<SEC-DOCUMENT>0001395064-21-000153.txt : 20210709
<SEC-HEADER>0001395064-21-000153.hdr.sgml : 20210709
<ACCEPTANCE-DATETIME>20210709060942
ACCESSION NUMBER:		0001395064-21-000153
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210707
FILED AS OF DATE:		20210709
DATE AS OF CHANGE:		20210709

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TAKEDA PHARMACEUTICAL CO LTD
		CENTRAL INDEX KEY:			0001395064
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39094
		FILM NUMBER:		211081610

	BUSINESS ADDRESS:	
		STREET 1:		1-1, NIHONBASHI-HONCHO 2-CHOME, CHUO-KU
		CITY:			TOKYO
		STATE:			M0
		ZIP:			103-8668
		BUSINESS PHONE:		81332782111

	MAIL ADDRESS:	
		STREET 1:		1-1, NIHONBASHI-HONCHO 2-CHOME, CHUO-KU
		CITY:			TOKYO
		STATE:			M0
		ZIP:			103-8668

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Phathom Pharmaceuticals, Inc.
		CENTRAL INDEX KEY:			0001783183
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				824151574
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		100 CAMPUS DRIVE,
		STREET 2:		SUITE 102
		CITY:			FLORHAM PARK
		STATE:			NJ
		ZIP:			07932
		BUSINESS PHONE:		(877) 742-8466

	MAIL ADDRESS:	
		STREET 1:		100 CAMPUS DRIVE,
		STREET 2:		SUITE 102
		CITY:			FLORHAM PARK
		STATE:			NJ
		ZIP:			07932
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_162582536885803.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-07-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001783183</issuerCik>
        <issuerName>Phathom Pharmaceuticals, Inc.</issuerName>
        <issuerTradingSymbol>PHAT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001395064</rptOwnerCik>
            <rptOwnerName>TAKEDA PHARMACEUTICAL CO LTD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1-1, NIHONBASHI-HONCHO 2-CHOME</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHUO-KU, TOKYO</rptOwnerCity>
            <rptOwnerState>M0</rptOwnerState>
            <rptOwnerZipCode>103-8668</rptOwnerZipCode>
            <rptOwnerStateDescription>JAPAN</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>2021-07-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2609</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>35.05</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>871305</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The sales reported herein were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on April 2, 2021.</footnote>
        <footnote id="F2">Reflects the weighted average sale price.  This transaction was executed in multiple trades at prices ranging from $35.00 to $35.26.  Information regarding the number of shares sold at each separate price will be provided upon request by the Staff of the Securities and Exchange Commission, the Issuer or any security holder of the Issuer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Amit Singh, Senior Vice President and Head of Treasury of Takeda Pharmaceutical Company
Limited</signatureName>
        <signatureDate>2021-07-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
