<SEC-DOCUMENT>0001209191-21-010174.txt : 20210212
<SEC-HEADER>0001209191-21-010174.hdr.sgml : 20210212
<ACCEPTANCE-DATETIME>20210212164614
ACCESSION NUMBER:		0001209191-21-010174
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20201201
FILED AS OF DATE:		20210212
DATE AS OF CHANGE:		20210212

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Socks David A
		CENTRAL INDEX KEY:			0001378847

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39094
		FILM NUMBER:		21628699

	MAIL ADDRESS:	
		STREET 1:		C/O CADENCE PHARMACEUTICALS, INC.
		STREET 2:		12481 HIGH BLUFF DRIVE, SUITE 200
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92130

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>5
<SEQUENCE>1
<FILENAME>doc5.xml
<DESCRIPTION>FORM 5 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2020-12-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378847</rptOwnerCik>
            <rptOwnerName>Socks David A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PHATHOM PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>100 CAMPUS DRIVE, SUITE 102</rptOwnerStreet2>
            <rptOwnerCity>FLORHAM PAK</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07932</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-12-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>27000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1505945</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>David A. Socks 2013 Revocable Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Larry Miller, Attorney-in-Fact for David A. Socks</signatureName>
        <signatureDate>2021-02-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
