<SEC-DOCUMENT>0001453687-24-000112.txt : 20240927
<SEC-HEADER>0001453687-24-000112.hdr.sgml : 20240927
<ACCEPTANCE-DATETIME>20240927161336
ACCESSION NUMBER:		0001453687-24-000112
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240925
FILED AS OF DATE:		20240927
DATE AS OF CHANGE:		20240927

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SPRINGER TIMOTHY A
		CENTRAL INDEX KEY:			0001055624
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37798
		FILM NUMBER:		241335024

	MAIL ADDRESS:	
		STREET 1:		36 WOODMAN ROAD
		CITY:			CHESTNUT HILL
		STATE:			MA
		ZIP:			02467

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Cartesian Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001453687
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		704 QUINCE ORCHARD RD
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878
		BUSINESS PHONE:		617-923-1400

	MAIL ADDRESS:	
		STREET 1:		704 QUINCE ORCHARD RD
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SELECTA BIOSCIENCES INC
		DATE OF NAME CHANGE:	20090109
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1727468009.xml
<DESCRIPTION>FORM 4
<TEXT>
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<ownershipDocument>

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    <periodOfReport>2024-09-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001453687</issuerCik>
        <issuerName>Cartesian Therapeutics, Inc.</issuerName>
        <issuerTradingSymbol>RNAC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001055624</rptOwnerCik>
            <rptOwnerName>SPRINGER TIMOTHY A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>36 WOODMAN ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHESTNUT HILL</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02467</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
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    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
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                <value>Series B Non-Voting Convertible Preferred Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-09-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
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            <transactionAmounts>
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                <transactionPricePerShare>
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                <directOrIndirectOwnership>
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        <nonDerivativeTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
                <value>2024-09-25</value>
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                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Series B Non-Voting Convertible Preferred Stock</value>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <transactionShares>
                    <value>1307</value>
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                <transactionPricePerShare>
                    <footnoteId id="F1"/>
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                <transactionAcquiredDisposedCode>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By wife</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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                <value>2024-09-25</value>
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                    <value>12816</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By wife</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On September 20, 2024, the issuer held a special meeting of stockholders (the &quot;Special Meeting&quot;). At the Special Meeting, the stockholders of the issuer approved the conversion of the issuer's Series B Non-Voting Convertible Preferred Stock (&quot;Series B Preferred Stock&quot;) into shares of common stock. On September 25, 2024, the conversion of the majority of the shares of Series B Preferred Stock occurred automatically (the &quot;Automatic Conversion&quot;). The remaining shares of Series B Preferred Stock remain subject to certain beneficial ownership limitations described in the issuer's filings with the Securities and Exchange Commission. At the time of the Automatic Conversion, all of the shares of Series B Preferred Stock beneficially owned by the reporting person converted into shares of common stock.</footnote>
        <footnote id="F2">Held by TAS Partners LLC. The reporting person is the managing member of TAS Partners LLC. The reporting person disclaims beneficial ownership of the securities held by TAS Partners LLC except to the extent of his pecuniary interest therein, if any.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Matthew Bartholomae, Attorney-in-Fact for Timothy A. Springer</signatureName>
        <signatureDate>2024-09-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
