News

CAMBRIDGE, Mass.--(BUSINESS WIRE)--May 24, 2007--ImmunoGen, Inc. (Nasdaq: IMGN), a biopharmaceutical company that develops targeted anticancer therapeutics using its Tumor-Activated Prodrug (TAP) technology, today announced that clinical findings for three different TAP compounds for the treatment of solid tumors are to be reported at the 43rd American Society of Clinical Oncology (ASCO) Annual Meeting to take place June 1-5, 2007 in Chicago, IL.

Trastuzumab-DM1 (abstract #1042)

"A phase I study of trastuzumab-MCC-DM1 (T-DM1), a first-in-class HER2 antibody-drug conjugate (ADC), in patients (pts) with HER2+ metastatic breast cancer (BC)."

• Saturday, June 2, 2:00-6:00 pm: Breast Cancer - Metastatic General Poster Session (poster #G4).
• Trastuzumab-DM1 is in development by Genentech.

HuC242-DM4 (abstract #3062)

"A phase I study of a CanAg-targeted immunoconjugate, huC242-DM4, in patients with Can Ag-expressing solid tumors."

• Sunday, June 3, 8:00 am-12:00 noon: Developmental Therapeutics: Immunotherapy General Poster Session (poster #F14).
• HuC242-DM4 is wholly owned by ImmunoGen.

HuN901-DM1 (abstract #18084)

"Phase II trial of huN901-DM1 in patients with relapsed small cell lung cancer (SCLC) and CD56-positive small cell carcinoma."

• To be published as abstract in the Journal of Clinical Oncology.
• HuN901-DM1 is wholly owned by ImmunoGen.

About ImmunoGen's TAP Technology

ImmunoGen created its TAP technology to enhance the anticancer activity of tumor-targeting antibodies while maintaining a favorable tolerability profile. The Company attaches to an antibody one of ImmunoGen's proprietary cell-killing agents. 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, and also outlicenses its technology for use by other companies with their proprietary antibodies. Companies licensing the right to develop anticancer compounds to specific targets using ImmunoGen's TAP technology include Biogen Idec, Biotest AG, Centocor (Johnson & Johnson), Genentech, and sanofi-aventis.

Four TAP compounds are already in clinical testing - huN901-DM1 and huC242-DM4, in development by ImmunoGen, trastuzumab-DM1, in development by Genentech, and AVE9633, in development by sanofi-aventis. ImmunoGen expects its collaborators to advance two additional TAP compounds into clinical testing in 2007.

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 - huN901-DM1 and huC242-DM4. Three anticancer compounds are in clinical testing through ImmunoGen's collaborations with other companies - AVE9633 and AVE1642, in development by sanofi-aventis, and trastuzumab-DM1, in development by Genentech. Multiple compounds are in research/preclinical development.

This press release includes forward-looking statements based on management's current expectations. 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. Various factors could cause the Company's actual results to differ materially from those discussed or implied in the forward-looking statements and you are cautioned not to place undue reliance on these forward-looking statements, which are current only as of the date of this release. Factors that could cause future results to differ materially from such expectations include, but are not limited to: the outcome of the Company's research and clinical development processes; the outcome of the Company's collaboration partners' research and clinical development processes; the difficulties inherent in the development of novel pharmaceuticals, including uncertainties as to the timing, expense and results of preclinical studies and clinical trials; the Company's dependence on collaborative partners; and other factors more fully described in ImmunoGen's Annual Report on Form 10-K for the fiscal year ended June 30, 2006 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

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