property and equipment 16,918 12,269

Less accumulated depreciation ( 2,357 ) ( 5,728 )

Accumulated depreciation

( 4,733 ) ( 2,357 )

Property and equipment, net $ 12,185 $ 9,912

See Note 9 for details regarding the impairment loss the Company recognized for certain furniture and fixtures during the year ended December 31, 2024.

See Note 9, “Leases” for details regarding the impairment loss the Company recognized for certain furniture and fixtures during the year ended December 31, 2024.

Depreciation expense was $ 2.4 million and $ 1.2 million for the years ended December 31, 2025 and 2024, respectively.

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Payroll and employee related expenses $ 3,985 $ 3,534

Collaboration and licensing 320 55

Accrued patent fees 205 813

Accrued external research and development costs 2,987 4,896

Accrued research and development costs 2,521 2,987

Accrued professional and consulting services 2,059 3,674

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The discount rate of 14 % was determined based on the Company’s incremental borrowing rate adjusted for the lease term.

On March 13, 2025, the Company and the Landlord entered into the third amendment to the Frederick Lease Agreement, or the Third Frederick Lease Agreement Amendment, providing for the expansion of the premises leased pursuant to the Frederick Lease Agreement, First Fredrick Lease Agreement Amendment and Second Fredrick Lease Agreement Amendment by approximately 6,439 square feet.

In connection with the expansion of the leased premises, the Company is obligated to pay $ 0.2 million in additional annual base rent for the first year of the term, which is subject to an annual upward adjustment of 3 % of the then-current rental rate, as well as its share of operating costs and taxes.

The lease commenced on November 1, 2025, which was the date the Landlord delivered full possession of the premises to the Company and will be coterminous with the Frederick Lease Agreement.

The Company assessed the classification of the lease at the commencement date and concluded it should be accounted for as an operating lease.

The Company recorded a lease liability and right-of-use asset each of $ 0.8 million on the commencement date.

The discount rate of 14 % was determined based on the Company’s incremental borrowing rate adjusted for the lease term.

The Company secured a letter of credit from Silicon Valley Bank, a division of First-Citizens Bank & Trust Company (successor by purchase to the Federal Deposit Insurance Corporation as Receiver for Silicon Valley Bridge Bank, N.A.

(as successor to Silicon Valley Bank)), or SVB, for $ 0.3 million for the Frederick Lease Agreement, the First Frederick Lease Agreement Amendment and the Second Frederick Lease Agreement Amendment, which is recognized as long-term restricted cash as of December 31, 2024 and renews automatically each year.

(as successor to Silicon Valley Bank)), or SVB, for $ 0.3 million for the Frederick Lease Agreement, the First Frederick Lease Agreement Amendment, the Second Frederick Lease Agreement Amendment and the Third Frederick Lease Agreement Amendment which is recognized as long-term restricted cash as of December 31, 2025, and 2024 and renews automatically each year.

65 Grove Street Lease

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The change of consideration in the contract was accounted for as a lease modification and the right-of-use asset and lease liability were remeasured at the modification date of October 24, 2022.

The discount rate of 11.9 % was determined based on the Company’s incremental borrowing rate adjusted for the lease term including any reasonably certain renewal periods as of October 24, 2022, resulting in a decrease of less than $ 0.1 million to both the right-of-use asset and lease liabilities.

The discount rate of 11.9 % was determined based on the Company’s incremental borrowing rate adjusted for the lease term including any reasonably certain

renewal periods as of October 24, 2022, resulting in a decrease of less than $ 0.1 million to both the right-of-use asset and lease liabilities.

In May 2023, the Company received notice from BRE-BMR Grove LLC that the requirements to reduce the amount of the letter of credit for the Watertown Lease Agreement had been met.

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for $ 1.4 million, which is recognized as long-term restricted cash as of December 31, 2025 and 2024, and renews automatically each year.

The $ 1.6 million letter of credit with SVB was released from restriction and returned to the Company on July 17, 2023, and therefore was reclassified into cash and cash equivalents in the consolidated balance sheets.

On October 31, 2023, in connection with entering into Amendment No.

1 to the License and Development Agreement with Sobi as described in Note 14, the Company entered into a sublease agreement with Sobi to sublease approximately 5,600 square feet of space currently rented by the Company at 65 Grove Street, Watertown, Massachusetts for which Sobi paid $ 1.0 million upfront rental payment.

1 to the License and Development Agreement with Sobi as described in Note 13 “Revenue Arrangements,” the Company entered into a sublease agreement with Sobi to sublease approximately 5,600 square feet of space currently rented by the Company at 65 Grove Street, Watertown, Massachusetts for which Sobi paid $ 1.0 million upfront rental payment.

The sublease commenced on November 6, 2023, when the Company, Sobi, and BRE-BMR Grove LLC, executed a Consent to Sublease.

The term of the sublease expired on November 5, 2024 with no option to extend the sublease term.

As of December 31, 2023, deferred rent of $ 0.8 million is included within accrued expenses and other current liabilities in the consolidated balance sheet.

During the year ended December 31, 2023, the Company determined that the right-of-use asset related to the operating lease for approximately 7,216 square feet at 65 Grove Street was partially impaired as of November 30, 2023.

As a result, the Company recognized a $ 0.7 million right-of-use asset impairment charge in impairment of long-lived assets on its consolidated statements of operations and comprehensive loss during the year ended December 31, 2023.

As a result of the expiration of the sublease to Sobi in November 2024 and the Company’s decision to cease use of its office and laboratory space at 65 Grove Street, Watertown, Massachusetts, the Company assessed the right-of-use assets and related furniture and fixtures associated with the Watertown Lease Agreement and Watertown Lease Agreement Amendment

for impairment.

The carrying value of each asset group was compared against the future net undiscounted cash flows projected to be generated over the remaining lease terms.

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As a result of this assessment, which included unrecoverable operating and maintenance costs, the Company determined that each asset group was fully impaired.

As such, an impairment charge of $ 7.6 million was recognized during the year ended December 31, 2024, $ 7.4 million of which related to the right-of-use assets and $ 0.2 million related to property and equipment.

As such, an impairment charge of $ 7.6 million was recognized during the year ended December 31, 2024 within “Impairment of indefinite-lived intangible and long-lived assets” in the consolidated statements of operations and comprehensive loss, $ 7.4 million of which related to the right-of-use assets and $ 0.2 million related to property and equipment.

704 Quince Orchard Road Leases

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The discount rate of 11.5 % was determined based on the Company’s incremental borrowing rate adjusted for the lease term.

Rent expense for the years ended December 31, 2024 and 2023 was $ 5.5 million, $ 3.8 million, respectively.

Rent expense for the years ended December 31, 2025 and 2024 was $ 4.2 million and $ 5.5 million, respectively.

For the years ended December 31, 2025 and 2024, the components of lease costs were as follows (in thousands):

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The maturity of the Company’s operating lease liabilities as of December 31, 2025 were as follows (in thousands):

December 31, 2025

Thereafter 852

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$ 3,662 $ 3,559

Other than the initial recording of the right-of-use assets and lease liabilities for the Frederick Lease Agreement, First Frederick Lease Agreement Amendment, and Second Frederick Lease Agreement Amendment during the year ended December 31, 2024, the impairments on the right-of-use assets for the Watertown Lease Agreement and Watertown Lease Agreement Amendment during the years ended December 31, 2024 and 2023, as applicable, and the assumption of the right-of-use assets and lease liabilities in connection with the Merger during the year ended December 31, 2023, which were non-cash, the changes in the Company’s right-of-use assets and lease liabilities for the years ended December 31, 2024 and 2023 are reflected in the non-cash lease expense and accrued expenses and other liabilities, respectively, in the consolidated statements of cash flows.

Other than the initial recording of the right-of-use assets and lease liabilities for the Third Fredrick Lease Amendment during year ended December 31, 2025, and the Frederick Lease Agreement, First Frederick Lease Agreement Amendment, the Second Frederick Lease Agreement Amendment and impairment on the right-of-use assets for the Watertown Lease Agreement and Watertown Lease Agreement Amendment during the year ended December 31, 2024, which were non-cash, the changes in the Company’s right-of-use assets and lease liabilities for the years ended December 31, 2025 and 2024 are reflected in the non-cash lease expense and accrued expenses and other liabilities, respectively, in the consolidated statements of cash flows.

The following summarizes additional information related to the Company’s operating leases:

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Weighted-average discount rate 12.1 % 11.7 %

2020 Term Loan

On August 31, 2020, the Company entered into a Loan and Security Agreement with Oxford Finance LLC, or Oxford, and Silicon Valley Bank, or the Loan and Security Agreement, and such facility, the 2020 Term Loan.

On March 10, 2023, Silicon Valley Bank was closed by the California Department of Financial Protection and Innovation, and the Federal Deposit Insurance Corporation, or the FDIC, was appointed as receiver.

On March 13, 2023, the FDIC announced that all of Silicon Valley Bank’s deposits and substantially all of its assets had been transferred to a newly created, full-service, FDIC-operated bridge bank, Silicon Valley Bridge Bank, N.A., or SVBB.

SVBB assumed all loans that were previously held by Silicon Valley Bank.

On March 27, 2023, First-Citizens Bank & Trust Company assumed all of SVBB’s customer deposits and certain other liabilities and acquired substantially all of SVBB’s loans and certain other assets from the FDIC, including the 2020 Term Loan.

On September 11, 2023, the Company entered into a payoff letter with Oxford and SVB, pursuant to which the Company paid all outstanding amounts under the 2020 Term Loan, together with accrued interest and a prepayment penalty, resulting in the full extinguishment of the 2020 Term Loan.

The total payoff amount was $ 22.3 million, consisting of the remaining principal amount due of $ 19.8 million, the final payment fee of $ 2.3 million, the prepayment penalty of $ 0.2 million, and less than $ 0.1 million of accrued interest.

During the year ended December 31, 2023, the Company recorded a loss of $ 0.7 million on the extinguishment of the 2020 Term Loan, consisting of the prepayment penalty of $ 0.2 million and the write-off of $ 0.5 million of unamortized debt issuance costs and venture debt termination fee, which was included within interest expense in the consolidated statements of operations and comprehensive loss.

As of December 31, 2024 and 2023, the Company had no outstanding borrowings.

During the year ended December 31, 2024, the Company recognized no interest expense.

During the year ended December 31, 2023, the Company recognized $ 2.1 million of interest expense related to the 2020 Term Loan.

