ImmunoGen, Inc. Earns Milestone With Start of SAR3419 Phase II Testing

WALTHAM, Mass., Oct. 20, 2011 (GLOBE NEWSWIRE) -- ImmunoGen, Inc. (Nasdaq:IMGN), a biotechnology company that develops targeted anticancer products using its antibody expertise and Targeted Antibody Payload (TAP) technology, today announced that SAR3419 has started Phase II testing. This event triggers a $3 million milestone payment to ImmunoGen. SAR3419 was created by ImmunoGen and licensed to Sanofi preclinically as part of a broader collaboration between the companies.

SAR3419 is a potential new treatment for CD19+ non-Hodgkin's lymphoma (NHL) and other B-cell malignancies. In Phase I testing, this TAP compound demonstrated activity across an array of NHL histological subtypes in patients with recurrent disease.^1,2 It also demonstrated activity in patients with both rituximab (Rituximab®)-refractory and -responsive disease. SAR3419 was found to be generally well tolerated with a notable lack of significant myelosuppression.

Sanofi's Phase II testing will focus on evaluating SAR3419 as a treatment for diffuse large B-cell lymphoma (DLBCL) and for B-cell acute lymphoblastic lymphoma (B-ALL). Today there are limited treatment options for B-ALL and also for DLBCL that has failed to respond to front-line therapy or recurred after treatment. DLBCL is the most common type of NHL, accounting for approximately one-third of all cases, while B-ALL accounts for a similar percentage of acute leukemia cases.^3,4

"Not only is the number of TAP compounds in the clinic expanding markedly, but more TAP compounds are progressing deeper into clinical testing," commented Daniel Junius, President and CEO. "Trastuzumab emtansine, or T-DM1, is in multiple Phase III trials, SAR3419 is now in Phase II, and both our IMGN901 compound and Biotest's BT-062 are expected to begin Phase II testing during our current fiscal year. Additionally, Bayer HealthCare's BAY 94-9343 recently began Phase I testing, bringing the total number of TAP compounds in the clinic to seven. Of particular importance, we've advanced another of our wholly owned compounds, IMGN529, to having an active IND and are moving forward with starting its Phase I evaluation."

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 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 and a wealth of clinical data reported. ImmunoGen's collaborative partners include Amgen, Bayer HealthCare Pharmaceuticals, Biotest, 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.

¹Younes, A. et al., ASH, Dec. 2009

²Coiffer B. et al., 11^th International Conference on Malignant Lymphoma, June 2011

³Knowcancer.com, Diffuse (Intravascular) large B-cell lymphoma

⁴Clinical Flow Wiki, Acute B Lymphoblastic Leukemia (B-ALL)

Rituxan® is a registered trademark of Biogen Idec.

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 by ImmunoGen and the Company's collaborators, including risks related to clinical studies, 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, 2011 and other reports filed with the Securities and Exchange Commission.

CONTACT:  For Investors:

          Carol Hausner 

          Executive Director, Investor Relations and 

           Corporate Communications

          ImmunoGen, Inc.

          (781) 895-0600

          info@immunogen.com



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