-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 RnEzfyywFbpKv5/N2rjGMw==

<SEC-DOCUMENT>0001209191-08-038435.txt : 20080623
<SEC-HEADER>0001209191-08-038435.hdr.sgml : 20080623
<ACCEPTANCE-DATETIME>20080623181309
ACCESSION NUMBER:		0001209191-08-038435
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080619
FILED AS OF DATE:		20080623
DATE AS OF CHANGE:		20080623

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPM BIOVENTURES I LP
		CENTRAL INDEX KEY:			0001263199

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913062

	BUSINESS ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6174259200

	MAIL ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER NAME:	
		FORMER CONFORMED NAME:	MPM BIO VENTURES I LP
		DATE OF NAME CHANGE:	20030910

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GADICKE ANSBERT
		CENTRAL INDEX KEY:			0001134655

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913063

	BUSINESS ADDRESS:	
		STREET 1:		ONE CAMBRIDGE CENTER
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		6174259200

	MAIL ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPM BIOVENTURES PARALLEL FUND L P
		CENTRAL INDEX KEY:			0001067661

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913066

	BUSINESS ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		61724259200

	MAIL ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER NAME:	
		FORMER CONFORMED NAME:	MPM BIO VENTURES PARALLEL FUND L P
		DATE OF NAME CHANGE:	19980805

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPM ASSET MANAGEMENT INVESTORS 1999 LLC
		CENTRAL INDEX KEY:			0001264820
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913067

	BUSINESS ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6174259200

	MAIL ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BAB BIO VENTURES NV
		CENTRAL INDEX KEY:			0001263198

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913068

	MAIL ADDRESS:	
		STREET 1:		111 HUNTINGTON AVE
		STREET 2:		31ST FL
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02199

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BAB BIO VENTURES LLP
		CENTRAL INDEX KEY:			0001263197

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913069

	BUSINESS ADDRESS:	
		STREET 1:		111 HUNTINGTON AVE
		STREET 2:		31ST FL
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02199
		BUSINESS PHONE:		6174259200

	MAIL ADDRESS:	
		STREET 1:		111 HUNTINGTON AVE
		STREET 2:		31ST FL
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02199

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MPM BIO VENTURES I LLC
		CENTRAL INDEX KEY:			0001263200

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913065

	BUSINESS ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6174259200

	MAIL ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Pharmasset Inc
		CENTRAL INDEX KEY:			0001301081
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000

	BUSINESS ADDRESS:	
		STREET 1:		303-A COLLEGE ROAD EAST
		CITY:			PRINCETON
		STATE:			NJ
		ZIP:			08540
		BUSINESS PHONE:		609-613-4100

	MAIL ADDRESS:	
		STREET 1:		303-A COLLEGE ROAD EAST
		CITY:			PRINCETON
		STATE:			NJ
		ZIP:			08540

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STEINMETZ MICHAEL
		CENTRAL INDEX KEY:			0001166285

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913064

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		6174259200

	MAIL ADDRESS:	
		STREET 1:		THE JOHN HANCOCK TOWER
		STREET 2:		200 CLARENDON STREET, 54TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BB BIOVENTURES L P
		CENTRAL INDEX KEY:			0001040662

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33428
		FILM NUMBER:		08913070

	BUSINESS ADDRESS:	
		STREET 1:		62 DE RUYTURES
		CITY:			CURACAO NETHERLANDS ANTILLES
		STATE:			P8

	MAIL ADDRESS:	
		STREET 1:		111 HUNTINGTON AVE 31ST FL
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02119
</SEC-HEADER>
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<SEQUENCE>1
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<DESCRIPTION>MAIN DOCUMENT DESCRIPTION
<TEXT>
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    <periodOfReport>2008-06-19</periodOfReport>