Convertible Preferred Stock

Series B Preferred Stock

The Certificate of Designation of Preferences, Rights, and Limitations of the Series B Non-Voting Convertible Preferred Stock, or the Series B Certificate of Designation, was filed with the Secretary of State of the State of Delaware on July 2, 2024, and provided for the designation of shares of Series B Preferred Stock and authorized the issuance of 2,937,903 shares of Series B Preferred Stock.

Additionally, on July 2, 2024, the Company entered into the 2024 Securities Purchase Agreement with certain institutional and accredited investors, or the Purchasers.

The Purchasers included (i) Dr.

Springer, a member of the Company’s Board of Directors;

and provided for the designation of shares of Series B Preferred Stock and authorized the issuance of 2,937,903 shares of Series B Preferred Stock.

Additionally, on July 2, 2024, the Company 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 Non-Voting Convertible Preferred Stock, par value $ 0.0001 per share, or the Series B Preferred Stock, each at a purchase price of $ 20.00 per share to certain institutional and accredited investors, or the Purchasers.

The Purchasers included (i) Timothy A.

Springer, Ph.D., a member of the Company’s Board of Directors;

(ii) TAS Partners LLC, an affiliate of Dr.

Springer, and (iii) Dr.

Chafen Lu, Dr.

Springer, and (iii) Chafen Lu, Ph.D., Dr.

Springer’s wife.

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The Series B Preferred Stock has the following rights and preferences:

• Conversion:

Prior to the stockholder approval of the Series B Conversion Proposal the Series B Preferred Stock were not convertible into shares of common stock.

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Each share of Series B Preferred Stock outstanding that was not automatically converted into common stock as a result of the stockholder approval of the Series B Conversion Proposal shall be convertible at any time at the option of the holder following stockholder approval of the Series B Conversion Proposal, only to the extent the beneficial ownership limitation does not apply to the shares of Series B Preferred Stock to be converted.

• Redemption:

The Series B Preferred Stock is not redeemable.

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However, as long as any shares of Series B Preferred Stock are outstanding, the Company will not, without the affirmative vote of the holders of a majority of the then-outstanding shares of the Series B Preferred Stock, (a) alter or change adversely the powers, preferences or rights given to the Series B Preferred Stock, (b) alter or amend the Series B Certificate of Designation, or (c) amend the Charter or other organizational documents in any manner that alters or changes the preferences, rights, privileges, or powers of, or restrictions provided for the benefit of the holders of Series B Preferred Stock.

• Liquidation:

The holders of Series B Preferred Stock shall rank on parity with the holders of common stock and the holders of Series A Preferred Stock as to distributions of assets upon liquidation, dissolution or winding up of the Company, whether voluntarily or involuntarily.

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The Certificate of Designation of Preferences, Rights, and Limitations of the Series A Non-Voting Convertible Preferred Stock, or the Series A Certificate of Designation, was filed on November 13, 2023, which provided for the designation of shares of the Series A Preferred Stock and authorized the issuance of 548,375 shares of Series A Preferred Stock.

Additionally on November 13, 2023, the Company entered into the 2023 Securities Purchase Agreement with (i) Dr.

Springer, a member of the Company’s Board of Directors;

Additionally on November 13, 2023, the Company entered into the 2023 Securities Purchase Agreement with (i) Timothy A.

Springer, Ph.D., a member of the Company’s 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 Dr.

Murat Kalayoglu, a co-founder and the former chief executive officer of Old Cartesian, who joined the Company’s Board of Directors effective immediately after the effective

time of the Merger, or the Investors.

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 the Company’s Board of Directors effective immediately after the effective time of the Merger, or the Investors.

Pursuant to the 2023 Securities Purchase Agreement, the Company agreed to issue and sell an aggregate of 149,330.115 shares of Series A Preferred Stock for an aggregate purchase price of $ 60.25 million in the 2023 Private Placement.

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Springer in the first tranche, (ii) 49,570.163 shares of Series A Preferred Stock were issued to Dr.

Springer in the second tranche, and (iii) 49,570.163 shares of Series A Preferred Stock were issued to Dr.

Springer in the second tranche, and (iii) 49,570.163 shares of

Series A Preferred Stock were issued to Dr.

Springer in the third tranche.

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A portion of the liability was settled with the initial issuance of 49,570.162 shares of Series A Preferred Stock on December 13, 2023.

The remaining portion of the forward contract liability was settled upon the issuance of 49,570.163 shares of Series A Preferred Stock each on January 12, 2024 and February 11, 2024, respectively (see Note 6).

On December 5, 2023, the Company issued 384,930.724 shares of Series A Preferred Stock as part of its consideration transferred in connection with the Merger which settled the related forward contract liability (see Note 6).

On March 26, 2024, the Company, with the consent of the requisite holders of Series A Preferred Stock, amended the Series A Certificate of Designation such that the automatic conversion of the Series A Preferred Stock into common stock, or the Automatic Conversion, would occur eight business days following stockholder approval of the Conversion Proposal.

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The Series A Preferred Stock has the following rights and preferences:

• Conversion:

Prior to the stockholder approval of the Conversion Proposal, the Series A Preferred Shares were not convertible.

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Each share of Series A Preferred Stock outstanding that was not otherwise automatically converted into common stock as a result of the beneficial ownership limitation shall be convertible at any time at the option of the holder following stockholder approval of the Conversion Proposal, only to the extent the beneficial ownership limitation does not apply to the shares of Series A Preferred Stock to be converted.

• Redemption:

Prior to the stockholder approval of the Conversion Proposal, each share of Series A Preferred Stock was redeemable at the option of the holder at any time following the date that was 18 months after the initial issuance date of the Series A Preferred Stock, other than any shares of Series A Preferred Stock that would not have been convertible into shares of common stock as a result of the beneficial ownership limitation referred to above.

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However, as long as any shares of Series A Preferred Stock are outstanding, the Company will not, without the affirmative vote of the holders of a majority of the then-outstanding shares of the Series A Preferred Stock, (a) alter or change adversely the powers, preferences or rights given to the Series A Preferred Stock, (b) alter or amend the Series A Certificate of Designation, (c) amend the Charter or other organizational documents in any manner that adversely affects any rights of the holders of Series A Preferred Stock, (d) issue further shares of Series A Preferred Stock (other than in connection with the exercise of the stock options to purchase Series A Preferred Stock) or increase or decrease (other than by conversion) the number of authorized shares of Series A Preferred Stock, (e) prior to the stockholder approval of the Conversion Proposal or at any time while at least 30 % of the originally issued Series A Preferred Stock remains issued and outstanding, consummate either (A) a Fundamental Transaction (as defined in the Series A Certificate of Designation) or (B) any merger or consolidation of the Company or other business combination in which the stockholders of the Company immediately before such transaction do not hold at least a majority of the capital stock of the Company immediately after such transaction, (f) amend or fail to comply with, in any manner that would be reasonably likely to prevent, impede or materially delay the conversion (or the stockholder approval thereof), or terminate, any of the stockholder support agreements entered into in connection with the Merger, or the Support Agreements, or agree to any transfer, sale or disposition of such shares subject to the Support Agreements (except for such transfers, sales or dispositions with respect to which the approval of the Company is not required pursuant to the applicable Support Agreement) or (g) enter into any agreement with respect to any of the foregoing.

• Liquidation:

The holders of Series A Preferred Stock shall rank on parity with the common stockholders and the holders of Series B Preferred Stock as to distributions of assets upon liquidation, dissolution or winding up of the Company, whether voluntarily or involuntarily.

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Equity Financings

2024 Private Placement

On July 2, 2024, the Company and the Purchasers entered into the 2024 Securities Purchase Agreement for the 2024 Private Placement.

Pursuant to the 2024 Securities Purchase Agreement, the Purchasers agreed to purchase an aggregate of 3,563,247 shares of common stock and 2,937,903 shares of Series B Preferred Stock, inclusive of 2,359,500 shares of Series B Preferred Stock purchased by directors and executive officers of the Company, and related parties thereto, each at a price per share of $ 20.00 .

The 2024 Private Placement resulted in gross proceeds of approximately $ 130.0 million before deducting placement agent fees and other offering expenses.

On December 5, 2023, the Company issued 224,099 shares of common stock as part of its consideration transferred in connection with the Merger which settled the related equity-classified forward contract (see Note 4).

Underwritten Offering

On April 6, 2022, the Company entered into an underwriting agreement with SVB Securities LLC (now known as Leerink Partners LLC), as representative of the several underwriters named therein, relating to an underwritten offering of 914,285 shares of the Company’s common stock and 2022 Warrants to purchase up to 685,712 shares of common stock, or the 2022 Offering.

Each share and accompanying 2022 Warrant to purchase 0.75 shares of common stock was sold at a combined offering price of $ 42.30 .

The exercise price for the 2022 Warrants is $ 46.50 per share.

The Company received net proceeds from the 2022 Offering of approximately $ 36.9 million.

The 2022 Warrants are subject to adjustment in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Company’s common stock and also upon any distributions for no consideration of assets to the Company’s stockholders.

Each 2022 Warrant is exercisable at any time and from time to time after issuance.

In the event of certain corporate transactions, the holders of the 2022 Warrants will be entitled to receive the kind and amount of securities, cash or other property that the holders would have received had they exercised the warrants immediately prior to such transaction.

Therefore, the Company is required to account for the 2022 Warrants as liabilities and record the 2022 Warrants at fair value.

The 2022 Warrants do not entitle the holders thereof to any voting rights or any of the other rights or privileges to which holders of common stock are entitled.

“At-the-Market” Offerings

2024 Sales Agreement

“At the Market” Sales Agreement

On December 13, 2024, the Company entered into a Sales Agreement, or the Sales Agreement, with Leerink Partners to sell shares of the Company’s common stock, from time to time, through an “at the market” equity offering program under which Leerink Partners will act as sales agent.

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333-283803), filed on December 13, 2024 with the SEC and related prospectus supplement, filed on January 8, 2025 with the SEC, for aggregate gross sales proceeds of up to $ 100.0 million.

2021 Sales Agreement

On October 25, 2021, the Company entered into a Sales Agreement, or the 2021 Sales Agreement, with Leerink Partners LLC (then known as SVB Leerink LLC), or Leerink Partners, pursuant to which the Company may sell shares of the Company’s common stock, from time to time, through an “at the market” equity offering program under which Leerink Partners will act as sales agent.

The shares of common stock sold pursuant to the 2021 Sales Agreement, if any, would be issued and sold pursuant to a registration statement to be filed by the Company with the SEC, for aggregate remaining gross sales proceeds of up to $ 51.0 million.

During the years ended December 31, 2024 and 2023, the Company sold no shares of its common stock pursuant to the 2021 Sales Agreement.

