Emily English - 30 Dec 2025 Form 4 Insider Report for Cartesian Therapeutics, Inc. (RNAC)

Role: Chief Operations Officer
Signature: /s/ Matthew Bartholomae, Attorney-in-Fact for Emily English
Issuer symbol: RNAC
Transactions as of: 30 Dec 2025
Net transactions value: +$24,750
Form type: 4
Filing time: 02 Jan 2026, 16:03:30 UTC
Previous filing: 02 Dec 2025
Next filing: 06 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
English Emily	Chief Operations Officer	C/O CARTESIAN THERAPEUTICS, INC., 7495 NEW HORIZON WAY, FREDERICK	/s/ Matthew Bartholomae, Attorney-in-Fact for Emily English	02 Jan 2026	0002019791

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	RNAC	Common Stock	Options Exercise	$24,750	+7,500	+12%	$3.30	70,226	30 Dec 2025	Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	RNAC	Stock Option (Right to Buy)	Options Exercise		-7,500	-28%		19,369	30 Dec 2025	Common Stock	7,500	$3.30	Direct	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	These options are currently fully vested and exercisable.
F2	On November 13, 2023, the issuer acquired the Delaware corporation which was then-known as Cartesian Therapeutics, Inc. ("Old Cartesian") in accordance with the terms of an Agreement and Plan of Merger, dated November 13, 2023. Options to purchase Old Cartesian common stock held by the reporting person were converted into options to purchase shares of the issuer's common stock in connection with the merger.

Content

These options are currently fully vested and exercisable.

On November 13, 2023, the issuer acquired the Delaware corporation which was then-known as Cartesian Therapeutics, Inc. ("Old Cartesian") in accordance with the terms of an Agreement and Plan of Merger, dated November 13, 2023. Options to purchase Old Cartesian common stock held by the reporting person were converted into options to purchase shares of the issuer's common stock in connection with the merger.