<SEC-DOCUMENT>0000899243-20-019123.txt : 20200714
<SEC-HEADER>0000899243-20-019123.hdr.sgml : 20200714
<ACCEPTANCE-DATETIME>20200714201120
ACCESSION NUMBER:		0000899243-20-019123
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200710
FILED AS OF DATE:		20200714
DATE AS OF CHANGE:		20200714

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Longitude Capital Partners III, LLC
		CENTRAL INDEX KEY:			0001713663
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39122
		FILM NUMBER:		201028100

	BUSINESS ADDRESS:	
		STREET 1:		800 EL CAMINO, SUITE 220
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025
		BUSINESS PHONE:		650-845-5700

	MAIL ADDRESS:	
		STREET 1:		800 EL CAMINO, SUITE 220
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Longitude Venture Partners III, L.P.
		CENTRAL INDEX KEY:			0001674099
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39122
		FILM NUMBER:		201028101

	BUSINESS ADDRESS:	
		STREET 1:		800 EL CAMINO REAL, SUITE 220
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025
		BUSINESS PHONE:		650-845-5700

	MAIL ADDRESS:	
		STREET 1:		800 EL CAMINO REAL, SUITE 220
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Tammenoms Bakker Juliet
		CENTRAL INDEX KEY:			0001431159

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39122
		FILM NUMBER:		201028102

	MAIL ADDRESS:	
		STREET 1:		LONGITUDE CAPITAL MANAGEMENT CO., LLC
		STREET 2:		800 EL CAMINO REAL, SUITE 220
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ENRIGHT PATRICK G
		CENTRAL INDEX KEY:			0001253886

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39122
		FILM NUMBER:		201028103

	MAIL ADDRESS:	
		STREET 1:		CO LONGITUDE CAPITAL PARTNERS LLC
		STREET 2:		800 EL CAMINO REAL, SUITE 220
		CITY:			MENLO PARK
		STATE:			CA
		ZIP:			94025

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			89bio, Inc.
		CENTRAL INDEX KEY:			0001785173
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				831114349
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		535 MISSION STREET
		STREET 2:		14TH FLOOR
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94105
		BUSINESS PHONE:		4155004614

	MAIL ADDRESS:	
		STREET 1:		535 MISSION STREET
		STREET 2:		14TH FLOOR
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94105
</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>2020-07-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001785173</issuerCik>
        <issuerName>89bio, Inc.</issuerName>
        <issuerTradingSymbol>ETNB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001713663</rptOwnerCik>
            <rptOwnerName>Longitude Capital Partners III, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2740 SAND HILL RD 2ND FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001674099</rptOwnerCik>
            <rptOwnerName>Longitude Venture Partners III, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2740 SAND HILL RD 2ND FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001431159</rptOwnerCik>
            <rptOwnerName>Tammenoms Bakker Juliet</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2740 SAND HILL RD 2ND FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001253886</rptOwnerCik>
            <rptOwnerName>ENRIGHT PATRICK G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2740 SAND HILL RD 2ND FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-07-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>109090</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>27.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2600877</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On July 10, 2020, Longitude Venture Partners III, L.P. (&quot;Longitude Venture III&quot;) purchased 109,090 shares of the Issuer's common stock at a price of $27.50 per share in the Issuer's follow-on public offering.</footnote>
        <footnote id="F2">These shares are held directly by Longitude Venture III. Longitude Capital Partners III, LLC (&quot;Longitude Capital III&quot;) is the general partner of Longitude Venture III and may be deemed to have voting, investment and dispositive power with respect to these securities. Patrick G. Enright and Juliet Tammenoms Bakker are the managing members of Longitude Capital III (each a &quot;Manager&quot; and collectively, the &quot;Managers&quot;) and may each be deemed to share voting, investment and dispositive power with respect to these securities. Each of Longitude Capital III and the Managers disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Longitude Venture Partners III, L.P.; By /s/ Patrick G. Enright, Managing Member</signatureName>
        <signatureDate>2020-07-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Longitude Capital Partners III, LLC; By /s/ Patrick G. Enright, Managing Member</signatureName>
        <signatureDate>2020-07-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Juliet Tammenoms Bakker</signatureName>
        <signatureDate>2020-07-14</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Patrick G. Enright</signatureName>
        <signatureDate>2020-07-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
