News

CAMBRIDGE, Mass., Apr 01, 2006 (BUSINESS WIRE) -- ImmunoGen, Inc. (Nasdaq: IMGN), a biopharmaceutical company that develops targeted anticancer therapeutics, today announced that extensive data on the Company's antibody-maytansinoid, or Tumor-Activated Prodrug (TAP), technology will be reported at the American Association for Cancer Research (AACR) meeting being held in Washington, DC, April 1-5, 2006. In addition, preclinical findings will be reported for several compounds in development by ImmunoGen and by the Company's collaborator, the sanofi-aventis Group.

"In the past few years, we've significantly increased our ability to tailor the design of antibody-maytansinoid compounds for different antibodies and targets to maximize the therapeutic window achieved, which is reflected in TAP compounds now in clinical testing," commented Walter Blattler, PhD, Executive Vice President, Science and Technology. "The findings to be presented demonstrate the careful assessment of alternative product designs that is conducted by ImmunoGen and our collaborators in the development of each TAP compound. They also illustrate the research we're doing to enable the successful application of our technology to every type of cancer."

Data on ImmunoGen's technology to be reported at AACR include:

-- Findings that further confirm that a TAP compound is stable while circulating in the bloodstream (abstract #1181);

-- Results that demonstrate that, upon entering a cancer cell, a TAP compound is rapidly activated - causing cell-cycle arrest - and this activation involves lysosomal processing (abstract #1175);

-- Findings that show that alternative TAP compound designs result in different active agents being formed inside a cancer cell (abstract #1994);

-- Data that demonstrate that alternative TAP compound designs lead to important differences in anti-tumor activity (abstract #3727). For example, the design of a TAP compound has been found to impact its activity against tumors with heterogeneous expression of the target antigen - tumors that contain cancer cells that are expressing the target antigen and also cancer cells that are not.

Additionally, preclinical data will be reported on a number of compounds in development by ImmunoGen or that were originally developed by ImmunoGen and now are part of the Company's collaboration with the sanofi-aventis Group. These include:

-- Findings from ImmunoGen's evaluation of alternative design options for its huC242-DM1 compound that demonstrate that the huC242-DM4 design provides the best activity across relevant tumor types (abstract #3727);

-- Data on the activity of the TAP compound AVE9633, now in clinical development by the sanofi-aventis Group, against human acute myeloid leukemia cells isolated from patients (abstract #5558);

-- Findings from preclinical studies with the anti-IGF-1R compound AVE1642, which is in development by the sanofi-aventis Group (abstracts #1222 and 1225); and

-- Results from preclinical studies evaluating the CD19-targeting TAP compound SAR3419, which is in development by the sanofi-aventis Group (abstract #3731).

All of these abstracts can be viewed on the AACR website, www.aacr.org.

A TAP compound consists of an antibody that binds to a target found on tumor cells with a potent cell-killing agent attached. The antibody serves to target the compound specifically to cancer cells and the cytotoxic agent serves to kill those cells. ImmunoGen has created potent derivatives of the cell-killing agent maytansine, including DM1 and DM4, expressly for antibody-directed delivery to cancer cells, and also developed alternative means of attaching these agents to antibodies. The significance of ImmunoGen's design alternatives recently has gained increased visibility as more companies are developing anticancer compounds using ImmunoGen's technology.

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. Three TAP compounds are in clinical testing - huN901-DM1 and huC242-DM4, which are wholly owned by ImmunoGen, and AVE9633, which is in development by the sanofi-aventis Group. A fourth TAP compound, trastuzumab-DM1 in development by Genentech, now has an effective IND. Genentech, Centocor (a wholly-owned subsidiary of Johnson & Johnson), Biogen Idec, the sanofi-aventis Group, Millennium Pharmaceuticals, Inc., Boehringer Ingelheim, and Abgenix have licensed the right to develop and/or test TAP compounds to specific targets; ImmunoGen also has a broader collaboration with the sanofi-aventis Group.

his 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 ImmunoGen's development of our own products, as well as to the development of products by our collaborators, including the sanofi-aventis Group. A review of these risks can be found in ImmunoGen's Annual Report on Form 10-K for the fiscal year ended June 30, 2005 and other reports filed with the Securities and Exchange Commission.

SOURCE: ImmunoGen, Inc.

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