News

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Feb. 1, 2008--ImmunoGen, Inc. (Nasdaq: IMGN), a biopharmaceuticals company that develops targeted anticancer therapeutics using its Tumor-Activated Prodrug (TAP) technology, today announced that Biogen Idec Inc. (Nasdaq: BIIB) has submitted an Investigational New Drug (IND) application for BIIB015. This event triggers a $1.5 million milestone payment to ImmunoGen. BIIB015 comprises ImmunoGen's cell-killing agent, DM4, linked to Biogen Idec's Cripto-targeting antibody, and is in development by Biogen Idec for the treatment of solid tumors that express the Cripto antigen.

"BIIB015 is a promising new treatment for solid tumors and we are delighted with the progress being made by Biogen Idec," stated Mitchel Sayare, Chairman and CEO. "We outlicense our TAP technology to other companies for use with their proprietary antibodies both for the financial return and to expand the number of compounds in development. We expect there to be as many as eight TAP compounds in the clinic by this summer - the five already in human clinical testing plus three more compounds advancing toward the clinic."

In 2004, Biogen Idec licensed the exclusive right to use ImmunoGen's maytansinoid TAP technology with antibodies that target Cripto. This agreement entitles ImmunoGen to receive milestone payments upon achievement of the events defined in that agreement, and also to receive royalties on the sales of any products that use ImmunoGen's maytansinoid TAP technology. Biogen Idec is responsible for product development, manufacturing, and commercialization.

About ImmunoGen's TAP Technology

ImmunoGen created its TAP technology to enhance the anticancer activity of tumor-targeting monoclonal antibodies while maintaining a favorable tolerability profile. ImmunoGen attaches to an antibody one of the Company's proprietary cell-killing agents (DM1, DM4). The antibody serves to deliver the agent specifically to cancer cells and the agent serves to kill the cancer cells. The agent is attached using one of the Company's "linkers." ImmunoGen has developed alternative cell-killing agents and linkers so the best product design can be achieved for each antibody and its target.

ImmunoGen uses its cell-killing agents with its wholly-owned antibodies to create its own anticancer compounds. ImmunoGen also outlicenses its technology for use by other companies with their proprietary antibodies.

About ImmunoGen, Inc.

ImmunoGen, Inc. develops targeted anticancer biopharmaceuticals. The Company's proprietary TAP technology uses tumor-targeting antibodies to deliver a potent cell-killing agent specifically to cancer cells. Two TAP compounds wholly owned by ImmunoGen are in clinical testing - IMGN901 (huN901-DM1) and IMGN242 (huC242-DM4). Three TAP compounds are in clinical testing through ImmunoGen's collaborations with other companies - AVE9633 and SAR3419, in development by sanofi-aventis, and T-DM1 (trastuzumab-DM1), in development by Genentech. Additionally, the naked antibody compound, AVE1642, is in clinical testing through the Company's collaboration with sanofi-aventis. Multiple compounds are in research/preclinical development through ImmunoGen's collaborations and internal programs.

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 Company's development of its own products, as well as to the development of products, including BIIB015, by our collaborators. A review of these risks can be found in ImmunoGen's Annual Report on Form 10-K for the fiscal year ended June 30, 2007 and other reports filed with the Securities and Exchange Commission.

    CONTACT: Investors:
             ImmunoGen, Inc.
             Carol Hausner, 617-995-2500
             Executive Director, Investor Relations
             and Corporate Communications
             info@immunogen.com
             or
             Media:
             For ImmunoGen, Inc.
             KMorrisPR
             Kathryn Morris, 845-635-9828
             Kathryn@kmorrispr.com
    SOURCE: ImmunoGen, Inc.