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        <issuerName>Pharmasset Inc</issuerName>
        <issuerTradingSymbol>VRUS</issuerTradingSymbol>
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    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001040662</rptOwnerCik>
            <rptOwnerName>BB BIOVENTURES L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001263197</rptOwnerCik>
            <rptOwnerName>BAB BIO VENTURES LLP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001263198</rptOwnerCik>
            <rptOwnerName>BAB BIO VENTURES NV</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <otherText>Former 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001264820</rptOwnerCik>
            <rptOwnerName>MPM ASSET MANAGEMENT INVESTORS 1999 LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
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            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001067661</rptOwnerCik>
            <rptOwnerName>MPM BIOVENTURES PARALLEL FUND L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001263199</rptOwnerCik>
            <rptOwnerName>MPM BIOVENTURES I LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
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            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001263200</rptOwnerCik>
            <rptOwnerName>MPM BIO VENTURES I LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001166285</rptOwnerCik>
            <rptOwnerName>STEINMETZ MICHAEL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON STREET, 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001134655</rptOwnerCik>
            <rptOwnerName>GADICKE ANSBERT</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MPM ASSET MANAGEMENT</rptOwnerStreet1>
            <rptOwnerStreet2>200 CLARENDON ST., 54TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-06-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>153700</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.9</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2120431</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-06-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>500</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.91</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2119931</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-06-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.92</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2119831</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-06-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                    <footnoteId id="F7"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.94</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2119731</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F8"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-06-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1400</value>
                    <footnoteId id="F9"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2118331</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares were sold as follows:   68,391 shares by BB BioVentures, L.P. (&quot;BBBV&quot;), 9,220 shares by MPM BioVentures Parallel Fund, L.P. (&quot;BV PF&quot;), 815 shares by MPM Asset Management Investors 1999 LLC (&quot;AM 1999&quot;), 3,971 shares by MPM BioVentures III, L.P., (&quot;BV III&quot;), 59,073 shares by MPM BioVentures III-QP, L.P. (&quot;BV III QP&quot;), 4,993 shares held by MPM BioVentures III GmbH &amp; Co. Beteiligungs KG (&quot;BV KG&quot;), 1,785 shares by MPM BioVentures III Parallel Fund, L.P. (&quot;BV III PF&quot;), 1,403 shares held by MPM Asset Management Investors 2004 BVIII LLC (&quot;AM BV III&quot;), 3,949 by MPM BioVentures III GP, LP (&quot;BV III GP&quot;) and 100 by MPM Capital, L.P. (&quot;MPM LP&quot;).      MPM BioVentures I, L.P. (&quot;BV I&quot;) and MPM BioVentures I LLC (&quot;BV I LLC&quot;) are the direct and indirect general partners of BV PF. BAB BioVentures L.P. (&quot;BAB BV&quot;), BAB BioVentures, N.V. (&quot;BAB NV&quot;) a
nd BV I LLC are the direct and indirect general partners of BBBV. Michael Steinmetz and Ansbert Gadicke are  managers of AM 1999 and BV I LLC.  BV III GP and MPM BioVentures III LLC (&quot;BV III LLC&quot;) are the direct and indirect general partners of BV III, BV III QP, BV III PF and BV KG.   Michael Steinmetz and Ansbert Gadicke are Series A members of BV III LLC and managers of AM BV III.   Ansbert Gadicke has a controlling interest in MPM LP.  Each Reporting Person disclaims beneficial ownership of all such shares except to the extent of their respective proportionate pecuniary interests therein.</footnote>