The 2024 Sales Agreement supersedes the 2021 Sales Agreement, which is no longer in effect.

June 2020 Sobi Stock Purchase

On June 11, 2020, the Company entered into a stock purchase agreement with Sobi, pursuant to which the Company sold an aggregate of 180,546 shares of its common stock at a purchase price equal to $ 138.4680 per share, which represented 120 % of the 10-day volume-weighted average price of the Company’s common stock prior to signing, for aggregate gross proceeds of $ 25.0 million, or the Sobi Private Placement.

The closing of the Sobi Private Placement occurred on July 31, 2020.

In accordance with ASC 815, this forward sale treatment qualified as equity classification as the shares are not within the scope of ASC 480.

The gross proceeds of $ 25.0 million were determined to include a premium to the fair value of the Company’s shares as of July 28, 2020 of approximately $ 14.5 million.

As a result, such amount was included in the transaction price for revenue recognition of the Sobi License.

See Note 14 for details.

Also on June 11, 2020, the Company entered into a registration rights agreement, as amended by that certain letter agreement, dated as of November 4, 2020, or the Sobi Registration Rights Agreement, with Sobi, pursuant to which the Company agreed to prepare and file a registration statement with respect to the resale of the shares of common stock acquired in the Sobi Private Placement.

The Company will be required to file this resale registration statement within 30 days following receipt by the Company of a written request from Sobi to file such resale registration statement, and to have the registration statement declared effective within ten business days after the SEC informs the Company that no review of such resale registration statement will be made or that the SEC has no further comments on such resale registration statement.

December 2019 Financing

On December 18, 2019, the Company entered into a securities purchase agreement, or the 2019 Securities Purchase Agreement, with a group of institutional investors and certain members of the Board of Directors.

Pursuant to the 2019 Securities Purchase Agreement, the Company sold an aggregate of 1,254,496 shares of its common stock at a purchase price of $ 43.80 per share, warrants to purchase an aggregate of 766,275 shares of common stock at a purchase price of $ 3.75 per share underlying each common warrant, and pre-funded warrants to purchase an aggregate of 278,070 shares of common stock at a purchase price of $ 43.80 per share, all with five year terms, or the 2019 Private Placement.

The closing of the 2019 Private Placement occurred on December 23, 2019.

The exercise price of the pre-funded warrants is $ 0.003 per share and the exercise price for the common warrants is $ 43.80 per share.

In the event of a certain sale of the Company, the terms of the common warrants require us to make a payment to such common warrant holders based on a Black-Scholes valuation (using variables as specified in the warrants).

This provision does not apply to the pre-funded warrants.

Therefore, the Company is required to account for the common warrants as liabilities and record them at fair value, while the pre-funded warrants met the criteria to be classified as permanent equity.

The Company recorded the fair value of the 2019 Warrants of $ 40.7 million upon issuance using the Black-Scholes valuation model.

Issuance costs were allocated between the equity component with an offset to additional paid-in capital and the liability component recorded as expense on a relative fair value basis.

Total net proceeds from the equity offering was $ 65.6 million, after deducting transaction costs and commissions of $ 4.4 million.

As discussed in Note 6, the Company remeasured the Amended 2019 Warrants at the fair value of $ 0.8 million on December 20, 2022 and reclassified this amount to additional paid-in capital.

The outstanding 2019 Warrants expired on December 23, 2024 in accordance with their terms.

The remaining 2022 Warrants liability was revalued as of December 31, 2024 at $ 3.8 million.

During the years ended December 31, 2024 and 2023, the Company recorded a decrease of $ 2.6 million and $ 12.7 million, respectively, in the fair value of the warrants in the consolidated statements of operations and comprehensive loss.

As of December 31, 2025, no shares have been sold pursuant to the Sales Agreement.

2024 Private Placement

On July 2, 2024, the Company and the Purchasers entered into the 2024 Securities Purchase Agreement for 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 Non-Voting Convertible Preferred Stock, par value $ 0.0001 per share, or the 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.

See Note 10, “Convertible Preferred Stock.”

The following is a summary of warrant activity for the years ended December 31, 2025 and 2024:

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Outstanding at December 31, 2023 74,420 966,393 1,040,813 $ 45.98

Exercises ( 65,681 ) — ( 65,681 ) $ 43.80

Expired ( 1,928 ) ( 280,681 ) ( 282,609 ) $ 44.09

Outstanding at December 31, 2024 6,811 685,712 692,523 $ 46.96

Exercises ( 65,681 ) — ( 65,681 ) 43.80

Expired ( 251 ) — ( 251 ) $ 526.50

Outstanding at December 31, 2025 6,560 685,712 692,272 $ 46.76

During the years ended December 31, 2025 and 2024, the Company recorded a gain of $ 3.7 million and $ 2.6 million, respectively, on the change in the fair value of the warrants in the consolidated statements of operations and comprehensive loss.

On April 4, 2024, the Company implemented the Reverse Stock Split.

The Reverse Stock Split became effective at 4:30 p.m.

Eastern Time on April 4, 2024.

On April 5, 2024, the Company’s common stock began trading on The Nasdaq Global Market on a split-adjusted basis under the symbol “RNAC” with a new CUSIP number, 816212302.

As a result of the Reverse Stock Split, every 30 shares of common stock outstanding were combined, automatically and without any action on the part of the Company or its stockholders, into one share of common stock.

Stockholders entitled to fractional shares as a result of the Reverse Stock Split received a cash payment in lieu of receiving fractional shares.

The Reverse Stock Split did not change the number of authorized shares or par value of the Company’s common or preferred stock.

As of December 31, 2025, the Company had 350,000,000 shares of common stock authorized for issuance, $ 0.0001 par value per share, with 26,011,106 shares issued and outstanding.

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Reserved Shares

The Company has authorized shares of common stock for future issuance as follows:

The Company has authorized shares of common stock for future issuance as of December 31, 2025 as follows:

December 31, 2025

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Shares available for future stock incentive awards 4,148,684

Common stock options reserved for issuance

Unvested restricted stock units 522,498

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On December 9, 2020, the Board of Directors established a Stock Option Committee authorized to grant awards to certain employees and consultants subject to conditions and limitations within the 2016 Plan.

In January 2024 and 2023, the number of shares of common stock that may be issued under the 2016 Plan was increased by 215,903 and 204,056 shares, respectively.

In June 2024, the Company’s stockholders approved an amendment and restatement of the 2016 Plan to reserve an additional 3,466,544 shares of the Company’s common stock for issuance.

In January 2025, the number of shares of common stock that may be issued under the 2016 Plan was increased by 1,030,694 .

As of December 31, 2025, 3,594,407 shares remain available for future issuance under the 2016 Plan.

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The Old Cartesian Plan permits the granting of options or restricted stock to employees, officers, directors, consultants and advisors to the Company.

The unvested common stock options and Series A Preferred Stock options assumed by the Company in connection with the Merger generally vest over a four-year period.

The unvested common stock options and Series A Preferred Stock options assumed

by the Company in connection with the Merger generally vest over a four-year period.

Additionally, the stock options granted have a contractual term of ten years and only full shares can be exercised as per the individual award agreements.

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Following the Automatic Conversion, the options exercisable for shares of Series A Preferred Stock became exercisable for shares of common stock.

Settlement of Equity Compensation Awards

Upon consummation of the First Merger, the equity compensation awards of the Company outstanding as of the date of the Merger were settled as follows:

(i) each unvested option to acquire shares of common stock and each unvested restricted stock unit award with respect to shares of common stock was accelerated and vested in full at the effective time of the First Merger;

(ii) each option to acquire shares of common stock was canceled and in exchange therefore, former holders became entitled to receive an amount in cash equal to the product of (A) the total number of shares of common stock subject to the unexercised portion the stock option (determined after giving effect to the accelerated vesting) multiplied by (B) the excess, if any, of $ 61.80 , or the Cash-out Amount, over the applicable exercise price per share of common stock under such stock option;

and (iii) each restricted stock unit award with respect to shares of common stock was cancelled and the former holder of such canceled restricted stock unit became entitled, in exchange therefor, to receive an amount in cash equal to the product of (A) the total number of shares of common stock deliverable under such restricted stock unit (determined after giving effect to the accelerated vesting) multiplied by (B) the Cash-out Amount.

Stock options with an exercise price in excess of the Cash-out Amount received no cash payment.

The modification to accelerate the vesting of all awards upon the Merger resulted in full recognition of unrecognized compensation of $ 13.1 million, of which $ 5.9 million and $ 7.2 million was classified as research and development expense and general and administrative expense, respectively, in the consolidated statements of operations and comprehensive loss for the year ended December 31, 2023.

In addition, with the exception of any options with an exercise price greater than $ 61.80 per share, all awards were settled in cash for an amount equal to $ 61.80 less any exercise price associated with the awards.

The total cash payment made to the holders of stock options and restricted stock units was $ 9.4 million.

The fair value of the awards prior to the settlement was recorded to additional paid-in capital in an amount of $ 6.2 million and the amount in excess of fair value was recognized as additional stock-based compensation expense in an amount of $ 3.2 million, of which $ 1.5 million and $ 1.7 million was classified as research and development expense and general and administrative expense, respectively, in the consolidated statements of operations and comprehensive loss for the year ended December 31, 2023.

Stock-Based Compensation Expense

Stock-based compensation expense by classification included within the consolidated statements of operations and comprehensive loss, including $ 1.5 million recognized as stock-based compensation expense upon the achievement of a technical milestone by Ginkgo Bioworks Holdings, Inc., or Ginkgo, during the year ended December 31, 2023 as described in Note 16, was as follows (in thousands):

In April 2025, the Company entered into a separation agreement and release, or the Kurtoglu Separation Agreement, with the Company’s former Chief Technology Officer, Metin Kurtoglu, M.D., Ph.D.

Kurtoglu’s employment with the Company ended effective May 2025, and Dr.

Kurtoglu agreed to serve as a consultant to the Company from May 2025 through April 2026, or the Kurtoglu Consulting Period.

Pursuant to the Kurtoglu Separation Agreement, certain of Dr.

Kurtoglu’s stock options and restricted stock unit awards were modified to accelerate the vesting of a portion of the awards, continue the vesting of the remaining awards during the Kurtoglu Consulting Period, and extend the post-termination exercise period of the modified stock options.

The services performed during the Kurtoglu Consulting Period do not qualify as substantive services under ASC 718 and therefore, the continued vesting of these awards represents a modification to the original award.

The modification resulted in the recognition of $ 0.7 million compensation expense during the year ended December 31, 2025, which is reflected in research and development expenses on the consolidated statements of operations and comprehensive loss.

