Cartesian Therapeutics, Inc. — Declaration of Voting Results & Voting Rights Announcements 2026

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of

the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 12, 2026

CARTESIAN THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

7495 New Horizon Way, Frederick, MD 21703

(Address of principal executive offices)(Zip Code)

( 301 ) 348-8698

Registrant’s telephone number, including area code

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Item 5.07 Submission of Matters to a Vote of Security Holders.

On June 12, 2026, Cartesian Therapeutics, Inc. (the “Company”) held the 2026 Annual Meeting of Stockholders (the “Annual Meeting”). A total of 24,151,536 shares of the Company’s common stock, par value $0.0001 per share (the “common stock”), were present electronically or represented by proxy at the meeting, representing approximately 82.42% of the Company’s outstanding common stock as of the April 14, 2026 record date. The following are the voting results for the proposals considered and voted upon at the meeting, all of which were described in the Proxy Statement.

Proposal 1 - Election of three Class I Directors to serve until the 2029 Annual Meeting of Stockholders, and until their respective successors have been duly elected and qualified.

Based on the votes set forth above, each director nominee was duly elected to serve until the Company’s 2029 Annual Meeting of Stockholders, and until their respective successors have been duly elected and qualified.

Proposal 2 - Approval, on a non-binding and advisory basis, of a resolution approving the compensation of the Company’s named executive officers.

Based on the votes set forth above, the stockholders approved, on a non-binding and advisory basis, a resolution approving the compensation of our named executive officers.

Proposal 3 - Ratification of the appointment of Ernst & Young LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2026.

Based on the votes set forth above, the stockholders ratified the appointment of Ernst & Young LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2026.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.