        <footnote id="F2">The shares are held as follows:  943,507 by BBBV, 127,194 by BV PF, 11,251 by AM 1999, 54,801 by BV III, 814,953 by BV III QP, 68,868 by BV KG, 24,612 by BV III PF, 19,374 by AM BV III, 54,502 by BV III GP and 1,369 by MPM LP.    Each Reporting Person disclaims beneficial ownership of the securities except to the extent of their respective proportionate pecuniary interest therein.</footnote>
        <footnote id="F3">The shares were sold as follows:   222 by BBBV, 30 by BV PF, 3 by AM 1999, 13 by BV III, 192 by BV III QP, 16 by BV KG, 6 by BV III PF, 5 by AM BV III and 13 by BV III GP.</footnote>
        <footnote id="F4">The shares are held as follows:  943,285 by BBBV, 127,164 by BV PF, 11,248 by AM 1999, 54,788 by BV III, 814,761 by BV III QP, 68,852 by BV KG, 24,606 by BV III PF, 19,369 by AM BV III, 54,489 by BV III GP and 1,369 by MPM LP.    Each Reporting Person disclaims beneficial ownership of the securities except to the extent of their respective proportionate pecuniary interest therein.</footnote>
        <footnote id="F5">The shares were sold as follows:   44 by BBBV, 6 by BV PF, 1 by AM 1999, 3 by BV III, 38 by BV III QP, 3 by BV KG, 1 by BV III PF, 1 by AM BV III and 3 by BV III GP.</footnote>
        <footnote id="F6">The shares are held as follows:  943,241 by BBBV, 127,158 by BV PF, 11,247 by AM 1999, 54,785 by BV III, 814,723 by BV III QP, 68,849 by BV KG, 24,605 by BV III PF, 19,368 by AM BV III, 54,486 by BV III GP and 1,369 by MPM LP.    Each Reporting Person disclaims beneficial ownership of the securities except to the extent of their respective proportionate pecuniary interest therein.</footnote>
        <footnote id="F7">The shares were sold as follows:   44 by BBBV, 6 by BV PF, 1 by AM 1999, 3 by BV III, 38 by BV III QP, 3 by BV KG, 1 by BV III PF, 1 by AM BV III and 3 by BV III GP.</footnote>
        <footnote id="F8">The shares are held as follows:  943,197 by BBBV, 127,152 by BV PF, 11,246 by AM 1999, 54,782 by BV III, 814,685 by BV III QP, 68,846 by BV KG, 24,604 by BV III PF, 19,367 by AM BV III, 54,483 by BV III GP and 1,369 by MPM LP.    Each Reporting Person disclaims beneficial ownership of the securities except to the extent of their respective proportionate pecuniary interest therein.</footnote>
        <footnote id="F9">The shares were sold as follows:   624 by BBBV, 84 by BV PF, 7 by AM 1999, 36 by BV III, 538 by BV III QP, 45 by BV KG, 16 by BV III PF, 13 by AM BV III, 36 by BV III GP and 1 by MPM LP.</footnote>
        <footnote id="F10">The shares are held as follows:  942,573 by BBBV, 127,068 by BV PF, 11,239 by AM 1999, 54,746 by BV III, 814,147 by BV III QP, 68,801 by BV KG, 24,588 by BV III PF, 19,354 by AM BV III, 54,447 by BV III GP and 1,368 by MPM LP.    Each Reporting Person disclaims beneficial ownership of the securities except to the extent of their respective proportionate pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By Ansbert Gadicke, managing director of BAB BioVentures NV, the general partner of BAB BioVentures L.P., the general partner of BB BioVentures L.P. /s/ Ansbert Gadicke</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Ansbert Gadicke, managing director of BAB BioVentures NV, the general partner of BAB BioVentures L.P.   /s/ Ansbert Gadicke</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Ansbert Gadicke, managing director of BAB BioVentures NV  /s/ Ansbert Gadicke</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Luke Evnin, manager of MPM Asset Management Investors 1999 LLC /s/ Luke Evnin</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Luke Evnin, manager of MPM BioVentures I LLC, the general partner of MPM BioVentures I L.P., the general partner of MPM BioVentures Parallel Fund, L.P. /s/ Luke Evnin</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Luke Evnin, manager of MPM BioVentures I LLC, the general partner of MPM BioVentures I L.P.  /s/ Luke Evnin</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By Luke Evnin, manager of MPM BioVentures I LLC /s/ Luke Evnin</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Michael Steinmetz</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Ansbert Gadicke</signatureName>
        <signatureDate>2008-06-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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