Company: RNAC
Filing Date: 2025-01-08
Form Type: 424B3
Source: 0001140361-25-000626
Chunk: 25

Company: Cartesian Therapeutics, Inc.
Filing Date: 2025-01-08
Form: 424B3
Chunk 25
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 Act. As sales agent, Leerink Partners will not engage in any transactions that stabilize our Common Stock.

The Common Stock is listed on Nasdaq under the symbol “RNAC.”

Leerink Partners and/or its affiliates have provided, and may in the future provide, various investment banking, commercial banking, financial advisory and other financial services for us and our affiliates, for which services they have received, and may in the future receive, customary fees.

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### LEGAL MATTERS
Covington & Burling LLP, New York, New York, will pass upon certain legal matters relating to the issuance and sale of the securities offered hereby on behalf of Cartesian Therapeutics, Inc. Leerink Partners LLC is being represented in connection with this offering by Cooley LLP, New York, New York.

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### EXPERTS
The consolidated financial statements of Cartesian Therapeutics, Inc. at December 31, 2023 and 2022, and for each of the three years in the period ended December 31, 2023, incorporated by reference in this Prospectus and Registration Statement have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their report thereon appearing elsewhere herein, and are incorporated by reference in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

The financial statements of Cartesian Therapeutics, Inc. as of and for the years ended December 31, 2022 and 2021 appearing in the Current Report on Form 8-K/A filed on January 23, 2024 of Cartesian Therapeutics, Inc. (formerly known as Selecta Biosciences, Inc.) incorporated by reference in this Prospectus and in the Registration Statement have been so incorporated in reliance on the report of BDO USA, P.C., independent auditors, given on the authority of said firm as experts in auditing and accounting.

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#### Up to $100,000,000

#### Common Stock

### PROSPECTUS

#### Leerink Partners

#### January 8, 2025