In October 2025, the Company entered into a separation agreement and release, or the Jewell Separation Agreement, with the Company’s former Chief Scientific Officer, Chris Jewell, Ph.D.

Jewell’s employment with the Company ended effective November 2025, and Dr.

Jewell will serve as a consultant to the Company from November 2025 to January 2026, or the Jewell Consulting Period.

Pursuant to the Jewell Separation Agreement, certain of Dr.

Jewell’s stock options and restricted stock unit awards were modified to continue the vesting of the remaining awards during the Jewell Consulting Period and extend the post-termination exercise period of the modified stock options.

The services performed during the Jewell Consulting Period do not qualify as substantive services under ASC 718 and therefore, the continued vesting of these awards represents a modification to the original award.

The modification resulted in the recognition of a reversal of $ 0.2 million in compensation expense during the year ended December 31, 2025, which is reflected in research and development expenses on the consolidated statements of operations and comprehensive loss.

Stock-based compensation expense by classification included within the consolidated statements of operations and comprehensive loss was as follows (in thousands):

Year Ended December 31,

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Stock Options

The fair value of the stock options assumed in connection with the Merger was calculated using a Black-Scholes option pricing model based on the following weighted-average assumptions:

Common Stock Series A Preferred Stock

Risk-free interest rate 4.83 % 4.92 %

Dividend yield — —

Expected term 3.59 3.29

Expected volatility 83.77 % 83.87 %

Weighted-average fair value of common stock or Series A Preferred Stock, as applicable $ 12.00 $ 403.47

The estimated grant date fair values of stock option awards granted under the 2016 Plan and the 2018 Inducement Incentive Award Plan were calculated using the Black-Scholes option pricing model based on the following weighted-average assumptions:

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The weighted average grant date fair value of stock options granted during the years ended December 31, 2025 and 2024 was $ 13.01 and $ 15.63 , respectively.

The total intrinsic value of stock options exercised during the year ended December 31, 2024 was $ 7.0 million.

No stock options were exercised during the year ended December 31, 2023.

The total intrinsic value of stock options exercised during the years ended December 31, 2025 and 2024 was $ 0.7 million and $ 7.0 million, respectively.

As of December 31, 2025, total unrecognized compensation expense related to unvested common stock options was $ 12.0 million, which is expected to be recognized over a weighted average period of 2.6 years.

The following table summarizes the stock option activity under the 2016 Plan, the 2018 Inducement Incentive Award Plan, and the Old Cartesian Plan for options for common stock:

Weighted-average

Number of remaining Aggregate

common stock Weighted-average contractual term intrinsic value

options exercise price ($) (in years) (in thousands)

Number of common stock options

Weighted-average exercise price ($)

Weighted-average remaining contractual term (in years)

Aggregate intrinsic value (in thousands)

Outstanding at December 31, 2024 1,706,035 $ 11.99 7.59 $ 12,025

Granted 1,150,259 $ 16.23

Converted from options for Series A Preferred Stock 470,403 $ 2.40

Reserved for issuance ( 7,500 ) $ 3.30

Exercised ( 90,444 ) $ 3.29

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Vested and expected to vest at December 31, 2025 2,197,439 $ 13.29 6.49 $ 2,962

The following table summarizes the stock option activity under the Old Cartesian Plan for options for Series A Preferred Stock:

Number of Weighted-average

Series A remaining Aggregate

Preferred Stock Weighted-average contractual term intrinsic value

options exercise price ($) (in years) (in thousands)

Outstanding at December 31, 2023 14,112.299 $ 79.94 5.91 $ 8,601

Converted to options for common stock ( 14,112.299 ) $ 79.94

Outstanding at December 31, 2024 — $ —

As a result of the approval of the Conversion Proposal on March 27, 2024, all conditions that could have required cash redemption of the Series A Preferred Stock underlying the stock options were removed.

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Restricted Stock Units

During the year ended December 31, 2024, the Company granted 477,037 restricted stock unit awards with a weighted average fair value of $ 19.86 per share based on the closing price of the Company’s common stock on the date of grant under the 2016 Plan and the Old Cartesian Plan, which generally vest over a four-year term.

During the year ended December 31, 2025, the Company granted 262,590 restricted stock unit awards with a weighted average fair value of $ 16.74 per share based on the closing price of the Company’s common stock on the date of grant under the 2016 Plan, which generally vest over a four-year term.

Forfeitures are estimated at the time of grant and are adjusted, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

The Company has estimated a forfeiture rate of 10 % for restricted stock unit awards based on historical experience.

The aggregate fair value of restricted stock unit awards that vested during year ended December 31, 2025 was $ 2.4 million.

No restricted stock unit awards vested during the year ended December 31, 2024.

The aggregate fair value of restricted stock unit awards that vested during the year ended December 31, 2023 was $ 0.7 million.

Unrecognized compensation expense related to the restricted stock unit awards was $ 4.9 million as of December 31, 2025, which is expected to be recognized over a weighted-average period of 2.3 years.

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Unvested at December 31, 2024

444,238 $ 19.86

Granted 262,590 $ 16.74

Vested ( 153,293 ) $ 19.86

Forfeited ( 31,037 ) $ 17.41

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Under the Astellas Agreement, the Company granted Astellas an exclusive license to the Company’s IdeXork technology arising from Xork, to develop and commercialize Xork for use in Pompe disease in combination with an Astellas gene therapy investigational or authorized product.

Xork, Genovis’ IgG Protease, was licensed pursuant to an Exclusive License Agreement, or the Genovis Agreement, with Genovis AB (publ.), or Genovis, as described in Note 16 to these consolidated financial statements.

Xork, Genovis’ IgG Protease, was licensed pursuant to an Exclusive License Agreement, or the Genovis Agreement, with Genovis AB (publ.), or Genovis, as described in Note 15, “Collaboration and License Agreements”.

Astellas paid a $ 10.0 million upfront payment to the Company upon signing of the Astellas Agreement, and the Company was entitled to receive up to $ 340.0 million in future additional payments over the course of the partnership that were contingent on the achievement of various development and regulatory milestones and, if commercialized, sales thresholds for annual net sales where Xork is used as a pre-treatment for an Astellas investigational or authorized product.

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All other development milestones would be fully constrained and would only have been included in the transaction price when the applicable milestone was deemed probable of achievement.

Each of these variable consideration items were evaluated under the most likely amount method to determine whether such amounts were probable of occurrence, or whether such amounts should have been constrained until

they became probable.

As part of its evaluation of the constraint, the Company considered numerous factors, including that receipt and timing of such development milestones was outside the control of the Company and probability of success criteria was estimated.

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The Company determined that a significant financing component did not exist in its arrangement with Astellas.

The Company also determined the options to negotiate additional fields, enter into a clinical supply agreement, and enter into a commercial supply agreement did not represent material rights under the Astellas Agreement.

The Company also determined the options to negotiate additional fields, enter into a clinical supply agreement, and

enter into a commercial supply agreement did not represent material rights under the Astellas Agreement.

Astellas had the right to terminate the Astellas Agreement in its entirety or on a field-by-field basis, upon 90 days’ written notice to the Company.

In March 2024, the Company was notified by Astellas of its intention to terminate the Astellas Agreement, which occurred effective June 6, 2024.

As of December 31, 2024, there were no unsatisfied performance obligations related to the Astellas Agreement.

As of December 31, 2023, the Company recorded $ 2.3 million as a short-term contract liability and $ 3.5 million as a long-term contract liability, representing deferred revenue associated with the Astellas Agreement.

As of December 31, 2024 and 2023, the Company recorded a receivable of $ 0.1 million and $ 0.3 million, respectively, representing billings for the Xork Development Services that were subject to reimbursement by Astellas.

As of December 31, 2025 and 2024, there were no unsatisfied performance obligations related to the Astellas Agreement.

As of December 31, 2025 the Company had no receivable balance related to the Astellas Agreement.

As of December 31, 2024, the Company recorded a receivable of $ 0.1 million, representing billings for the Xork Development Services that were subject to reimbursement by Astellas.

No revenue related to the Astellas Agreement was recognized during the year ended December 31, 2025.

Revenue of $ 6.3 million related to the Astellas Agreement was recognized during the year ended December 31, 2024, inclusive of $ 3.2 million of revenue recognized from performance obligations related to prior periods as a result of the change in transaction price during the year ended December 31, 2024.

Revenue of $ 5.5 million related to the Astellas Agreement was recognized during the year ended December 31, 2023.

Takeda Pharmaceuticals USA, Inc.

License and Development Agreement

On October 1, 2021, the Company entered into a License Agreement, or the Takeda Agreement, with Takeda Pharmaceuticals USA, Inc., or Takeda.

Under the Takeda Agreement, the Company granted Takeda an exclusive license to the Company’s ImmTOR technology initially for two specified disease indications within the field of lysosomal storage disorders.

Takeda paid a $ 3.0 million upfront payment to the Company upon signing of the Takeda Agreement, and the Company was entitled to receive up to $ 1.124 billion in future additional payments over the course of the partnership that were contingent on the achievement of development or commercial milestones or Takeda’s election to continue its activities at specified development stages.

The Company was also eligible for tiered royalties on future commercial sales of any licensed products.

Pursuant to the Takeda Agreement, the Company determined the Takeda Agreement represented a service arrangement under the scope of ASC 606, and given the reversion of the rights under the Takeda Agreement represented a penalty in substance for a termination by Takeda, the contract term would remain the stated term of the Takeda Agreement.

The Company determined that the research license, the licensed know-how, and the manufactured supply and delivery of materials represented a single promise and performance obligation to be transferred to Takeda over time due to the nature of the promises in the contract.

The delivery of the manufactured supply was the predominant promise within the arrangement, as it was essential to the utility of the licensed intellectual property.

The material supplied by the Company to Takeda was unique to the Company and cannot be obtained by other vendors.

As such, consideration in the initial transaction price was allocated to the single performance obligation and the recognition period would not extend beyond the initial contractual period.

The Company recognized the revenue associated with the upfront payment and combined single performance obligation utilizing the output method over the term that manufactured supply was delivered to Takeda.

In determining the transaction price, the Company concluded the payment associated with all the performance milestones was fully constrained and only included in the transaction price when the respective milestone was deemed probable of achievement.

As part of its evaluation of the constraint, the Company considered numerous factors, including that receipt and timing of such study milestones is outside the control of the Company and probability of success criteria is estimated.

The Company re-evaluated the transaction price in each reporting period, as uncertain events were resolved, or as other changes in circumstances occurred.

Takeda had the right to exercise covenant release rights on a field-by-field basis.

