Immunogen (IMGN) 10-Q/A 2006 Q1 Quarterly report (amended)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q/A

Amendment No. 1

ý QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES

EXCHANGE ACT OF 1934

For the quarterly period ended September 30, 2005

OR

o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES

EXCHANGE ACT OF 1934

For the transition period from            to

Commission file number 0-17999

ImmunoGen, Inc.

Massachusetts	04-2726691
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
128 Sidney Street, Cambridge, MA 02139
(Address of principal executive offices, including zip code)
(617) 995-2500
(Registrant’s telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

YesýNoo

Indicate by check mark whether the registrant is an accelerated filer (as defined in Rule 12b-2 of the Exchange Act).

YesýNoo

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

YesoNoý

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date.

Shares of common stock, par value $.01 per share: 41,077,428 shares outstanding as of November 4, 2005

EXPLANATORY NOTE

This Amendment No. 1 to the Form 10-Q for the quarterly period ended September 30, 2005 for ImmunoGen, Inc. is being filed solely for the purpose of filing corrected versions of Exhibits 31.1 and 31.2 in order to correct clerical omissions in each.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	ImmunoGen, Inc.
Date: November 16, 2005	By:	/s/ Mitchel Sayare
		Mitchel Sayare
		President and Chief Executive Officer (principal executive officer)
Date: November 16, 2005	By:	/s/ Daniel M. Junius
		Daniel M. Junius
		Senior Vice President and Chief Financial Officer (principal financial officer)

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