<SEC-DOCUMENT>0001415889-25-004199.txt : 20250214
<SEC-HEADER>0001415889-25-004199.hdr.sgml : 20250214
<ACCEPTANCE-DATETIME>20250214173841
ACCESSION NUMBER:		0001415889-25-004199
CONFORMED SUBMISSION TYPE:	SCHEDULE 13G
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20250214
DATE AS OF CHANGE:		20250214

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Upstream Bio, Inc.
		CENTRAL INDEX KEY:			0002022626
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-94651
		FILM NUMBER:		25631329

	BUSINESS ADDRESS:	
		STREET 1:		890 WINTER STREET, SUITE 200
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		781-208-2466

	MAIL ADDRESS:	
		STREET 1:		890 WINTER STREET, SUITE 200
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Decheng Capital Global Life Sciences Fund IV, L.P.
		CENTRAL INDEX KEY:			0001834150
		ORGANIZATION NAME:           	
		IRS NUMBER:				981568621
		STATE OF INCORPORATION:			E9
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G

	BUSINESS ADDRESS:	
		STREET 1:		C/O MAPLES CORPORATE SERVICES LIMITED
		STREET 2:		UGLAND HOUSE, P.O. BOX 309
		CITY:			GRAND CAYMAN
		STATE:			E9
		ZIP:			KY1-1104
		BUSINESS PHONE:		345-949-8066

	MAIL ADDRESS:	
		STREET 1:		C/O MAPLES CORPORATE SERVICES LIMITED
		STREET 2:		UGLAND HOUSE, P.O. BOX 309
		CITY:			GRAND CAYMAN
		STATE:			E9
		ZIP:			KY1-1104
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13G
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/schedule13g" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>SCHEDULE 13G</submissionType>
	    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001834150</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>





    </filerInfo>
  </headerData>

  <formData>
    <coverPageHeader>
	      <securitiesClassTitle>Common Stock, par value $0.001 per share</securitiesClassTitle>
      <eventDateRequiresFilingThisStatement>12/31/2024</eventDateRequiresFilingThisStatement>
      <issuerInfo>
        <issuerCik>0002022626</issuerCik>        <issuerName>Upstream Bio, Inc. </issuerName>        <issuerCusip>91678A107</issuerCusip>
        <issuerPrincipalExecutiveOfficeAddress>
          <com:street1>890 Winter Street, Suite 200</com:street1>
                    <com:city>Waltham</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>02451</com:zipCode>
        </issuerPrincipalExecutiveOfficeAddress>
      </issuerInfo>

	        <designateRulesPursuantThisScheduleFiled>
	           <designateRulePursuantThisScheduleFiled>Rule 13d-1(d)</designateRulePursuantThisScheduleFiled>
						      </designateRulesPursuantThisScheduleFiled>

    </coverPageHeader>

	    <coverPageHeaderReportingPersonDetails>




    <reportingPersonName>Decheng Capital Global Life Sciences Fund IV, L.P.</reportingPersonName>

	  		<memberGroup>b</memberGroup>


		 <citizenshipOrOrganization>E9</citizenshipOrOrganization>

      <reportingPersonBeneficiallyOwnedNumberOfShares>
                <soleVotingPower>0.00</soleVotingPower>
                          <sharedVotingPower>3085293.00</sharedVotingPower>
                          <soleDispositivePower>0.00</soleDispositivePower>
                         <sharedDispositivePower>3085293.00</sharedDispositivePower>
             </reportingPersonBeneficiallyOwnedNumberOfShares>

              <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>3085293.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>


     	    <classPercent>5.8</classPercent>





	        <typeOfReportingPerson>PN</typeOfReportingPerson>









    </coverPageHeaderReportingPersonDetails>
	    <coverPageHeaderReportingPersonDetails>




    <reportingPersonName>Decheng Capital Management IV (Cayman), LLC</reportingPersonName>

