ImmunoGen, Inc. Announces Clinical Data Presentations on Three TAP Compounds at Upcoming ASH Annual Meeting and Exposition

ImmunoGen, Inc. (Nasdaq: IMGN), a biopharmaceutical company that develops targeted anticancer therapeutics, announced today that presentations of clinical data for three product candidates employing its Targeted Antibody Payload (TAP) technology will be made at the 51 ^st American Society of Hematology (ASH) Annual Meeting and Exposition to be held in New Orleans, LA, on December 5-8, 2009.

Updated clinical findings will be reported on ImmunoGen’s IMGN901 TAP compound when used for the treatment of multiple myeloma. Additionally, the first clinical data will be reported for SAR3419 in the treatment of non-Hodgkin’s lymphoma and BT-062 in the treatment of multiple myeloma. These compounds are in development through the Company’s collaborations with sanofi-aventis and Biotest, respectively.

“Having clinical data presentations on multiple product candidates at ASH is reflective of the breadth of TAP compounds now advancing in the clinic,” commented Daniel Junius, President and CEO. “While TAP product candidates targeting solid tumors are attracting considerable attention, meaningful progress also is being made with therapies for the treatment of liquid tumors.”

Oral Presentation

Abstract: 585
Title: Phase I Multi-Dose Escalation Study of the Anti-CD19 Maytansinoid Immunoconjugate SAR3419 Administered by Intravenous (IV) Infusion Every 3 Weeks to Patients with Relapsed/ Refractory B-Cell Non-Hodgkin’s Lymphoma (NHL)
When: Monday, December 7, 2009 at 3:15 pm (CT)
Where: R02-R05

Poster Presentations

Abstract: 1862
Title: Phase I Study of BT062 Given as Repeated Single Dose Once Every 3 Weeks in Patients with Relapsed or Relapsed/Refractory Multiple Myeloma
When: Saturday, December 5, 2009 from 5:30 - 7:30 pm (CT)
Where: Hall E, Poster Board I-884

Abstract: 2883
Title: Phase I Study of IMGN901, Used as Monotherapy, in Patients with Heavily Pre-Treated CD56-Positive Multiple Myeloma - A Preliminary Safety and Efficacy Analysis
When: Sunday, December 6, 2009 from 6:00 - 8:00 pm (CT)
Where: Hall E, Poster Board II-859

About ImmunoGen, Inc.

ImmunoGen, Inc. develops targeted anticancer therapeutics using its expertise in cancer biology, monoclonal antibodies and the creation and attachment of potent cancer-cell killing agents. The Company’s TAP technology uses antibodies to deliver one of ImmunoGen’s proprietary cancer-cell killing agents specifically to tumors. In addition to the Company’s product pipeline, compounds utilizing the TAP technology are in clinical testing through ImmunoGen’s collaborations with Genentech (a wholly-owned member of the Roche Group), sanofi-aventis, Biogen Idec and Biotest. The most advanced compound, trastuzumab-DM1 (T-DM1), is in Phase III testing being conducted by Genentech and Roche. Other ImmunoGen collaborative partners include Bayer HealthCare and Amgen. More information about ImmunoGen can be found at www.immunogen.com.

This press release includes forward-looking statements. For these statements, ImmunoGen claims the protection of the safe harbor for forward-looking statements provided by the Private Securities Litigation Reform Act of 1995. It should be noted that there are risks and uncertainties related to the development of novel anticancer products, including IMGN901, SAR3419, and BT-062, including risks related to uncertainties around clinical trials conducted and their timings and results. A review of these risks can be found in ImmunoGen’s Annual Report on Form 10-K for the fiscal year ended June 30, 2009 and other reports filed with the Securities and Exchange Commission.