If Takeda exercised its covenant release rights, the Company could have received exercise payments per indication and would have been entitled to significant development and commercial milestone payments and tiered royalties on commercial sales.

The Company determined that a significant financing component did not exist in its arrangement with Takeda.

The Company also determined the options to negotiate additional fields, pursue other products, enter into a supply agreement explore additional fields, and pursue additional development under the initial fields did not represent material rights under the agreement.

Takeda had the right to terminate the Takeda Agreement in its entirety or on a field-by-field basis, upon 90 days’ written notice to the Company.

On March 9, 2023, the Company was notified by Takeda of the achievement of the milestone event related to the completion of a non-clinical milestone for one of the specified disease indications within the field of lysosomal storage

disorders under the Takeda Agreement.

Accordingly, the Company received a milestone payment of $ 0.5 million during the year ended December 31, 2023.

The Takeda Agreement was terminated effective July 25, 2023, following Takeda’s decision to discontinue discovery and preclinical activities in adeno-associated virus, or AAV, gene therapy.

As of December 31, 2024 and 2023, there were no unsatisfied performance obligations related to the Takeda Agreement.

No revenue and revenue of $ 0.6 million related to the Takeda Agreement was recognized during the years ended December 31, 2024 and 2023, respectively.

Swedish Orphan Biovitrum AB (publ.)

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On June 11, 2020, the Company and Sobi entered into a License and Development Agreement.

Pursuant to the Sobi License, the Company agreed to grant Sobi an exclusive, worldwide (except as to Greater China) license to develop, manufacture and commercialize the SEL-212 drug candidate, which is currently in development for the treatment of chronic refractory gout.

The SEL-212 drug candidate is a pharmaceutical composition containing a combination of SEL-037, or the Compound, and ImmTOR.

Pursuant to the Sobi License, the Company agreed to grant Sobi an exclusive, worldwide (except as to Greater China) license to develop, manufacture and commercialize the NASP drug candidate, which is currently in development for the treatment of chronic refractory gout.

The NASP drug candidate is a pharmaceutical composition containing a combination of SEL-037, or the Compound, and ImmTOR.

Pursuant to the Sobi License, in consideration of the license, Sobi agreed to pay the Company a one-time, upfront payment of $ 75.0 million.

Sobi has also agreed to make milestone payments totaling up to $ 630.0 million to the Company upon the achievement of various development and regulatory milestones and, if commercialized, sales thresholds for annual net sales of SEL-212, 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 also agreed to make milestone payments totaling up to $ 630.0 million to the Company upon the achievement of various development and regulatory milestones and, if commercialized, 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.

Any proceeds received from milestone payments or royalties relating to the Sobi License would be required to be distributed to holders of CVRs, net of certain deductions.

Pursuant to the Sobi License, the Company agreed to supply (at cost) quantities of the Compound and ImmTOR as necessary for completion of the two Phase 3 clinical trials of SEL-212 (DISSOLVE I and DISSOLVE II) and a six-month placebo extension.

Pursuant to the Sobi License, the Company agreed to supply (at cost) quantities of the Compound and ImmTOR as necessary for completion of the two Phase 3 clinical trials of NASP (DISSOLVE I and DISSOLVE II) and a six-month placebo extension.

The Company was required to supply quantities of the Compound until all rights to the Compound and any materials needed to manufacture the Compound were transferred to Sobi, which transfer occurred upon the execution of Amendment No.

1 to the License and Development Agreement on October 31, 2023.

Sobi has agreed to reimburse the Company for all budgeted costs incurred to complete development of SEL-212, including but not limited to costs incurred while conducting and completing the Phase 3 DISSOLVE trials, except for any costs of additional development activities required that are related to ImmTOR and that are unrelated to SEL-212.

Sobi will have control and responsibility over all regulatory filings, including any investigational drug applications (IND), biologics license applications (BLA), and marketing authorization applications (MAA) relating to the licensed product.

Sobi has agreed to reimburse the Company for all budgeted costs incurred to complete development of NASP, including but not limited to costs incurred while conducting and completing the Phase 3 DISSOLVE trials, except for any costs of additional development activities required that are related to ImmTOR and that are unrelated to NASP.

Sobi will have control and responsibility over all regulatory filings, including any investigational drug applications, or IND, biologics license applications, or BLA, and marketing authorization applications, or MAA relating to the licensed product.

The transactions contemplated by the Sobi License were consummated on July 28, 2020.

Sobi may terminate the Sobi License for any reason upon 180 days’ written notice to the Company, whereby all rights granted under the Sobi License would revert back to the Company.

In addition, if Sobi were to terminate the Sobi License, the Company has the option to obtain a license to all patents and know-how necessary to exploit SEL-212 in existence as of the termination date from Sobi in return for making an equitable royalty payment to Sobi.

Additionally, on June 11, 2020, the Company entered into the Sobi Purchase Agreement in connection with the Sobi License.

The closing of the Sobi Private Placement occurred on July 31, 2020, following the closing of the transactions contemplated under the Sobi License.

See Note 12 for details.

In addition, if Sobi were to terminate the Sobi License, the Company has the option to obtain a license to all patents and know-how necessary to exploit NASP in existence as of the termination date from Sobi in return for making an equitable royalty payment to Sobi.

The Company determined that the Sobi License represents a service arrangement under the scope of ASC 606.

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Given the reversion of the rights under the Sobi License represents a penalty in substance for a termination by Sobi, the contract term would remain the stated term of the Sobi License.

The Company determined that the Sobi License contained three distinct performance obligations due to the nature of the promises in the contract, which includes conducting the Phase 3 DISSOLVE trials, Sobi’s option to set-up a second source supplier, and a combined obligation comprised of the delivery of the license to SEL-212, transfer of the know-how and the manufacturing and delivery of SEL-212 supply for development, or the Combined License Obligation.

As the set-up of a second source supplier was optional for Sobi and the Company was to be reimbursed at cost for its efforts in the subsequent set-up and technology transfer, the option for this future service was determined to be at a significant and incremental discount to its standalone selling price and treated as a material right in the arrangement, namely a distinct performance obligation.

In determining the transaction price, the Company concluded the upfront payment of $ 75.0 million and the $ 5.0 million development milestone associated with the dosing of the first patient in the Phase 3 DISSOLVE trials were included in the

transaction price.

The Company determined that the Sobi License contained three distinct performance obligations due to the nature of the promises in the contract, which includes conducting the Phase 3 DISSOLVE trials, Sobi’s option to set-up a second source supplier, and a combined obligation comprised of the delivery of the license to NASP, transfer of the know-how and the manufacturing and delivery of NASP supply for development, or the Combined License Obligation.

As the set-up of a second source supplier was optional for Sobi and the Company was to be reimbursed at cost for its efforts in the subsequent set-up and

technology transfer, the option for this future service was determined to be at a significant and incremental discount to its standalone selling price and treated as a material right in the arrangement, namely a distinct performance obligation.

All other development milestones will be fully constrained and only be included in the transaction price when the respective milestone is deemed probable of achievement.

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As the Company was to provide the set-up and technology transfer services and the future supply at cost, the discount of the option was equal to the margin amount.

The Company considered discussions with Sobi as well as probability of regulatory success of SEL-212 in determining the likelihood of exercise.

The Company considered discussions with Sobi as well as probability of regulatory success of NASP in determining the likelihood of exercise.

The Company estimated the standalone selling price of the Combined License Obligation by utilizing a discounted cash flow model.

10 unchanged sentences

On October 31, 2023, the Company and Sobi entered into Amendment No.

1 to the License and Development Agreement, pursuant to which the Company granted Sobi an exclusive license to manufacture ImmTOR solely in connection with Sobi’s development of SEL-212 under the License and Development Agreement and transferred certain contracts and manufacturing equipment to Sobi.

1 to the License and Development Agreement, pursuant to which the Company granted Sobi an exclusive license to manufacture ImmTOR solely in connection with Sobi’s development of NASP under the License and Development Agreement and transferred certain contracts and manufacturing equipment to Sobi.

Additionally, Sobi’s option to set-up a second source supplier was removed as a result of the amendment.

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The Company maintains no responsibilities to Sobi to manufacture, or supply Sobi with, ImmTOR under the Sobi License.

On June 28, 2024, Sobi initiated a rolling biologics license application to the FDA for SEL-212 for the potential treatment of chronic refractory gout which resulted in the achievement of a development milestone and a $ 30.0 million payment obligation from Sobi to the Company.

On June 28, 2024, Sobi initiated a rolling biologics license application to the FDA for NASP for the potential treatment of chronic refractory gout which resulted in the achievement of a development milestone and a $ 30.0 million payment obligation from Sobi to the Company.

As a result, the development milestone was no longer constrained and $ 30.0 million was recognized as revenue during the year ended December 31, 2024 as there were no remaining performance obligations under the Sobi License.

The proceeds from the achievement of the development milestone were received from Sobi in July 2024 and are expected to be included, net of deductions as specified in the CVR Agreement, in the next scheduled distribution to holders of the CVRs in March 2025.

As of December 31, 2024 and 2023, the Company recorded a total outstanding receivable of $ 0.1 million and $ 4.6 million, respectively, representing billings for the Phase 3 DISSOLVE program that are subject to reimbursement by Sobi.

Additionally, as of December 31, 2023, the Company recorded a total unbilled receivable of $ 3.0 million representing revenue earned but not yet billed for the Phase 3 DISSOLVE program.

As of December 31, 2024, there was no unbilled receivable outstanding.

Revenue of $ 31.9 million, inclusive of the $ 30.0 million development milestone, related to the Sobi License was

recognized during the year ended December 31, 2024, and $ 1.9 million of revenue recognized from performance obligations related to prior periods as a result of the change in transaction price during the year ended December 31, 2024.

Revenue of $ 19.4 million related to the Sobi License was recognized during the year ended December 31, 2023, inclusive of $ 1.1 million of revenue recognized from performance obligations related to prior periods as a result of the change in transaction price during the year ended December 31, 2023.

Sarepta Therapeutics, Inc.

Research License and Option Agreement

In June 2020, the Company and Sarepta Therapeutics, Inc., or Sarepta, entered into a Research License and Option Agreement, or the Sarepta Agreement.

Pursuant to the Sarepta Agreement, the Company agreed to grant Sarepta a license under the Company’s intellectual property rights covering the Company’s antigen-specific biodegradable nanoparticle encapsulating ImmTOR to research and evaluate ImmTOR in combination with Sarepta’s adeno-associated virus gene therapy technology, or gene editing technology, using viral or non-viral delivery, to treat Duchenne Muscular Dystrophy and certain Limb-Girdle Muscular Dystrophy subtypes, or the Indications.