	  		<memberGroup>b</memberGroup>


		 <citizenshipOrOrganization>E9</citizenshipOrOrganization>

      <reportingPersonBeneficiallyOwnedNumberOfShares>
                <soleVotingPower>0.00</soleVotingPower>
                          <sharedVotingPower>3085293.00</sharedVotingPower>
                          <soleDispositivePower>0.00</soleDispositivePower>
                         <sharedDispositivePower>3085293.00</sharedDispositivePower>
             </reportingPersonBeneficiallyOwnedNumberOfShares>

              <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>3085293.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>


     	    <classPercent>5.8</classPercent>











	        <typeOfReportingPerson>OO</typeOfReportingPerson>



    </coverPageHeaderReportingPersonDetails>
	    <coverPageHeaderReportingPersonDetails>




    <reportingPersonName>Decheng Capital Global Healthcare Fund (Master), LP </reportingPersonName>

	  		<memberGroup>b</memberGroup>


		 <citizenshipOrOrganization>E9</citizenshipOrOrganization>

      <reportingPersonBeneficiallyOwnedNumberOfShares>
                <soleVotingPower>0.00</soleVotingPower>
                          <sharedVotingPower>200000.00</sharedVotingPower>
                          <soleDispositivePower>0.00</soleDispositivePower>
                         <sharedDispositivePower>200000.00</sharedDispositivePower>
             </reportingPersonBeneficiallyOwnedNumberOfShares>

              <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>200000.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>


     	    <classPercent>0.4</classPercent>





	        <typeOfReportingPerson>PN</typeOfReportingPerson>









    </coverPageHeaderReportingPersonDetails>
	    <coverPageHeaderReportingPersonDetails>




    <reportingPersonName>Decheng Capital Global Healthcare GP, LLC </reportingPersonName>

	  		<memberGroup>b</memberGroup>


		 <citizenshipOrOrganization>E9</citizenshipOrOrganization>

      <reportingPersonBeneficiallyOwnedNumberOfShares>
                <soleVotingPower>0.00</soleVotingPower>
                          <sharedVotingPower>200000.00</sharedVotingPower>
                          <soleDispositivePower>0.00</soleDispositivePower>
                         <sharedDispositivePower>200000.00</sharedDispositivePower>
             </reportingPersonBeneficiallyOwnedNumberOfShares>

              <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>200000.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>


     	    <classPercent>0.4</classPercent>











	        <typeOfReportingPerson>OO</typeOfReportingPerson>



    </coverPageHeaderReportingPersonDetails>
	    <coverPageHeaderReportingPersonDetails>




    <reportingPersonName>Xiangmin Cui</reportingPersonName>

	  		<memberGroup>b</memberGroup>


		 <citizenshipOrOrganization>X1</citizenshipOrOrganization>

      <reportingPersonBeneficiallyOwnedNumberOfShares>
                <soleVotingPower>0.00</soleVotingPower>
                          <sharedVotingPower>3285293.00</sharedVotingPower>
                          <soleDispositivePower>0.00</soleDispositivePower>
                         <sharedDispositivePower>3285293.00</sharedDispositivePower>
             </reportingPersonBeneficiallyOwnedNumberOfShares>

              <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>3285293.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>


     	    <classPercent>6.1</classPercent>










	        <typeOfReportingPerson>IN</typeOfReportingPerson>




    </coverPageHeaderReportingPersonDetails>

    <items>
      <item1>
        <issuerName>Upstream Bio, Inc. </issuerName>
        <issuerPrincipalExecutiveOfficeAddress>890 Winter Street, Suite 200, Waltham, MA, 02451.</issuerPrincipalExecutiveOfficeAddress>
      </item1>

      <item2>
        <filingPersonName>The names of the persons filing this report (collectively, the "Reporting Persons") are:

Decheng Capital Global Life Sciences Fund IV, L.P. ("Fund IV")
Decheng Capital Management IV (Cayman), LLC ("GP IV")
Decheng Capital Global Healthcare Fund (Master), LP ("Healthcare")
Decheng Capital Global Healthcare GP, LLC ("Healthcare GP")
Xiangmin Cui ("Dr. Cui")

The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G.</filingPersonName>        <principalBusinessOfficeOrResidenceAddress>3000 Sand Hill Road, Building 2, Suite 110
Menlo Park, CA 94025</principalBusinessOfficeOrResidenceAddress>        <citizenship>Fund IV			Cayman Islands
GP IV			Cayman Islands
Healthcare 		Cayman Islands
Healthcare GP	Cayman Islands
Dr. Cui		 	United States 	</citizenship>      </item2>

        <item3>
		        <notApplicableFlag>Y</notApplicableFlag>

      </item3>



    <item4>
    <amountBeneficiallyOwned>Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference.

