<SEC-DOCUMENT>0001209191-21-038932.txt : 20210608
<SEC-HEADER>0001209191-21-038932.hdr.sgml : 20210608
<ACCEPTANCE-DATETIME>20210608163813
ACCESSION NUMBER:		0001209191-21-038932
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210604
FILED AS OF DATE:		20210608
DATE AS OF CHANGE:		20210608

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			O'Donnell Niall
		CENTRAL INDEX KEY:			0001780235

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38981
		FILM NUMBER:		211002578

	MAIL ADDRESS:	
		STREET 1:		C/O RIVERVEST VENTURE PARTNERS
		STREET 2:		101 SOUTH HANLEY RD., STE 1850
		CITY:			ST. LOUIS
		STATE:			MO
		ZIP:			63105

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Mirum Pharmaceuticals, Inc.
		CENTRAL INDEX KEY:			0001759425
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				831281555
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		950 TOWER LANE, SUITE 1050
		CITY:			FOSTER CITY
		STATE:			CA
		ZIP:			94404
		BUSINESS PHONE:		650-667-4085

	MAIL ADDRESS:	
		STREET 1:		950 TOWER LANE, SUITE 1050
		CITY:			FOSTER CITY
		STATE:			CA
		ZIP:			94404
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-06-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001759425</issuerCik>
        <issuerName>Mirum Pharmaceuticals, Inc.</issuerName>
        <issuerTradingSymbol>MIRM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001780235</rptOwnerCik>
            <rptOwnerName>O'Donnell Niall</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RIVERVEST VENTURE PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>101 SOUTH HANLEY ROAD, STE. 1850</rptOwnerStreet2>
            <rptOwnerCity>ST. LOUIS</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>63105</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>16.88</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-06-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>17000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-06-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>17000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares vest on the first anniversary of the grant date, provided that the option will in any case be fully vested on the date of the Company's 2022 annual stockholder meeting.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Jody Howe, Attorney-in-Fact</signatureName>
        <signatureDate>2021-06-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
