<SEC-DOCUMENT>0000950170-24-106072.txt : 20240912
<SEC-HEADER>0000950170-24-106072.hdr.sgml : 20240912
<ACCEPTANCE-DATETIME>20240912191444
ACCESSION NUMBER:		0000950170-24-106072
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240912
FILED AS OF DATE:		20240912
DATE AS OF CHANGE:		20240912

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ORBIMED ADVISORS LLC
		CENTRAL INDEX KEY:			0001055951
		ORGANIZATION NAME:           	
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42272
		FILM NUMBER:		241296069

	BUSINESS ADDRESS:	
		STREET 1:		601 LEXINGTON AVENUE
		STREET 2:		54TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		(212) 739-6400

	MAIL ADDRESS:	
		STREET 1:		601 LEXINGTON AVENUE
		STREET 2:		54TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			OrbiMed Genesis GP LLC
		CENTRAL INDEX KEY:			0001808744
		ORGANIZATION NAME:           	
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42272
		FILM NUMBER:		241296067

	BUSINESS ADDRESS:	
		STREET 1:		601 LEXINGTON AVENUE, 54TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		(212) 739-6400

	MAIL ADDRESS:	
		STREET 1:		601 LEXINGTON AVENUE, 54TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			OrbiMed Capital GP VII LLC
		CENTRAL INDEX KEY:			0001760648
		ORGANIZATION NAME:           	
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42272
		FILM NUMBER:		241296068

	BUSINESS ADDRESS:	
		STREET 1:		601 LEXINGTON AVENUE, 54TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-739-6491

	MAIL ADDRESS:	
		STREET 1:		601 LEXINGTON AVENUE, 54TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MBX Biosciences, Inc.
		CENTRAL INDEX KEY:			0001776111
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		12406 HORESHAM STREET
		CITY:			CARMEL
		STATE:			IN
		ZIP:			46032
		BUSINESS PHONE:		3179893100

	MAIL ADDRESS:	
		STREET 1:		12406 HORESHAM STREET
		CITY:			CARMEL
		STATE:			IN
		ZIP:			46032
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>ownership.xml
<DESCRIPTION>3
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2024-09-12</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001776111</issuerCik>
        <issuerName>MBX Biosciences, Inc.</issuerName>
        <issuerTradingSymbol>MBX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001055951</rptOwnerCik>
            <rptOwnerName>ORBIMED ADVISORS LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>601 LEXINGTON AVENUE, 54TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001760648</rptOwnerCik>
            <rptOwnerName>OrbiMed Capital GP VII LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>601 LEXINGTON AVENUE, 54TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001808744</rptOwnerCik>
            <rptOwnerName>OrbiMed Genesis GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>601 LEXINGTON AVENUE, 54TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series A Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1029157</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By OrbiMed Private Investments VII, LP</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series B Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1629271</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By OrbiMed Private Investments VII, LP</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series C Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>403787</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By OrbiMed Genesis Master Fund, L.P.</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each share of Series A Convertible Preferred Stock, Series B Convertible Preferred Stock, and Series C Convertible Preferred Stock (collectively, the &quot;Preferred Stock&quot;) is convertible into Common Stock on a one-for-12.0221 basis at any time at the option of the holder, and will automatically convert into the number of shares shown in Column 3 immediately prior to the closing of the Issuer's initial public offering. The Preferred Stock has no expiration date.</footnote>
        <footnote id="F2">These securities are held of record by OrbiMed Private Investments VII, LP (&quot;OPI VII&quot;). OrbiMed Capital GP VII LLC (&quot;GP VII&quot;) is the general partner of OPI VII. OrbiMed Advisors LLC (&quot;OrbiMed Advisors&quot;) is the managing member of GP VII. By virtue of such relationship, OrbiMed Advisors and GP VII may be deemed to have voting power and investment power over the securities held by OPI VII and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VII.</footnote>
        <footnote id="F3">These securities are held of record by OrbiMed Genesis Master Fund, L.P. (&quot;Genesis Master Fund&quot;). OrbiMed Genesis GP LLC (&quot;Genesis GP&quot;) is the general partner of Genesis Master Fund. OrbiMed Advisors is the managing member of Genesis GP. By virtue of such relationship, OrbiMed Advisors and Genesis GP may be deemed to have voting power and investment power over the securities held by Genesis Master Fund and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by Genesis Master Fund.</footnote>
        <footnote id="F4">This report on Form 3 is jointly filed by OrbiMed Advisors, GP VII, and Genesis GP. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the &quot;Exchange Act&quot;), except to the extent of its pecuniary interest therein, if any. OrbiMed Advisors has designated a representative, Carl L. Gordon, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purpose of Section 16 of the Exchange Act, or for any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>OrbiMed Advisors LLC, By: /s/ Douglas Coon, Chief Compliance Officer</signatureName>
        <signatureDate>2024-09-12</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>OrbiMed Capital GP VII LLC, By: /s/ Douglas Coon, Chief Compliance Officer</signatureName>
        <signatureDate>2024-09-12</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>OrbiMed Genesis GP LLC, By: /s/ Douglas Coon, Chief Compliance Officer</signatureName>
        <signatureDate>2024-09-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
