<SEC-DOCUMENT>0001104659-25-063080.txt : 20250626
<SEC-HEADER>0001104659-25-063080.hdr.sgml : 20250626
<ACCEPTANCE-DATETIME>20250626165604
ACCESSION NUMBER:		0001104659-25-063080
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250624
FILED AS OF DATE:		20250626
DATE AS OF CHANGE:		20250626

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bedrosian Camille L
		CENTRAL INDEX KEY:			0001326969
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38223
		FILM NUMBER:		251081097

	MAIL ADDRESS:	
		STREET 1:		C/O ULTRAGENYX PHARMACEUTICAL INC.
		STREET 2:		60 LEVERONI COURT
		CITY:			NOVATO
		STATE:			CA
		ZIP:			94949

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RHYTHM PHARMACEUTICALS, INC.
		CENTRAL INDEX KEY:			0001649904
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				462159271
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		222 BERKELEY STREET
		STREET 2:		12TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		857-264-4280

	MAIL ADDRESS:	
		STREET 1:		222 BERKELEY STREET
		STREET 2:		12TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RHYTHM METABOLIC, INC.
		DATE OF NAME CHANGE:	20150803
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm2519230-3_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-06-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001649904</issuerCik>
        <issuerName>RHYTHM PHARMACEUTICALS, INC.</issuerName>
        <issuerTradingSymbol>RYTM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001326969</rptOwnerCik>
            <rptOwnerName>Bedrosian Camille L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RHYTHM PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>222 BERKELEY STREET, 12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>63.66</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-06-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7037</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2035-06-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7037</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7037</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-06-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4712</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4712</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4712</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The options fully vest upon the earlier of (i) June 24, 2026 or (ii) the day immediately prior to the date of the Issuer's next annual meeting of the stockholders to be held in 2026, subject to the Reporting Person's continued service on such vesting date.</footnote>
        <footnote id="F2">Each restricted stock unit represents a contingent right to receive one share of Issuer common stock.</footnote>
        <footnote id="F3">The restricted stock units fully vest upon the earlier of (i) June 24, 2026 or (ii) the day immediately prior to the date of the Issuer's next annual meeting of the stockholders to be held in 2026, subject to the Reporting Person's continued service on such vesting date. The restricted stock units have no expiration date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Stephen Vander Stoep, attorney-in-fact for Camille L. Bedrosian</signatureName>
        <signatureDate>2025-06-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
