ImmunoGen presents IMGN853 data against ovarian cancer, carcinomas at AACR meeting

ImmunoGen, Inc. (Nasdaq: IMGN), a biotechnology company that develops targeted anticancer products using its antibody expertise and Targeted Antibody Payload (TAP) technology, today announced the reporting of the first data on the Company's IMGN853 product candidate for the treatment of ovarian cancer and other types of solid tumors. The presentations are being given at the 102^nd Annual Meeting of the American Association for Cancer Research (AACR) in Orlando, FL.

IMGN853 is designed to selectively target and kill cancer cells expressing folate receptor 1 (FOLR1). This target is over-expressed on most cases of ovarian cancer as well as on other carcinomas including types of non-small cell lung cancers. IMGN853 was found to be highly effective against human ovarian cancer tumors in preclinical testing. The AACR's 2011 Program Committee recognized the abstract on the IMGN853 in vivo preclinical findings as scoring among the top 2% of abstracts for poster presentations.

IMGN853 is a TAP compound, which means it consists of a tumor-targeting antibody with one of ImmunoGen's highly potent cell-killing agents attached via an engineered linker. The antibody serves to target the TAP compound specifically to cancer cells, and the cell-killing agent serves to destroy these cells.

"We conduct ongoing research to continue to enhance our product development capabilities as well as our product pipeline, and IMGN853 reflects several technological innovations that we've made in recent years," commented John Lambert, Ph.D., Executive Vice President and Chief Scientific Officer. "For example, we engineered the linker used in IMGN853 to not only be stable like all of our linkers, but also to combat the multidrug resistance that makes certain types of cancers highly difficult to treat. This further increased the activity of IMGN853 in preclinical testing."

Dr. Lambert continued, "We also continually refine the criteria we use to generate and select antibodies for use in TAP compounds as we identify opportunities to further enhance each compound's therapeutic activity. We evaluated over 100 FOLR1-targeting antibodies in selecting the one used in IMGN853."

Among the findings being reported are data demonstrating:

• The target for IMGN853 - FOLR1 - is robustly expressed on most ovarian cancers as well as on certain non-small cell lung cancers and other carcinomas. This is based on target quantification methods developed by ImmunoGen scientists (abstract #3617);
• The design of IMGN853 has been optimized for its target - both in its antibody component and in the novel linker used to attach the highly potent payload to the antibody and control its release inside a cancer cell (abstract #4576); and
• The IMGN853 product candidate has been found to be highly active against human ovarian cancer tumors in preclinical testing (abstract #1760). This has been designated as a Highly Rated Poster Presentation by the 2011 Program Committee of the AACR.