The Reporting Persons' ownership of the Issuer's securities consists of (i) 3,085,293 shares of common stock held directly by Fund IV and (ii) 200,000 shares of common stock held directly by Healthcare. GP IV is the general partner of Fund IV and shares voting and investment authority over the shares held by Fund IV. Healthcare GP is the general partner of Healthcare and shares voting and investment authority over the shares held by Healthcare.  Dr. Cui is the manager of GP IV and the indirect managing member and ultimate beneficial owner of Healthcare GP. Dr. Cui shares voting and investment authority over the shares held by each of Fund IV and Healthcare.</amountBeneficiallyOwned>    <classPercent>Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of the securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference. The percentage set forth in each row 11 is based upon 53,596,601 shares of the Issuer's common stock outstanding as of November 5, 2024, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on November 7, 2024.</classPercent>
      <numberOfSharesPersonHas>
        <solePowerOrDirectToVote>Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference.</solePowerOrDirectToVote>
        <sharedPowerOrDirectToVote>Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference.</sharedPowerOrDirectToVote>
        <solePowerOrDirectToDispose>Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference.</solePowerOrDirectToDispose>
        <sharedPowerOrDirectToDispose>Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of December 31, 2024 and is incorporated by reference.</sharedPowerOrDirectToDispose>
      </numberOfSharesPersonHas>
    </item4>


        <item5>
	          <notApplicableFlag>Y</notApplicableFlag>


    </item5>


        <item6>
	  	  <notApplicableFlag>Y</notApplicableFlag>
		        </item6>


        <item7>
	  	  <notApplicableFlag>Y</notApplicableFlag>


    </item7>


          <item8>
                <notApplicableFlag>Y</notApplicableFlag>

              </item8>


            <item9>
                <notApplicableFlag>Y</notApplicableFlag>
                      </item9>


      <item10>
                    <notApplicableFlag>Y</notApplicableFlag>

      </item10>
    </items>

		<exhibitInfo>Exhibit 99.1	Joint Filing Agreement</exhibitInfo>

	    <signatureInformation>
      <reportingPersonName>Decheng Capital Global Life Sciences Fund IV, L.P.</reportingPersonName>

      <signatureDetails>
        <signature>/s/ Xiangmin Cui </signature>
        <title>By Decheng Capital Management IV (Cayman), LLC, its General Partner, By Xiangmin Cui, Manager</title>
        <date>02/14/2025</date>
      </signatureDetails>

    </signatureInformation>
	     <signatureInformation>
      <reportingPersonName>Decheng Capital Management IV (Cayman), LLC</reportingPersonName>

      <signatureDetails>
        <signature>/s/ Xiangmin Cui </signature>
        <title>By Xiangmin Cui, Manager</title>
        <date>02/14/2025</date>
      </signatureDetails>

    </signatureInformation>
	     <signatureInformation>
      <reportingPersonName>Decheng Capital Global Healthcare Fund (Master), LP </reportingPersonName>

      <signatureDetails>
        <signature>/s/ Xiangmin Cui </signature>
        <title>By Decheng Capital Global Healthcare GP, LLC, its General Partner, By Decheng Capital LLC, its Manager, By Xiangmin Cui, Manager</title>
        <date>02/14/2025</date>
      </signatureDetails>

    </signatureInformation>
	     <signatureInformation>
      <reportingPersonName>Decheng Capital Global Healthcare GP, LLC </reportingPersonName>

