-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 M6/pHwAsoL4qAQTgVGVkQaZ5q2pUE5sWYcx20nv3b3EJPp5z1c+VgbKSRZVGhFWT
 2uAg5cpmTqw2LkkOjqTQDg==

<SEC-DOCUMENT>0000895345-08-000392.txt : 20080630
<SEC-HEADER>0000895345-08-000392.hdr.sgml : 20080630
<ACCEPTANCE-DATETIME>20080630113250
ACCESSION NUMBER:		0000895345-08-000392
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080620
FILED AS OF DATE:		20080630
DATE AS OF CHANGE:		20080630

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IMMUNOGEN INC
		CENTRAL INDEX KEY:			0000855654
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				042726691
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		128 SIDNEY ST
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		6179952506

	MAIL ADDRESS:	
		STREET 1:		128 SIDNEY ST
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KORSANT PHILIP B
		CENTRAL INDEX KEY:			0001271455

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17999
		FILM NUMBER:		08924517

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		2036227112

	MAIL ADDRESS:	
		STREET 1:		283 GREENWICH AVE
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PBK HOLDINGS INC
		CENTRAL INDEX KEY:			0001059932
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17999
		FILM NUMBER:		08924518

	BUSINESS ADDRESS:	
		STREET 1:		283 GREENWICH AVE
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		2036227112

	MAIL ADDRESS:	
		STREET 1:		283 GREENWICH AVE
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ZBI Equities, L.L.C.
		CENTRAL INDEX KEY:			0001438572
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17999
		FILM NUMBER:		08924519

	BUSINESS ADDRESS:	
		STREET 1:		283 GREENWICH AVENUE
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		2122926658

	MAIL ADDRESS:	
		STREET 1:		350 PARK AVENUE
		STREET 2:		11TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ZIFF ASSET MANAGEMENT LP
		CENTRAL INDEX KEY:			0001054458

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17999
		FILM NUMBER:		08924520

	BUSINESS ADDRESS:	
		STREET 1:		153 EAST 53RD STREET 43RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		2122925900

	MAIL ADDRESS:	
		STREET 1:		153 EAST 53RD STREET
		STREET 2:		43RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>jf3-immunogen_ziffex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2008-06-20</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000855654</issuerCik>
        <issuerName>IMMUNOGEN INC</issuerName>
        <issuerTradingSymbol>IMGN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001054458</rptOwnerCik>
            <rptOwnerName>ZIFF ASSET MANAGEMENT LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>283 GREENWICH AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001059932</rptOwnerCik>
            <rptOwnerName>PBK HOLDINGS INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>283 GREENWICH AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001271455</rptOwnerCik>
            <rptOwnerName>KORSANT PHILIP B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>283 GREENWICH AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001438572</rptOwnerCik>
            <rptOwnerName>ZBI Equities, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>283 GREENWICH AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9046200</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This statement is being filed by Ziff Asset Management, L.P. (&quot;Ziff Asset Management&quot;), PBK Holdings, Inc. (&quot;PBK Holdings&quot;),
 Philip B. Korsant (&quot;Korsant&quot;) and ZBI Equities, L.L.C. (&quot;ZBI Equities&quot; and collectively with Ziff Asset Management, PBK
 Holdings and Korsant, the &quot;Reporting Persons.&quot;).  PBK Holdings is the general partner of Ziff Asset Management, Korsant is
 the sole shareholder of PBK Holdings and ZBI Equities assists in the management of certain assets held by Ziff Asset
 Management.</footnote>
        <footnote id="F2">Ziff Asset Management is the record owner of all of the 9,046,200 shares of common stock, par value $.01 per share of
 ImmunoGen, Inc. (the &quot;Common Stock&quot;) reported herein.  The Reporting Persons do not have or share voting or investment power
 over 1,233,700 shares of the Common Stock reported herein and each of the Reporting Persons disclaims beneficial ownership
 of such 1,233,700 shares, except to the extent of its respective pecuniary interests, if any, in such shares.  PBK Holdings,
 Korsant and ZBI Equities may each be deemed to have or share voting or investment power over the remaining 7,812,500 shares
 of Common Stock reported herein.  Each of the Reporting Persons disclaims beneficial ownership of such 7,812,500 shares of
 Common Stock, except to the extent of its respective pecuniary interest, if any, in such 7,812,500 shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ David Gray, Vice President of PBK Holdings, Inc., the general partner of Ziff Asset Management, L.P.</signatureName>
        <signatureDate>2008-06-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ David Gray, Vice President of PBK Holdings, Inc.</signatureName>
        <signatureDate>2008-06-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Philip B. Korsant</signatureName>
        <signatureDate>2008-06-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ David Gray, Vice President of PBK Holdings, Inc., sole member of ZBI Equities, L.L.C.</signatureName>
        <signatureDate>2008-06-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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