Sarepta initially had an option term of 24 months during which it could opt-in to obtain an exclusive license to further develop and commercialize the product to treat at least one Indication, with a potential to extend the option term for an additional fee.

The Company agreed to supply ImmTOR to Sarepta for clinical supply on a cost-plus basis under the Sarepta Agreement.

Sarepta paid a $ 2.0 million upfront payment to the Company upon signing of the Sarepta Agreement, and the Company was eligible to receive additional preclinical payments during the option term.

If Sarepta opted in to an exclusive license agreement, the Company could have received option exercise payments per Indication upon execution of the exclusive license, and the Company would have been entitled to significant development and commercial milestone payments and tiered royalties ranging from the mid-to-high single digits based on net sales.

Pursuant to the Sarepta Agreement, the Company determined the Sarepta Agreement represented a service arrangement under the scope of ASC 606, with a 24 -month contract duration.

Given the reversion of the rights under the Sarepta Agreement represents a penalty in substance for a termination by Sarepta, the contract term would remain the stated term of the Sarepta Agreement.

The Company determined that the Sarepta Agreement and supply obligation including the delivery of the research license, the licensed know-how, the manufactured supply and delivery of materials represented a single promise and performance obligation to be transferred to Sarepta over time due to the nature of the promises in the contract.

The delivery of the manufactured supply was the predominant promise within the arrangement, as it was essential to the utility of the licensed intellectual property.

As such, consideration in the initial transaction price was allocated to the single performance obligation based on the contractual price.

In determining the transaction price, the Company concluded the payment associated with all the performance milestones was fully constrained and would only be included in the transaction price when the respective milestone was deemed probable of achievement.

Each of these variable consideration items was evaluated under the most likely amount method to determine whether such amounts were probable of occurrence, or whether such amounts should have been constrained until they became probable.

As part of its evaluation of the constraint, the Company considered numerous factors, including that receipt of such study milestones was outside the control of the Company and probability of success criteria was estimated.

The Company also determined the option to enter into a future commercial license agreement and extend the term of the option did not represent a material right since it was not priced at an incremental discount.

Sarepta had the right to terminate the Sarepta Agreement for any reason upon 30 days’ written notice to the Company.

The Sarepta Agreement contained other customary terms and conditions, including representations and warranties, covenants, termination, and indemnification obligations in favor of each party.

On April 13, 2021, the Company was notified by Sarepta of the achievement of the milestone event related to the completion of a non-clinical study for Duchenne muscular dystrophy and certain limb-girdle muscular dystrophies under the Sarepta Agreement.

Accordingly, the Company received a milestone payment of $ 3.0 million during the three months ended June 30, 2021.

On June 10, 2022, the Company was notified by Sarepta that Sarepta would be extending their options under the Sarepta Agreement.

In exchange for a nine-month extension to Sarepta’s options to both Duchenne muscular dystrophy and certain limb-girdle muscular dystrophies, the Company received a milestone payment of $ 2.0 million during the year ended December 31, 2022.

On June 15, 2022, the Company was notified by Sarepta of the achievement of a milestone event related to certain preclinical study milestones under the Sarepta Agreement.

Accordingly, the Company received a milestone payment of $ 4.0 million during the year ended December 31, 2022.

On March 13, 2023, the Company was notified by Sarepta that Sarepta would not be exercising its exclusive option under the Sarepta Agreement.

The Sarepta Agreement terminated upon the expiration of the option in March 2023.

As of December 31, 2024 and 2023, there were no unsatisfied performance obligations related to the Sarepta Agreement.

No revenue and revenue of $ 0.5 million related to the Sarepta Agreement was recognized during the years ended December 31, 2024 and 2023, respectively.

The proceeds from the achievement of the development milestone were received from Sobi in July 2024 and are were included, net of deductions as specified in the CVR Agreement, in the distribution to holders of the CVRs in March 2025.

As of December 31, 2025 and 2024, the Company recorded a total outstanding receivable of $ 0.1 million, representing billings for the Phase 3 DISSOLVE program that are subject to reimbursement by Sobi.

As of December 31, 2025 and 2024, there was no unbilled receivable outstanding.

No revenue related to the Sobi License was recognized during the year ended December 31, 2025.

Revenue of $ 31.9 million, inclusive of the $ 30.0 million development milestone, related to the Sobi License was recognized during the year ended December 31, 2024, and $ 1.9 million of revenue recognized from performance obligations related to prior periods as a result of the change in transaction price during the year ended December 31, 2024.

Transaction Price Allocated to Future Performance Obligations

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As of December 31, 2025, there were no unsatisfied performance obligations from contracts with customers.

Contract Balances from Contracts with Customers

The following table presents changes in the Company’s contract liabilities during the year ended December 31, 2024 (in thousands):

Balance at Balance at

beginning of period Additions Deductions end of period

Contract liabilities:

Deferred revenue $ 5,849 $ — $ ( 5,849 ) $ —

Total contract liabilities $ 5,849 $ — $ ( 5,849 ) $ —

Grant revenue

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In June 2024, the Company received funding approval from the National Institute of Neurological Disorders and Stroke of the National Institutes of Health, or NINDS, for an award of $ 1.5 million granted for the budget period, which runs from June 2024 through May 2025.

Subject to the availability of funds and satisfactory progress of the project, an additional $ 1.5 million has been recommended by NINDS to be awarded for the budget period June 2025 through May 2026.

The initial $ 1.5 million funding was provided by NINDS to further the Company’s use of RNA-based CAR-T cells to combat autoantibody-associated autoimmune disorders.

In June 2025, the Company received funding approval from NINDS for an additional award of $ 1.5 million granted for the budget period June 2025 through May 2026.

The funding was provided by NINDS to further the Company’s use of RNA-based CAR-T cells to combat autoantibody-associated autoimmune disorders.

Grant funding is to be used solely for manufacturing of RNA-based CAR-T cells and analysis of samples to inform mechanism of action.

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The Company will recognize grant revenue when expenses reimbursable under the grant have been incurred.

As of December 31, 2024, the Company recorded a receivable of $ 0.6 million that is subject to reimbursement by NINDS.

Accordingly, the Company recognized grant revenue of $ 0.6 million during the year ended December 31, 2024.

As of December 31, 2025 and 2024, the Company recorded a receivable of $ 0.9 million and $ 0.6 million, respectively, that are subject to reimbursement by NINDS.

The Company recognized grant revenue of $ 2.3 million and $ 0.6 million during the years ended December 31, 2025 and 2024, respectively.

Related-Party Transactions

1 unchanged sentence

On July 2, 2024, the Company entered into the 2024 Securities Purchase Agreement with the Purchasers.

The Purchasers included (i) Dr.

Springer, a member of the Company’s Board of Directors;

(ii) TAS Partners LLC, an affiliate of Dr.

Springer, and (iii) Dr.

Chafen Lu, Dr.

Springer’s wife (see Note 11).

The Purchasers included (i) Timothy A.

Springer, Ph.D., a member of the Company’s Board of Directors, (ii) TAS Partners LLC, an affiliate of Dr.

Springer, and (iii) Chafen Lu, Ph.D., Dr.

Springer’s wife (see Note 11 “Equity”).

The below issuances and sales to related parties of the Company were made during the year ended December 31, 2024.

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2023 Securities Purchase Agreement

On November 13, 2023, the Company entered into the 2023 Securities Purchase Agreement with (i) Dr.

Springer, (ii) TAS Partners LLC, and (iii) Seven One Eight Three Four Irrevocable Trust, a trust associated with Dr.

Murat Kalayoglu, in which the Company agreed to issue and sell an aggregate of 149,330.115 shares of Series A Preferred Stock for an aggregate purchase price of $ 60.25 million (see Note 11).

On November 13, 2023, the Company entered into the 2023 Securities Purchase Agreement with (i) Timothy A.

Springer, Ph.D., (ii) TAS Partners LLC, and (iii) Seven One Eight Three Four Irrevocable Trust, a trust associated with Murat Kalayoglu, M.D., Ph.D., in which the Company agreed to issue and sell an aggregate of 149,330.115 shares of Series A Preferred Stock for an aggregate purchase price of $ 60.25 million (see Note 11 “Equity”).

The 2023 Private Placement included a delayed settlement mechanism, and as a result, the below issuances and sales to related parties of the Company were made during the year ended December 31, 2024.

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99,140.326 $ 40,000

The below issuances and sales to related parties of the Company were made subject to the 2023 Private Placement during the year ended December 31, 2023.

Name Shares of Series A Preferred Stock purchased Total aggregate purchase price

(in thousands)

Springer, Ph.D.

24,785.081 $ 10,000

TAS Partners LLC (affiliate of Timothy A.

Springer, Ph.D.) 24,785.081 $ 10,000

Seven One Eight Three Four Irrevocable Trust (affiliate of Murat Kalayoglu, MD, Ph.D.) 619.627 $ 250

Exercise of Amended 2019 Warrants

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Under the NCI Agreement, the Company must use reasonable commercial efforts to bring licensed products and licensed processes to the point of Practical Application (as defined in the NCI Agreement).

Upon the Company’s first commercial sale,

the Company must use reasonable commercial efforts to make licensed products and licensed processes reasonably accessible to the United States public.

Upon the Company’s first commercial sale, the Company must use reasonable commercial efforts to make licensed products and licensed processes reasonably accessible to the United States public.

After the Company’s first commercial sale, the Company must make reasonable quantities of licensed products or materials produced via licensed processes available to patient assistance programs and develop educational materials detailing the licensed products.

Unless the Company obtains a waiver from NCI, the Company must have licensed products and licensed processes manufactured substantially in the United States.

Prior to the first commercial sale, upon NCI’s request, the Company is obligated to provide NCI with commercially reasonable quantities of licensed products made through licensed processes to be used for in vitro research.

Additionally, the Company must use reasonable commercial efforts to initiate a Phase 3 clinical trial of a licensed product by the fourth quarter of 2024, submit a BLA with respect to a licensed product by the fourth quarter of 2026, and make a first commercial sale of a licensed product by the fourth quarter of 2028.

Prior to the first commercial sale, upon NCI’s

request, the Company is obligated to provide NCI with commercially reasonable quantities of licensed products made through licensed processes to be used for in vitro research.

Additionally, the Company must use reasonable commercial efforts to submit a BLA with respect to a licensed product by the fourth quarter of 2026 and make a first commercial sale of a licensed product by the fourth quarter of 2028.

The NCI Agreement terminates upon the expiration of the last to expire of the patent rights licensed thereunder, if not sooner terminated.

