ImmunoGen, Inc. Announces Presentations on Clinical-Stage Compounds at ASH Annual Meeting

ImmunoGen, Inc. (Nasdaq: IMGN), a biopharmaceutical company that develops targeted anticancer therapeutics using its Tumor-Activated Prodrug (TAP) technology, today announced that findings with four compounds now in clinical testing will be reported at the American Society of Hematology (ASH) annual meeting to be held in Atlanta, GA, December 8-11, 2007. "The breadth of the findings that will be reported at ASH this year reflects the tremendous progress by us and our collaborators,” commented Mitchel Sayare, Chairman and CEO. "There are now six compounds in the clinic through our own programs and those of our collaborators, and we expect up to three more TAP compounds to enter the clinic by the end of our fiscal year in June 2008. We are pleased with the growing body of meaningful clinical findings being reported.” Posters on the following clinical-stage compounds will be presented at the ASH annual meeting. IMGN901 (HuN901-DM1) "Phase I Study of huN901-DM1 (BB-10901) in Patients with Relapsed and Relapsed/Refractory CD56-Positive Multiple Myeloma.” (abstract # 1174) Poster Session Saturday, December 8, 5:30 – 7:30 pm. IMGN901, a TAP compound, is wholly owned by ImmunoGen. AVE1642 "Phase I Study of AVE1642 Anti-IGF-1R Monoclonal Antibody in Patients with Advanced Multiple Myeloma.” (abstract #1166) Poster Session Saturday, December 8, 5:30 – 7:30 pm. AVE1642, a naked (non-conjugated) antibody, was initially developed by ImmunoGen and was licensed to sanofi-aventis as part of a broader collaboration between the companies. AVE9633 "An Open Label, Dose Escalation Study of AVE9633 Administered as a Single Agent by Intravenous (IV) Infusion Weekly for 2 Weeks in a 4-Week Cycle to Patients with Relapsed or Refractory CD33-Positive Acute Myeloid Leukemia (AML).” (abstract #1850) Poster Session Sunday, December 9, 6:00 – 8:00 pm. This TAP compound also was initially developed by ImmunoGen and licensed to sanofi-aventis as part of a broader collaboration between the companies. SAR3419 "Superior Anti-Tumor Activity of the CD19-Directed Immunotoxin, SAR3419, to Rituximab in Non-Hodgkin’s Xenograft Animal Models: Preclinical Evaluation.” (abstract #2339) Poster Session Sunday, December 9, 6:00 – 8:00 pm. Sanofi-aventis advanced this TAP compound into clinical testing for the treatment of non-Hodgkin’s lymphoma and other B-cell malignancies in October 2007. It also was initially developed by ImmunoGen. In addition to the findings being reported on these clinical-stage compounds, other ImmunoGen collaborators are presenting data on programs using the Company's TAP 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. 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 development through the Company’s collaboration with sanofi-aventis. Multiple compounds are in research/preclinical development through the ImmunoGen’s collaborations and internal programs. This press release includes forward-looking statements based on management’s current expectations. The statements include, but are not limited to, the statement that ImmunoGen expects up to three more TAP compounds to enter the clinic by the end of the Company’s fiscal year in June 2008. 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 ImmunoGen’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 difficulties inherent in the development of novel pharmaceuticals, including uncertainties as to the timing, expense and results of preclinical studies and regulatory preparations and other factors more fully described 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.