-----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,
 B4EWHJxn0I79hklsGDD5Ew/+dYLGJOlSvXQmPtwyCeP8bUz0CKXBymd/vzlHdDIj
 6va1Q18gHBwyTUWwfBZNKg==

<SEC-DOCUMENT>0000895345-09-000739.txt : 20090731
<SEC-HEADER>0000895345-09-000739.hdr.sgml : 20090731
<ACCEPTANCE-DATETIME>20090731174910
ACCESSION NUMBER:		0000895345-09-000739
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090731
FILED AS OF DATE:		20090731
DATE AS OF CHANGE:		20090731

REPORTING-OWNER:	

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

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17999
		FILM NUMBER:		09978385

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

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:		830 WINTER ST
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		(781)895-0600

	MAIL ADDRESS:	
		STREET 1:		830 WINTER ST
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SAMANA CAPITAL, L.P.
		CENTRAL INDEX KEY:			0001054458

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17999
		FILM NUMBER:		09978387

	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

	FORMER NAME:	
		FORMER CONFORMED NAME:	ZIFF ASSET MANAGEMENT LP
		DATE OF NAME CHANGE:	19980204

REPORTING-OWNER:	

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

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-17999
		FILM NUMBER:		09978386

	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

	FORMER NAME:	
		FORMER CONFORMED NAME:	PBK HOLDINGS INC
		DATE OF NAME CHANGE:	19980416
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>ja4-immunogen_samanaex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-07-31</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001054458</rptOwnerCik>
            <rptOwnerName>SAMANA CAPITAL, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>283 GREENWICH AVENUE</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>MORTON 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>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-07-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3500000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.64</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5525200</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This statement is being filed by Samana Capital, L.P. (&quot;Samana Capital&quot;), Morton Holdings, Inc. (&quot;Morton Holdings&quot;) and
 Philip B. Korsant (&quot;Korsant&quot; and collectively  with Samana Capital and Morton Holdings, the &quot;Reporting Persons&quot;).  Morton
 Holdings is the general partner of Samana Capital.  Korsant is the sole shareholder of Morton Holdings.
(Due to SEC formatting limitations, please see continuation in footnote 2)</footnote>
        <footnote id="F2">(Continued from footnote 1)
Samana Capital is the owner of record of all of the shares of ImmunoGen, Inc. common stock, par value $0.01 per share
 (&quot;Common Stock&quot;), reported above.  The Reporting Persons may each be deemed to have or share voting or investment power over
 4,312,500 shares of the Common Stock reported in Column 5 above, but do not have or share voting or investment power above
 the remaining 1,212,700 shares of Common Stock reported in Column 5 above.  Each of the Reporting Persons disclaims
 beneficial ownership of the shares of Common Stock reported herein, except to the extent of its respective pecuniary
 interests.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>SAMANA CAPITAL, L.P., By: Morton Holdings, Inc., its general partner, By: /s/ Catherine O'Dwyer, Vice President of Morton Holdings, Inc.</signatureName>
        <signatureDate>2009-07-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MORTON HOLDINGS, INC., By: /s/ Catherine O'Dwyer, Vice President of Morton Holdings, Inc.</signatureName>
        <signatureDate>2009-07-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Philip B. Korsant</signatureName>
        <signatureDate>2009-07-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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