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The Company agreed to indemnify NCI against any liability arising out of the Company’s, sublicensees’ or third-parties’ use of the licensed patent rights and licensed products or licensed processes developed in connection with the licensed patent rights.

Ginkgo Bioworks Holdings, Inc.

Collaboration and License Agreements

On October 25, 2021, the Company entered into a Collaboration and License Agreement, or the First Ginkgo Agreement, with Ginkgo.

Under the First Ginkgo Agreement, Ginkgo will design next generation IgA proteases with potentially transformative therapeutic potential.

In return, Ginkgo is eligible to earn both upfront research and development fees and milestone payments, including certain milestone payments for fixed fair values in the form of the Company’s common stock, clinical and commercial milestone payments of up to $ 85.0 million in cash.

The First Ginkgo Agreement was assessed for collaboration components and was determined not to be within the scope of ASC 808 as the risk and rewards are not shared by both parties.

The Company will expense costs related to the First Ginkgo Agreement as incurred until regulatory approval is received in accordance with ASC 730.

The Company is accounting for the contingently issuable shares to be issued in exchange for the license obtained from Ginkgo as a liability classified stock-based compensation arrangement with a non-employee which will be recognized when achievement of the milestones is probable.

The Company will assess the capitalization of costs incurred after the receipt of regulatory approval and, if applicable, will amortize these payments based on the expected useful life of each asset, typically based on the expected commercial exclusivity period.

The Company is also obligated to pay Ginkgo tiered royalties ranging from low-single digit to high-single digit percentages of annual net sales of collaboration products which will be expensed as the commercial sales occur.

On January 3, 2022, the Company entered into a Collaboration and License Agreement, or the Second Ginkgo Agreement, with Ginkgo.

Under this agreement, the Company will engage with Ginkgo to develop AAV capsids designed to enhance transduction efficiency and transgene expression.

In return, Ginkgo is eligible to earn both upfront research and development fees and milestone payments, including certain milestone payments in the form of shares of the Company’s common stock, clinical and commercial milestone payments of up to $ 207 million in cash.

The Second Ginkgo Agreement was assessed for collaboration components and was determined not to be within the scope of ASC 808 as the risk and rewards are not shared by both parties.

The Company will expense costs related to the Second Ginkgo Agreement as incurred until regulatory approval is received in accordance with ASC 730.

The Company is accounting for the contingently issuable shares of common stock to be issued in exchange for the license obtained from Ginkgo as a liability-classified, stock-based compensation arrangement with a non-employee which will be recognized when achievement of the milestones is probable.

On June 13, 2022, the Company was notified of the achievement of the midpoint of the technical development plan under the First Ginkgo Agreement by Ginkgo.

This milestone resulted in the payment of $ 0.5 million and issuance of 29,761 shares of the Company’s common stock then-valued at $ 1.0 million to Ginkgo during the year ended December 31, 2022.

On July 19, 2023, the Company and Ginkgo mutually agreed that the completion of the technical development plan’s midpoint task under the Second Ginkgo Agreement had been achieved as of June 30, 2023.

This milestone resulted in the payment of $ 1.0 million and issuance of 44,642 shares of the Company’s common stock then-valued at $ 1.5 million to Ginkgo during the year ended December 31, 2023.

Genovis AB (publ.)

8 unchanged sentences

In February 2023, the Company made a $ 4.0 million payment to Genovis as a result of the sublicense of Xork to Astellas.

See Note 14 to these consolidated financial statements for further discussion on the Astellas Agreement.

See Note 13, “Revenue Arrangements” to these consolidated financial statements for further discussion on the Astellas Agreement.

In March 2024, the Company notified Genovis of its intention to terminate the Genovis Agreement, which occurred effective September 13, 2024.

Cyrus Biotechnology, Inc.

Collaboration and License Agreement

On September 7, 2021, the Company and Cyrus Biotechnology, Inc., or Cyrus, entered into a collaboration and license agreement, or the Cyrus Agreement.

Pursuant to the Cyrus Agreement, Cyrus agreed to grant the Company an exclusive, worldwide license to certain intellectual property to form a protein engineering collaboration combining the Company’s ImmTOR platform with Cyrus’ ability to redesign protein therapeutics.

The lead program was a proprietary interleukin-2, or IL-2, protein agonist designed to selectively promote expansion of regulatory T cells for treatment of patients with autoimmune diseases and other deleterious immune conditions.

In return for the licensed intellectual property, the Company made an upfront payment and was obligated to pay certain discovery, development, and sales-based milestones which could have potentially totaled up to approximately $ 1.5 billion across multiple programs.

The Cyrus Agreement was assessed for collaboration components and was determined not to be within the scope of ASC 808 as the risk and rewards are not shared by both parties.

The Company expensed costs related to the Cyrus Agreement as incurred until regulatory approval is received in accordance with ASC 730.

The Company assessed the capitalization of costs incurred after the receipt of regulatory approval and, if applicable, would have amortized these payments based on the expected useful life of each asset, typically based on the expected commercial exclusivity period.

The Company was also obligated to pay Cyrus tiered royalties ranging from mid-single digit to low-double digit percentages of annual net sales of collaboration products which would have been expensed as commercial sales occur.

On June 13, 2022, the Company and Cyrus mutually agreed that the preclinical key in-vitro success milestone had been achieved.

In October 2023, the Company notified Cyrus of its termination of the Cyrus Agreement, effective December 29, 2023.

Stock Purchase Agreement

Additionally, on September 7, 2021, the Company entered into a stock purchase agreement, or the Series B Preferred Stock Purchase Agreement, in connection with the Cyrus Agreement.

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 has recognized the $ 2.0 million investment of Cyrus’ Series B Preferred Stock at cost on the purchase date.

As of December 31, 2024, no impairment indicators are present and there were no observable price changes.

Therefore, the carrying value of the investment in Cyrus is $ 2.0 million on the accompanying consolidated balance sheets.

The Company’s maximum exposure to loss related to this VIE is limited to the carrying value of the investment.

The Company has not provided financing to Cyrus other than the amount contractually required by the Series B Preferred Stock Purchase Agreement.

Asklepios Biopharmaceutical, Inc.

Feasibility Study and License Agreement

In August 2019, the Company entered into a feasibility study and license agreement, or the AskBio Collaboration Agreement, with Asklepios Biopharmaceutical, Inc., or AskBio.

Pursuant to the AskBio Collaboration Agreement, the Company and AskBio agreed to license intellectual property rights to each other as part of a collaboration to research, develop, and commercialize certain AAV gene therapy products utilizing the Company’s ImmTOR platform to enable re-dosing of such AAV gene therapy products to treat serious rare and orphan genetic diseases for which there is a significant unmet medical need.

Pursuant to the AskBio Collaboration Agreement, the Company and AskBio agreed to conduct proof of concept studies to potentially validate the use of ImmTOR in conjunction with AskBio’s AAV gene therapy, or SEL-302, (previously disclosed as MMA-101, in combination with ImmTOR) for the treatment of methylmalonic acidemia, or MMA, to mitigate the formation of neutralizing anti-AAV capsid antibodies.

On April 29, 2021, the Company was notified by AskBio that it intended to opt-out of development of the MMA indication.

The Company and AskBio shared responsibility for the research, development and commercialization of products developed under the SEL-399 program collaboration.

The parties also shared research, development, and commercialization costs equally for all collaboration products, but with a right of either party to opt out of certain products, and thereby not be required to share costs for such products.

Each party would have received a percentage of net profits under the collaboration equal to the percentage of shared costs borne by such party in the development of such product.

Pursuant to the AskBio Collaboration Agreement, AskBio was responsible for manufacturing the AAV capsids and AAV vectors and the Company was responsible for manufacturing ImmTOR.

The Company and AskBio mutually agreed to the termination of the AskBio Collaboration Agreement, effective December 13, 2023.

For the years ended December 31, 2024 and 2023, the Company recognized no and $ 0.1 million, respectively, of collaboration expense under the AskBio Collaboration Agreement in which actual costs incurred by both parties approximate a 50 % cost share.

Shenyang Sunshine Pharmaceutical Co., Ltd

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In accordance with ASC 805-740-25-3, recognition of deferred tax assets and liabilities is required for substantially all temporary differences and acquired tax carryforwards and credits.

The Company has computed estimated temporary differences and acquired tax carryforwards and credits as of the transaction date.

The Company will not have tax basis in IPR&D booked as part of the purchase accounting.

The Company does not have a tax basis in IPR&D booked as part of the purchase accounting.

For accounting purposes, the IPR&D will not be amortized and only subject to impairment review and testing.

Though the tax effects may be delayed indefinitely, ASC 740-10-55-63 states that “deferred tax liabilities may not be eliminated or reduced because a reporting entity may be able to delay the settlement of those liabilities by delaying the events that would cause taxable temporary differences to reverse.” The Company can potentially only utilize indefinite-lived assets as it relates to this indefinite lived intangible deferred tax liability reversal.

As such, the Company has booked a deferred tax liability for the portion of the liability that cannot be reduced based on scheduling.

Additionally, a portion of this target deferred tax liability is offset with the Company’s pre-Merger deferred tax assets on a combined basis, and as such the portion of deferred tax liability reduced by the Company’s pre-Merger deferred tax assets has been charged to income rather than to goodwill.

For the year ended December 31, 2024, the Company recognized a current tax expense of $ 0.3 million.

The Company can potentially only utilize indefinite-lived assets as it relates to this indefinite lived intangible deferred tax liability reversal.

As such, the Company booked a deferred tax liability for the portion of the liability that cannot be reduced based on scheduling through the year ended December 31, 2025.

For the year ended December 31, 2025, the Company recognized a current tax benefit of $ 9.2 million.

The following table reconciles the federal statutory income tax rate to the Company’s effective income tax rate:

For the year ended December 31, 2024, the Company recognized a current tax expense of $ 0.3 million.

The components of the benefit (expense) for income taxes for the years ended December 31, 2025 and 2024 consisted of the following (in thousands):

Year Ended December 31,

Statutory U.S.

State 8,622 ( 384 )

Total deferred

9,193 ( 287 )

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

The following table reconciles the federal statutory income tax rate to the Company’s effective income tax rate after applying ASU 2023-09 prospectively for the year ended December 31, 2025 (in thousands, except for percentages):

Year Ended December 31, 2025

Expected tax benefit $ 29,256 21.0 %

Nontaxable or nondeductible items 203 0.1 %

State and local taxes, net of federal benefit 3,206 2.3 %

Effect of changes in tax laws or rates enacted in the current period 3,604 2.6 %

Change in valuation allowance, net ( 31,573 ) ( 22.6 ) %

Orphan drug credits 3,959 2.8 %

Research tax credits 892 0.6 %

Other reconciling items:

Change in fair value of the CVR liability ( 714 ) ( 0.5 ) %

Other 360 0.3 %

Income tax benefit (expense) $ 9,193 6.6 %

The following table reconciles the federal statutory income tax rate to the Company’s effective income tax rate prior to the adoption of ASU 2023-09 for the year ended December 31, 2024:

Year Ended December 31, 2024

Statutory U.S.

