<SEC-DOCUMENT>0001596771-18-000053.txt : 20180503
<SEC-HEADER>0001596771-18-000053.hdr.sgml : 20180503
<ACCEPTANCE-DATETIME>20180503163251
ACCESSION NUMBER:		0001596771-18-000053
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180501
FILED AS OF DATE:		20180503
DATE AS OF CHANGE:		20180503

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Gullans Steven R. Ph.D.
		CENTRAL INDEX KEY:			0001571997

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37809
		FILM NUMBER:		18804330

	MAIL ADDRESS:	
		STREET 1:		C/O EXCEL VENTURE MANAGEMENT, LLC
		STREET 2:		800 BOYLSTON ST., STE 2825
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02199

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Gemphire Therapeutics Inc.
		CENTRAL INDEX KEY:			0001638287
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				472389984
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		17199 N. LAUREL PARK DRIVE
		STREET 2:		SUITE 401
		CITY:			LIVONIA
		STATE:			MI
		ZIP:			48152
		BUSINESS PHONE:		248-980-6538

	MAIL ADDRESS:	
		STREET 1:		17199 N. LAUREL PARK DRIVE
		STREET 2:		SUITE 401
		CITY:			LIVONIA
		STATE:			MI
		ZIP:			48152
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-05-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001638287</issuerCik>
        <issuerName>Gemphire Therapeutics Inc.</issuerName>
        <issuerTradingSymbol>GEMP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001571997</rptOwnerCik>
            <rptOwnerName>Gullans Steven R. Ph.D.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>17199 N. LAUREL PARK DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 401</rptOwnerStreet2>
            <rptOwnerCity>LIVONIA</rptOwnerCity>
            <rptOwnerState>MI</rptOwnerState>
            <rptOwnerZipCode>48152</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>5.56</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-05-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>150000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2028-04-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>150000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>150000</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The option vests in a series of 48 successive equal monthly installments on the last day of each month, commencing on the grant date.  The option includes an early exercise provision, subject to the issuer's right of repurchase with respect to any unvested shares of common stock.</footnote>
        <footnote id="F2">The reporting person ceased to be a manager of Excel Venture Fund II, L.P. on May 1, 2018 and will no longer report beneficial ownership of the issuer's securities owned by such entity.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Stephanie Swan, by Power of Attorney</signatureName>
        <signatureDate>2018-05-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
