ImmunoGen, Inc. Announces Initiation of Randomized Clinical Trial Evaluating IMGN901 for First-Line Treatment of Small-Cell L...

ImmunoGen, Inc. (Nasdaq: IMGN), a biotechnology company that develops antibody-based anticancer products using its Targeted Antibody Payload (TAP) technology, today announced the initiation of a randomized Phase I/II clinical trial to evaluate its proprietary product candidate, IMGN901 (lorvotuzumab mertansine), for first-line treatment of small-cell lung cancer (SCLC) in patients with extensive disease.

“We believe IMGN901 has the potential to be an important treatment for SCLC, particularly as part of a combination regimen,” commented James O’Leary, MD, Vice President and Chief Medical Officer. “IMGN901 has been found to be well tolerated and to demonstrate evidence of activity when used as a single agent to treat this highly aggressive cancer. The tolerability profile of IMGN901 supports evaluating it in combination with other active agents, and – in preclinical testing – it has shown highly compelling activity used together with these same therapies.”

This multi-national trial will evaluate IMGN901 used together with carboplatin plus etoposide (C/E) – standard care for first-line treatment of SCLC – versus C/E alone. In the dose-escalation Phase I portion of the trial, increasing doses of IMGN901 will be administered with C/E to establish the maximum tolerated dose of the study compound with C/E. In the Phase II portion, patients will be randomized to receive C/E plus IMGN901 (60 patients) or C/E alone (30 patients).

IMGN901 will be administered weekly for two weeks in a three-week cycle, and C/E will be dosed on the standard three-week schedule. Patients can receive up to six cycles of C/E, consistent with established usage, but those randomized to also receive IMGN901 will be allowed to remain on the study drug alone as long as they continue to benefit from it.

The primary endpoint of this trial is progression-free survival (PFS). Secondary endpoints include PFS at 6 months, overall survival at 12 months, time to progression, overall survival, and overall response rate.

About IMGN901

IMGN901 consists of ImmunoGen’s CD56-targeting antibody with the Company’s proprietary cancer-cell killing agent, DM1, attached using one of ImmunoGen’s engineered linkers. This TAP compound is wholly owned by ImmunoGen and is in clinical testing for the treatment of several CD56+ malignancies – SCLC, Merkel cell carcinoma, ovarian cancer and multiple myeloma. IMGN901 has been granted orphan drug designation for SCLC and for MCC in the US and in Europe.

About Small-Cell Lung Cancer (SCLC)

It is expected that approximately 31,000 new cases of SCLC will be diagnosed in the US this year.1 SCLC tends to spread more rapidly than non-small cell lung cancer and has usually spread by the time of diagnosis. As a result, SCLC is usually treated with chemotherapy rather than with surgery. Once patients relapse after first-line chemotherapy, survival is usually less than 6 months.2

About ImmunoGen, Inc.

ImmunoGen, Inc. develops targeted anticancer therapeutics using the Company's expertise in tumor biology, monoclonal antibodies and potent cancer-cell killing agents. The Company's TAP technology uses monoclonal antibodies to deliver one of ImmunoGen's proprietary cancer-cell killing agents specifically to tumor cells. There are currently seven TAP compounds in the clinic, with a wealth of clinical data reported with the technology. ImmunoGen’s collaborative partners include Amgen, Bayer Schering Pharma, Biogen Idec, Biotest, Genentech (a member of the Roche Group), Novartis, and sanofi-aventis. The most advanced compound using ImmunoGen's TAP technology, trastuzumab-DM1 (T-DM1), is in Phase III testing through the Company's collaboration with Genentech. More information about ImmunoGen can be found at www.immunogen.com.

1 ACS Cancer Facts & Figures, 2010.2 Davies, A., 2004.

This 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 the development of novel anticancer products, including IMGN901, including risks related to uncertainties around clinical trials conducted and their timings and results. A review of these risks can be found in ImmunoGen’s Annual Report on Form 10-K for the fiscal year ended June 30, 2010 and other reports filed with the Securities and Exchange Commission.