-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000918923-09-000007.txt : 20090708
<SEC-HEADER>0000918923-09-000007.hdr.sgml : 20090708
<ACCEPTANCE-DATETIME>20090708181656
ACCESSION NUMBER:		0000918923-09-000007
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090706
FILED AS OF DATE:		20090708
DATE AS OF CHANGE:		20090708

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LAMPERT MARK N
		CENTRAL INDEX KEY:			0001233840

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		09935824

	MAIL ADDRESS:	
		STREET 1:		2415 GREEN ST
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94123

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			REPLIGEN CORP
		CENTRAL INDEX KEY:			0000730272
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				042729386
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		41 SEYON STREET
		STREET 2:		BUILDING 1, SUITE 100
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02453
		BUSINESS PHONE:		7814499560

	MAIL ADDRESS:	
		STREET 1:		41 SEYON STREET
		STREET 2:		BUILDING 1, SUITE 100
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02453

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BIOTECHNOLOGY VALUE FUND L P
		CENTRAL INDEX KEY:			0000918923
		STANDARD INDUSTRIAL CLASSIFICATION:	INVESTMENT ADVICE [6282]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		09935827

	BUSINESS ADDRESS:	
		STREET 1:		900 N. MICHIGAN AVENUE, SUITE 1100
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611
		BUSINESS PHONE:		3125066500

	MAIL ADDRESS:	
		STREET 1:		900 N. MICHIGAN AVENUE, SUITE 1100
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BVF PARTNERS L P/IL
		CENTRAL INDEX KEY:			0001055947

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		09935828

	BUSINESS ADDRESS:	
		STREET 1:		ONE SANSOME ST
		STREET 2:		39TH FL
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104
		BUSINESS PHONE:		3125066500

	MAIL ADDRESS:	
		STREET 1:		900 N. MICHIGAN AVENUE
		STREET 2:		SUITE 1100
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BVF INC/IL
		CENTRAL INDEX KEY:			0001056807
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		09935823

	BUSINESS ADDRESS:	
		STREET 1:		ONE SANSOME ST
		STREET 2:		39TH FLOOR
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104
		BUSINESS PHONE:		3125066500

	MAIL ADDRESS:	
		STREET 1:		C/O GROSVENOR CAPITAL MANAGEMENT
		STREET 2:		900 N. MICHIGAN AVENUE, SUITE 1100
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BIOTECHNOLOGY VALUE FUND II LP
		CENTRAL INDEX KEY:			0001102444
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		09935826

	BUSINESS ADDRESS:	
		STREET 1:		ONE SANSOME ST
		STREET 2:		39TH FL.
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104
		BUSINESS PHONE:		3125066500

	MAIL ADDRESS:	
		STREET 1:		C/O GROSVENOR CAPITAL MANAGEMENT
		STREET 2:		900 N. MICHIGAN AVENUE, SUITE 1100
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BVF INVESTMENTS LLC
		CENTRAL INDEX KEY:			0001132245
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		09935825

	BUSINESS ADDRESS:	
		STREET 1:		ONE SANSOME ST. 39TH FL
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94104
		BUSINESS PHONE:		3125066500

	MAIL ADDRESS:	
		STREET 1:		C/O GROSVENOR CAPITAL MANAGEMENT LP
		STREET 2:		900 N. MICHIGAN AVENUE, SUITE 1100
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611
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    <reportingOwner>
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    <reportingOwner>
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            <rptOwnerStreet2></rptOwnerStreet2>
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    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
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            <rptOwnerName>BVF INVESTMENTS LLC</rptOwnerName>
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        <reportingOwnerAddress>
            <rptOwnerStreet1>900 N. MICHIGAN AVE., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60611</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001233840</rptOwnerCik>
            <rptOwnerName>LAMPERT MARK N</rptOwnerName>
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        <reportingOwnerAddress>
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            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60611</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Indirect Beneficial Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001056807</rptOwnerCik>
            <rptOwnerName>BVF INC/IL</rptOwnerName>
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        <reportingOwnerAddress>
            <rptOwnerStreet1>900 N. MICHIGAN AVE., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60611</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
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    </reportingOwner>

    <nonDerivativeTable>
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            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
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            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <transactionPricePerShare>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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        </nonDerivativeTransaction>
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            <transactionCoding>
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                    <value>5.5157</value>
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            <postTransactionAmounts>
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            <transactionDate>
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                <transactionPricePerShare>
                    <value>5.50</value>
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                <transactionAcquiredDisposedCode>
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                    <value>2765050</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>General partner and manager of entities with direct ownership.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
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                <sharesOwnedFollowingTransaction>
                    <value>2765050</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F6"/>
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                <natureOfOwnership>
                    <value>General Partner of entity with indirect ownership.</value>
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        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2765050</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F7"/>
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                <natureOfOwnership>
                    <value>Sole shareholder and sole director of entity with indirect ownership.</value>
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    <footnotes>
        <footnote id="F1">Units may represent aggregation of daily trade activity.  Details regarding individual execution amounts and prices are available upon request.</footnote>
        <footnote id="F2">Shares directly beneficially owned by Biotechnology Value Fund, L.P. (&quot;BVF&quot;)</footnote>
        <footnote id="F3">Shares directly beneficially owned by Biotechnology Value Fund II, L.P. (&quot;BVF II&quot;)</footnote>
        <footnote id="F4">The shares of Common Stock are directly beneficially owned by BVF Investments, LLC (&quot;BVFLLC&quot;), a Delaware limited liability company.  Pursuant to the operating agreement of BVFLLC, BVF Partners, L.P., a Delaware limited partnership (&quot;Partners&quot;) is authorized, among other things, to invest the contributed capital of Samana Capital, L.P., the majority member of BVFLLC, in the shares of Common Stock and other securities and to vote, exercise or convert and dispose of such securities and is entitled to receive fees based on assets under management and, subject to certain exceptions, allocations  based on realized and unrealized gains on such assets.</footnote>
        <footnote id="F5">The shares of Common Stock are indirectly beneficially owned by Partners.  Partners is the general partner of BVF and BVF II and is the manager of BVFLLC.</footnote>
        <footnote id="F6">The shares of Common Stock are indirectly beneficially owned by BVF Inc., a Delaware corporation (&quot;BVF Inc.&quot;).  BVF Inc. is the general partner of Partners.</footnote>
        <footnote id="F7">Mark N. Lampert is the sole shareholder, sole director, and an officer of BVF Inc.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>BVF Partners L.P., By: BVF Inc., its GP, By: /s/ Mark N. Lampert</signatureName>
        <signatureDate>2009-07-08</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>BIOTECHNOLOGY VALUE FUND, L.P. By: BVF Partners L.P., its GP, By: BVF Inc., By: /s/ Mark N. Lampert</signatureName>
        <signatureDate>2009-07-08</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>BIOTECHNOLOGY VALUE FUND II, L.P., By: BVF Partners L.P., its GP, By: BVF Inc., By: /s/ Mark N. Lampert</signatureName>
        <signatureDate>2009-07-08</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>BVF INVESTMENTS, L.L.C., By: BVF Partners L.P., its Manager, By: BVF Inc., By: /s/ Mark N. Lampert</signatureName>
        <signatureDate>2009-07-08</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>BVF INC., By: /s/ Mark N. Lampert</signatureName>
        <signatureDate>2009-07-08</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MARK N. LAMPERT By: /s/ Mark N. Lampert</signatureName>
        <signatureDate>2009-07-08</signatureDate>
    </ownerSignature>
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-----END PRIVACY-ENHANCED MESSAGE-----
