News

WALTHAM, Mass.--(BUSINESS WIRE)--April 8, 2008--ImmunoGen, Inc. (Nasdaq: IMGN), a biopharmaceutical company that develops targeted anticancer therapeutics using its Tumor-Activated Prodrug (TAP) technology, today announced that the following will be reported at the Annual Meeting of the American Association for Cancer Research (AACR), to be held April 12-16, 2008 in San Diego, CA:

ImmunoGen's IMGN901 and IMGN242 Anticancer Compounds

"Efficacy of IMGN901 (huN901-DM1) in combination with bortezomib and lenalidomide against multiple myeloma cells in preclinical studies" (abstract #2146).

    --  Monday, April 14, 2008, 8:00 am - 12:00 noon PT, poster
        session 23, board number 21.
    --  IMGN901 plus bortezomib (Velcade(R)) demonstrated
        additive-to-synergistic activity in vivo, as did IMGN901 used
        in combination with lenalidomide (Revlimid(R)). IMGN901 is in
        clinical testing for the treatment of multiple myeloma and has
        shown objective evidence of activity as monotherapy. Future
        development pathways for this compound include its evaluation
        in combination with approved therapeutics and its continued
        development as monotherapy.

"Preclinical evaluation of IMGN901 (huN901-DM1) as a potential therapeutic for ovarian cancer" (abstract #2135).

    --  Monday, April 14, 2008, 8:00 am - 12:00 noon PT, poster
        session 23, board number 10.
    --  Found that IMGN901 offers potential utility in the treatment
        of ovarian cancer.

"Immunohistochemical analysis of the glycotope targeted by huC242-DM4 indicates strong expression in several tumor types with unmet medical need" (abstract #4898).

    --  Tuesday, April 15, 2008, 1:00 pm - 5:00 pm PT, poster session
        33, board number 3.
    --  Discusses tumor types that express the target for IMGN242.

Preclinical findings also are being reported on a clinical-stage TAP compound in development by an ImmunoGen collaborator (abstract #2133).

TAP Technology and Research

"Antibody-maytansinoid conjugates affect microtubule morphology and suppress microtubule dynamics in live cells" (abstract #1403).

-- Sunday, April 13, 2008, 1:00 pm - 5:00 pm PT, poster session

28, board number 4.

"Maytansine derivatives and metabolites of antibody-maytansinoid conjugates inhibit microtubule polymerization and strongly suppress microtubule dynamics" (abstract #1406).

-- Sunday, April 13, 2008, 1:00 pm - 5:00 pm PT, poster session

28, board number 7.

"Evaluation of the cytotoxic potencies of the major maytansinoid metabolites of antibody maytansinoid conjugates detected in vitro and in preclinical mouse models" (abstract #2150).

-- Monday, April 14, 2008, 8:00 am - 12:00 noon PT, poster

session 23, board number 25.

"Targeting regulatory T cells from cancer therapy: Understanding mechanism of antibody-mediated regulatory T cell depletion in vivo" (abstract #2072).

    --  Monday, April 14, 2008, 8:00 am - 12:00 noon PT, poster
        session 17, board number 7.

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 and IMGN242. Three TAP compounds are in clinical testing through ImmunoGen's collaborations with other companies - AVE9633 and SAR3419, in development by sanofi-aventis, and trastuzumab-DM1 (T-DM1), in development by Genentech. AVE1642, a naked antibody, also is in clinical testing through the Company's collaboration with sanofi-aventis. Multiple compounds are advancing towards the clinic through the ImmunoGen's collaborations and internal programs.

Velcade^® is a registered trademark of Millennium Pharmaceuticals, Inc. and Revlimid^® is a registered trademark of Celgene Corporation.

CONTACT:
Investors
ImmunoGen, Inc.
Carol Hausner, 781-895-0600
Executive Director, Investor Relations and Corporate Communications
info@immunogen.com

Media:
KMorrisPR
Kathryn Morris, 845-635-9828
Kathryn@kmorrispr.com