of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth in

Chief Medical Officer — Milos Miljkovic, M.D.: Dr. Miljkovic resigned from his position as Chief Medical Officer.

The issuance of any Conversion Shares underlying the outstanding principal amount of the Term Loans will be made in reliance upon the exemption from registration contained in Section 4(a)(2) of the Securities Act of 1933, as amended, and/or Rule 506 of Regulation D thereunder.

Entry into a Material Definitive Agreement. Loan and Security Agreement On May 22, 2026, Cartesian Therapeutics, Inc. (the “Company”) and its wholly-owned subsidiary, Cartesian Bio, LLC, as borrowers (“Borrowers”), entered into a Loan and Security Agreement (the “Loan Agreement”) with certain financial institutions party thereto as lenders (the “Lenders”), K2 HealthVentures LLC, as administrative agent (in such capacity, the “Administrative Agent”) and Ankura Trust Company, LLC, as collateral…

of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Director — Murat Kalayoglu, M.D., Ph.D.: Dr. Kalayoglu resigned from the Board to pursue other opportunities.

of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Class II director — Adrian Bot, M.D., Ph.D.: Dr. Adrian Bot was appointed as a Class II director of Cartesian Therapeutics, Inc.

Other Events On November 13, 2025, the Company announced initial data from its ongoing Phase 2 trial of Descartes-08 in participants with SLE. The Phase 2 open-label trial was designed to evaluate outpatient administration of Descartes-08 without preconditioning chemotherapy or integrating vectors for the treatment of participants with moderate or severe SLE refractory to immunosuppressant therapy. The primary outcome measure assesses safety and tolerability, with secondary outcome measures a…

of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Chairman of the Board — Carrie S. Cox: Resigned due to new commitments at another company.

Chief Scientific Officer — Christopher Jewell, Ph.D.: The position of Chief Scientific Officer was eliminated and Dr. Christopher Jewell's employment was terminated without cause.

Chief Accounting Officer — June Seymour: The Company appointed June Seymour as Chief Accounting Officer, bringing significant financial leadership experience to the role.

of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Chief Technology Officer — Metin Kurtoglu: Dr. Metin Kurtoglu is departing from his role as Chief Technology Officer with a consulting agreement and separation package.

Other Information. On April 8, 2025, the Company announced 12-month efficacy and safety data from the Phase 2b trial of Descartes-08 in participants with generalized MG. Participants dosed with a single six-week course of treatment of Descartes-08 were observed to continue to experience a sustained benefit in symptoms of MG at the 12-month assessment. The primary efficacy dataset for the follow-up portion of the trial consisted of a modified intent-to-treat (“mITT”) population of all subjects…

of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Other Information. On December 3, 2024, the Company announced positive updated efficacy and safety data from its Phase 2b trial of Descartes-08 in participants with MG. In the Phase 2b double-blind, placebo-controlled, crossover trial, a total of 36 heavily pre-treated, highly symptomatic participants with MG were randomized 1:1 to receive either Descartes-08 or placebo administered as six weekly outpatient infusions without preconditioning chemotherapy. The primary efficacy dataset for the f…

of this Form 8-K, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

Results of Operations and Financial Condition. On August 8, 2024, Cartesian Therapeutics, Inc. (the “Company”) announced its financial results for the quarter ended June 30, 2024. The full text of the press release issued in connection with the announcement is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Entry into a Material Definitive Agreement. On July 2, 2024, Cartesian Therapeutics, Inc., a Delaware corporation (the “Company”), entered into a Securities Purchase Agreement (the “Purchase Agreement”) for a private placement (the “Private Placement”) with certain institutional and accredited investors (each, a “Purchaser” and collectively, the “Purchasers”). The closing of the Private Placement is expected to occur on July 3, 2024 (the “Closing Date”). Pursuant to the Purchase Agreement, th…

Class II director — Kemal Malik, MBBS: Dr. Kemal Malik was appointed as a Class II director of the company.

Regulation FD Disclosure. On July 2, 2024, the Company issued a press release announcing the Private Placement. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K. On July 2, 2024, the Company issued a press release announcing positive topline data from its Phase 2b trial of Descartes-08 in patients with myasthenia gravis. A copy of the press release is furnished as Exhibit 99.2 to this Current Report on Form 8-K. The Company will host a conference cal…