UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): January 30, 2012

ImmunoGen, Inc.

(Exact name of registrant as specified in its charter)

830 Winter Street, Waltham, MA 02451

(Address of principal executive offices)   (Zip Code)

Registrant’s telephone number, including area code: (781) 895-0600

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o            Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o            Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o            Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o            Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 5.02 — DEPARTURE OF DIRECTORS OR CERTAIN OFFICERS; ELECTION OF DIRECTORS; APPOINTMENT OF CERTAIN OFFICERS; COMPENSATORY ARRANGEMENTS OF CERTAIN OFFICERS

(a) — (c)  Not applicable.

(d)  On January 30, 2012, the Board of Directors of ImmunoGen, Inc. (the “Company”) voted to expand the size of the Board from eight to ten members, and elected Kristine Peterson and Dean J. Mitchell to fill the newly-created vacancies.  Ms. Peterson will also serve as a member of the Audit Committee of the Board of Directors, and Mr. Mitchell will also serve as a member of the Compensation Committee of the Board of Directors.

A description of the compensation payable to Ms. Peterson and Mr. Mitchell for their service as a director is set forth in the Company’s definitive Proxy Statement dated September 26, 2011, filed with the Securities and Exchange Commission on September 26, 2011, under the caption “Director Compensation,” and is incorporated herein by reference.

(e)  Not applicable.

ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS

(d): The following exhibit is being furnished herewith:

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SIGNATURES

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

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Exhibit 99.1

Contacts

ImmunoGen, Inc. Announces Addition of
Kristine Peterson and Dean Mitchell to its Board of Directors

WALTHAM, MA, January 30, 2012 — ImmunoGen, Inc. (Nasdaq: IMGN), a biotechnology company that develops targeted anticancer therapeutics using its antibody expertise, today announced the addition of Kristine Peterson and Dean Mitchell to the Company’s Board of Directors.

“Both Kris and Dean have more than 25 years of experience in the healthcare industry, including extensive expertise in product development and commercialization,” commented Stephen McCluski, Chairman of the Board. “As ImmunoGen’s product pipeline continues to advance and expand, this expertise has become increasingly important in shaping corporate direction and priorities.”

Ms. Peterson is CEO of Valeritas, Inc., and also a director on its board. She previously was Company Group Chairman, Biotech Business, at Johnson & Johnson, where she was responsible for research, development, manufacturing, and commercialization of oncology, immunology, and other biotechnology therapeutics for the company. Prior to joining J&J in 2004 as Executive VP, Pharmaceutical Group Strategic Marketing, Ms. Peterson had a twenty-year career with Bristol-Myers Squibb, rising through the organization to become Senior VP, Global Marketing before taking Senior VP and President roles at Biovail Corporation in 2003. Ms. Peterson is active in the Biotechnology Industry Organization (BIO) and also serves on the board of Amarin Corporation.

Mr. Mitchell is President and CEO of Lux Biosciences, Inc., and also a director on its board. He previously was President and CEO of Alpharma, Inc. and, before that, of Guilford Pharmaceuticals. Prior to joining Guilford in 2004, Mr. Mitchell held senior-level positions at Bristol-Myers Squibb, including President, International Pharmaceuticals and President, North America Primary Care. Prior to joining Bristol-Myers Squibb in 2001, Mr. Mitchell had a fourteen-year career with GlaxoSmithKline, Inc., becoming Senior Vice President, Clinical Development and Product Strategy in 2000. Mr. Mitchell is also a director of Intrexon Corporation and of Ista Pharmaceuticals.

About ImmunoGen, Inc.

ImmunoGen, Inc. develops targeted anticancer therapeutics using the Company’s expertise in tumor biology, monoclonal antibodies, potent cancer-cell killing agents and engineered linkers. The Company’s Targeted Antibody Payload (TAP) technology uses monoclonal antibodies to deliver one of ImmunoGen’s proprietary cancer-cell killing agents specifically to tumor cells. There are now numerous TAP compounds in clinical development with a wealth of clinical data reported. ImmunoGen’s collaborative partners include Amgen, Bayer HealthCare Pharmaceuticals, Biotest, Lilly, Novartis, Roche, and Sanofi. The most advanced compound using ImmunoGen’s TAP technology, trastuzumab emtansine (T-DM1), is in Phase III testing through the Company’s collaboration with Genentech, a member of the Roche Group. More information about ImmunoGen can be found at www.immunogen.com.

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