State income taxes - net of federal benefit

Permanent items

1.0 % ( 1.6 ) %

Research tax credits 0.3 %

Change in fair value of contingent value right liability

Change in fair value of the CVR liability 127.9 %

Change in fair value of forward contract liabilities ( 1.9 ) %

( 1.9 ) % ( 13.2 ) %

Valuation allowance, net

( 160.1 ) % 2.8 %

Stock-based compensation

0.9 % ( 3.9 ) %

Effective income tax rate

( 0.4 ) % 8.0 %

The tax effects of temporary differences that give rise to the Company’s net deferred tax assets are as follows (in thousands):

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Stock-based compensation expense 2,601 1,070

Other expenses — 705

Patent and license costs 8,340 8,540

Deferred revenue 80,769 75,567

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Contingent value right liability 115,330 108,832

R&E Capitalization 26,863 19,778

Patent and license costs 8,540 9,140

Research & experimental expenditure capitalization

36,820 26,863

Other expenses 588 —

Gross deferred tax assets $ 319,800 $ 274,806

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Valuation allowance ( 296,910 ) ( 247,867 )

Net deferred tax assets/(liabilities) $ ( 16,140 ) $ ( 15,853 )

Net deferred tax liabilities

$ ( 6,948 ) $ ( 16,140 )

The Company has provided a full valuation allowance against its net deferred tax assets, outside of the indefinite tax liability booked as part of the Merger.

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The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets and concluded that it is more likely than not that the Company will not realize the benefit of its net deferred tax assets.

The valuation allowance increased by $ 123.6 million for the year ended December 31, 2024, primarily as a result of tax loss in the current year and the recognition of a $ 108.8 million tax benefit related to the Company’s CVR liability.

The valuation allowance decreased by $ 3.5 million for the year ended December 31, 2023, primarily as a result of a tax benefit booked as part of the Merger.

As of December 31, 2024, the Company is in the process of winding down operations in Russia and does not expect any tax liability relating to such operations.

At December 31, 2024, the Company has federal net operating loss carryforward of $ 152.6 million, which can be carried forward indefinitely, subject to an 80% limitation and state net operating loss carryforward of $ 187.8 million, of which $ 74.4 million has an unlimited carryforward and the remaining $ 113.4 million will expire at various times through 2044.

The valuation allowance increased by $ 49.0 million for the year ended December 31, 2025, primarily as a result of tax loss and an increase in research and experimental, or R&E, expenditure capitalization in the current year.

The valuation allowance increased by $ 123.6 million for the year ended December 31, 2024, primarily as a result of tax loss in the current year and a tax benefit determined in the year for the Company’s CVR liability.

At December 31, 2025, the Company has federal net operating loss, or NOL, carryforward of $ 209.0 million, which can be carried forward indefinitely, subject to an 80% limitation and state net operating loss carryforward of $ 265.2 million, of which $ 128.6 million has an unlimited carryforward, subject to an 80% limitation, and the remaining $ 136.6 million will expire at various times through 2045.

The Company has $ 10.0 million and $ 0.9 million, respectively, of federal and state research and development tax credit carryforwards, which will expire at various times through 2045.

Utilization of the NOL carryforwards and research and orphan drug credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, and similar state law due to ownership changes that could occur in the future.

Utilization of the NOL carryforwards

and research and orphan drug credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, and similar state law due to ownership changes that could occur in the future.

These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income.

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As of the adoption date on January 1, 2010 and through December 31, 2025, the Company had no unrecognized tax benefits or related interest and penalties accrued.

As of December 31, 2024, the Company has not completed a detailed study of its research and development and orphan drug credits for the tax years ending December 31, 2023 and December 31, 2024 .

As of December 31, 2025, the Company has not completed a detailed study of its research and development and orphan drug credits for the tax years ending December 31, 2023 through December 31, 2025 .

As a result, the Company will adjust its deferred tax asset balances and include the impacts in the research tax credits and state income taxes – net of federal benefit lines in the effective rate reconciliation next year, once the updated study has been completed.

The Tax Cuts and Jobs Act requires taxpayers to capitalize and amortize, rather than deduct, research and experimental, or R&E, expenditures under Section 174 for tax years beginning after December 31, 2021.

These rules became effective for the Company during the year ended December 31, 2022.

As a result, the Company has capitalized R&E costs of $ 45.1 million and $ 43.9 million for the years ended December 31, 2024 and December 31, 2023, respectively.

The Company will amortize these costs for tax purposes over five years if the R&E was performed in the United States and over 15 years if the R&E was performed outside the United States.

Interest and penalty charges, if any, related to unrecognized tax benefits would be classified as income tax expense in the accompanying statement of operations.

On July 4, 2025, the One Big Beautiful Bill Act, or OBBBA, was enacted.

The OBBBA amends U.S.

tax law including provisions related to domestic R&E expenses and bonus depreciation, among others.

The provision related to domestic R&E allows for immediate expensing of domestic R&E costs along with accelerated deductions on previously capitalized domestic R&E costs.

The Company has included impacts for the provisions in effect for tax years beginning after December 31, 2024 in its financial statements for the year ending December 31, 2025.

The OBBBA had no impact on the Company's current or deferred tax expense as the Company is in a tax loss position and maintains a valuation allowance.

Interest and penalty charges, if any, related to unrecognized tax benefits would be classified within income tax benefit (expense) in the accompanying consolidated statements of operations and comprehensive loss.

As of December 31, 2025, the Company had no accrued interest related to uncertain tax positions.

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There are currently no federal, state or foreign audits in progress.

Employee Benefit Plans

Defined Contribution Plan

Employee Benefit Plan

The Company maintains a defined contribution plan, or the 401(k) Plan, under Section 401(k) of the Internal Revenue Code.

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Contributions by the Company totaled $ 0.4 million and $ 0.2 million during the years ended December 31, 2025 and 2024, respectively.

Employee Stock Purchase Plan

In June 2016, the Company approved the 2016 Employee Stock Purchase Plan, or the ESPP, which initially authorized 5,769 shares of common stock for future issuance under the ESPP to participating employees.

As of December 31, 2024, 45,795 shares remain available for future issuance under the ESPP.

In connection with the Merger, the Board of Directors suspended offerings under the ESPP.

The Company recognized no stock-based compensation expense under the ESPP for the year ended December 31, 2024 and $ 0.1 million of stock-based compensation expense under the ESPP for the year ended December 31, 2023.

Commitments and Contingencies

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In April 2023, in light of current market conditions, the Board of Directors took steps to extend the Company’s cash runway by pausing further development of the Company’s product candidate, SEL-302, for the treatment of methylmalonic acidemia and conducting a targeted headcount reduction.

On August 17, 2023, the Company announced additional steps to extend cash runway and maximize value for stockholders by continuing to prioritize development of the Company’s product candidate, SEL-212, and support of its collaboration with Astellas for Xork, and pausing further development of all of the Company’s other clinical and preclinical product candidates that it was no longer actively advancing.

As a result of these measures, the Company implemented a restructuring plan that resulted in an approximate 90 % reduction of the Company’s existing headcount as of December 31, 2024.

On August 17, 2023, the Company announced additional steps to extend cash runway and maximize value for stockholders by continuing to prioritize development of the Company’s product candidate, NASP, and support of its collaboration with Astellas for Xork, and pausing further development of all of the Company’s other clinical and preclinical product candidates that it was no longer actively advancing.

As a result of these measures, the Company implemented a restructuring plan that resulted in an approximate 90 % reduction of the Company’s headcount as of April 2023.

The following table summarizes the change in the Company’s accrued restructuring balance included in accrued expenses and other current liabilities on its consolidated balance sheets (in thousands):

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The Company recorded these restructuring charges based on each employee’s role to the respective research and development and general and administrative operating expense categories on its consolidated statements of operations and comprehensive loss.

For the years ended December 31, 2024 and 2023, the Company recognized $ 0.2 million and $ 5.6 million in research and development expenses, respectively, and $ 0.6 million and $ 0.8 million in general and administrative expenses, respectively.

Payments for the restructuring plan were substantially complete by June 30, 2024.

For the year ended December 31, 2025, the Company recognized no restructuring charges .

For the year ended December 31, 2024, the Company recognized $ 0.2 million in research and development expenses and $ 0.6 million in general and administrative expenses .

Payments for the restructuring plan were completed in the first quarter of 2025.

Segment Reporting

Factors used in determining the reportable segment include the nature of the Company’s operating activities, the organizational and reporting structure and the type of information reviewed by the CODM to allocate resources and evaluate financial performance.

The accounting policies of the segment are the same as those described in Note 3.

The accounting policies of the segment are the same as those described in Note 2 “Summary of Significant Accounting Policies”.

The following table presents selected financial information with respect to the Company’s single operating segment for the years ended December 31, 2025 and 2024 (in thousands):

Year Ended December 31,

Collaboration and license revenue $ 38,275 $ 26,004

Grant revenue 638 —

Total revenue 38,913 26,004

Collaboration and license $ 400 $ 38,275

Grant 2,397 638

Total revenues 2,797 38,913

Operating expenses:

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General and administrative 31,468 30,126

Impairment of long-lived assets 7,579 710

Other expense, net (1) 33,527 133,294

Impairment of indefinite-lived intangible and long-lived assets

Other (income) expense, net (1)

( 13,103 ) 33,527

Net loss $ ( 130,302 ) $ ( 77,424 )

(1) Includes impairment of long-lived assets, interest income, foreign currency transaction, net, interest expense, change in fair value of warrant liabilities, change in fair value of contingent value right liability, change in fair value of forward contract liabilities, other income, net, and income tax (expense) benefit.

(1) Includes interest income;

gain on change in fair value of warrant liabilities;

loss on change in fair value of contingent value right liability;

loss on change in fair value of forward contract liabilities;

other (expense) income, net and income tax benefit (expense).

Subsequent Events

The Company has evaluated subsequent events through the date on which the consolidated financial statements were issued.

The Company has concluded that no subsequent events have occurred that require disclosure, except as disclosed within these consolidated financial statements.

The Company has concluded that no subsequent events have occurred that require disclosure.

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 9A. Controls and Procedures