      <signatureDetails>
        <signature>/s/ Xiangmin Cui </signature>
        <title>By Decheng Capital LLC, its Manager, By Xiangmin Cui, Manager</title>
        <date>02/14/2025</date>
      </signatureDetails>

    </signatureInformation>
	     <signatureInformation>
      <reportingPersonName>Xiangmin Cui</reportingPersonName>

      <signatureDetails>
        <signature>/s/ Xiangmin Cui </signature>
        <title>Xiangmin Cui </title>
        <date>02/14/2025</date>
      </signatureDetails>

    </signatureInformation>



  </formData>


    </edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>2
<FILENAME>ex-99-02142025_100239.htm
<DESCRIPTION>JOINT FILING AGREEMENT
<TEXT>
<!DOCTYPE html PUBLIC "-//IETF//DTD HTML//EN">
<html><head><title>ex-99-02142025_100239.htm</title></head><body style="margin-top:0;font-family:Times New Roman; font-size:10pt; color:#000000">
<p style="margin:0px; padding-left:60px" align="center">EXHIBIT 99.1</p>
<p style="margin:0px" align="center"><br></p>
<p style="margin:0px; padding-left:60px" align="center">JOINT FILING AGREEMENT</p>
<p style="margin:0px" align="center"><br></p>
<p style="margin:0px">The undersigned hereby agree that a single Schedule 13G (or any amendment thereto) relating to the common stock of Upstream Bio, Inc. shall be filed on behalf of each of the undersigned and that this Agreement shall be filed as an exhibit to such Schedule 13G.</p>
<p style="margin:0px"><br></p>
<p style="margin:0px">Dated: &nbsp;February 14, 2025</p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><b>Decheng Capital Global Life Sciences Fund IV, L.P.</b></p>
<p style="margin:0px"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px">Decheng Capital Management IV (Cayman), LLC</p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; clear:left; float:left">Its:</p>
<p style="margin:0px; text-indent:-2px">&nbsp;General Partner</p>
<p style="margin:0px; clear:left"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px"><u>/s/ Xiangmin Cui</u></p>
<p style="margin:0px; clear:left">Name: &nbsp;Xiangmin Cui</p>
<p style="margin:0px">Title: &nbsp;Manager</p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><b>Decheng Capital Management IV (Cayman), LLC</b></p>
<p style="margin:0px"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px"><u>/s/ Xiangmin Cui</u></p>
<p style="margin:0px; clear:left">Name: &nbsp;Xiangmin Cui</p>
<p style="margin:0px">Title: &nbsp;Manager</p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><b>Decheng Capital Global Healthcare Fund (Master), LP </b></p>
<p style="margin:0px"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px">Decheng Capital Global Healthcare GP, LLC</p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; clear:left; float:left">Its:</p>
<p style="margin:0px; text-indent:-2px">&nbsp;General Partner</p>
<p style="margin:0px; clear:left"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px">Decheng Capital LLC</p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; clear:left; float:left">Its:</p>
<p style="margin:0px; text-indent:-2px">Manager</p>
<p style="margin:0px; clear:left"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px"><u>/s/ Xiangmin Cui</u></p>
<p style="margin:0px; clear:left">Name: &nbsp;Xiangmin Cui</p>
<p style="margin:0px">Title: &nbsp;Manager</p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><b>Decheng Capital Global Healthcare GP, LLC</b></p>
<p style="margin:0px"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px">Decheng Capital LLC</p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; clear:left; float:left">Its:</p>
<p style="margin:0px; text-indent:-2px">Manager</p>
<p style="margin:0px; clear:left"><br></p>
<p style="margin-top:0px; margin-bottom:-2px; width:30px; float:left">By:</p>
<p style="margin:0px; text-indent:-2px"><u>/s/ Xiangmin Cui</u></p>
<p style="margin:0px; clear:left">Name: &nbsp;Xiangmin Cui</p>
<p style="margin:0px">Title: &nbsp;Manager</p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><b>Xiangmin Cui</b></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><u>/s/ Xiangmin Cui</u></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><br></p>
<p style="margin:0px"><br></p>
</body></html>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
