<SEC-DOCUMENT>0001104659-20-080639.txt : 20200702
<SEC-HEADER>0001104659-20-080639.hdr.sgml : 20200702
<ACCEPTANCE-DATETIME>20200702164648
ACCESSION NUMBER:		0001104659-20-080639
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200630
FILED AS OF DATE:		20200702
DATE AS OF CHANGE:		20200702

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RA CAPITAL MANAGEMENT, L.P.
		CENTRAL INDEX KEY:			0001346824
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38223
		FILM NUMBER:		201010237

	BUSINESS ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-778-2500

	MAIL ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER NAME:	
		FORMER CONFORMED NAME:	RA CAPITAL MANAGEMENT, LLC
		DATE OF NAME CHANGE:	20051213

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RA Capital Healthcare Fund LP
		CENTRAL INDEX KEY:			0001315082
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38223
		FILM NUMBER:		201010238

	BUSINESS ADDRESS:	
		STREET 1:		200 BERKELEY STREET
		STREET 2:		18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6177782500

	MAIL ADDRESS:	
		STREET 1:		200 BERKELEY STREET
		STREET 2:		18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER NAME:	
		FORMER CONFORMED NAME:	RA Capital Biotech Fund LP
		DATE OF NAME CHANGE:	20050121

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kolchinsky Peter
		CENTRAL INDEX KEY:			0001384859

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38223
		FILM NUMBER:		201010239

	MAIL ADDRESS:	
		STREET 1:		200 BERKELEY STREET
		STREET 2:		18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Shah Rajeev M.
		CENTRAL INDEX KEY:			0001619841

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38223
		FILM NUMBER:		201010240

	MAIL ADDRESS:	
		STREET 1:		200 BERKELEY STREET
		STREET 2:		18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RHYTHM PHARMACEUTICALS, INC.
		CENTRAL INDEX KEY:			0001649904
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				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>
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<TYPE>4
<SEQUENCE>1
<FILENAME>tm2024054-2_4.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
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<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-06-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001346824</rptOwnerCik>
            <rptOwnerName>RA CAPITAL MANAGEMENT, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <otherText></otherText>
        </reportingOwnerRelationship>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001315082</rptOwnerCik>
            <rptOwnerName>RA Capital Healthcare Fund LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RA CAPITAL MANAGEMENT, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>200 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
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            <otherText></otherText>
        </reportingOwnerRelationship>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001384859</rptOwnerCik>
            <rptOwnerName>Kolchinsky Peter</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RA CAPITAL MANAGEMENT, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>200 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
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            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001619841</rptOwnerCik>
            <rptOwnerName>Shah Rajeev M.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RA CAPITAL MANAGEMENT, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>200 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-06-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>61901</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.1521</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5210088</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-07-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>25527</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>21.8714</value>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5184561</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-07-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>44153</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.0363</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5140408</value>
                    <footnoteId id="F7"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This transaction was executed in multiple trades at prices ranging from $21.90 to $22.41; the price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide full information regarding the number of shares and prices at which these transactions were effected upon request to the SEC staff, the issuer, or a security holder of the issuer.</footnote>
        <footnote id="F2">RA Capital Management, L.P. (the &quot;Adviser&quot;) is the investment manager for the RA Capital Healthcare Fund, L.P. (the &quot;Fund&quot;) and a separately managed account (the &quot;Account&quot;). The general partner of the Adviser is RA Capital Management GP, LLC (the &quot;Adviser GP&quot;), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky, and Mr. Shah may be deemed indirect beneficial owners of the reported securities for purposes of Section 13(d) of the Securities Exchange Act of 1934 (the &quot;Act&quot;).</footnote>
        <footnote id="F3">They disclaim beneficial ownership of any of the reported securities for the purpose of determining whether they are subject to Section 16 of the Act, however, in reliance on Rule 16a-1(a)(1)(v) and (vii).  To the extent that they might be deemed subject to Section 16, they disclaim beneficial ownership of securities held by the Fund for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein, and disclaim any pecuniary interest in securities held in the Account for purposes of Rule 16a-1(a)(2).</footnote>
        <footnote id="F4">The filing of this Form 4 shall not be construed as an admission that either the Adviser, the Adviser GP, Dr. Kolchinsky, or Mr. Shah is or was for the purposes of Section 16(a), or otherwise, the beneficial owner of any of the securities held in the Account.</footnote>
        <footnote id="F5">This transaction was executed in multiple trades at prices ranging from $21.75 to $22.09; the price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide full information regarding the number of shares and prices at which these transactions were effected upon request to the SEC staff, the issuer, or a security holder of the issuer.</footnote>
        <footnote id="F6">This transaction was executed in multiple trades at prices ranging from $22.00 to $22.165; the price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide full information regarding the number of shares and prices at which these transactions were effected upon request to the SEC staff, the issuer, or a security holder of the issuer.</footnote>
        <footnote id="F7">Includes 4,599,403 shares held by the Fund and 541,005 shares held by the Account.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.</signatureName>
        <signatureDate>2020-07-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Peter Kolchinsky, Manager of RA Capital Healthcare GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P.</signatureName>
        <signatureDate>2020-07-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Peter Kolchinsky, individually</signatureName>
        <signatureDate>2020-07-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Rajeev Shah, individually</signatureName>
        <signatureDate>2020-07-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</SEC-DOCUMENT>
