ImmunoGen, Inc. Initiates Clinical Testing of HuN901-DM1

ImmunoGen, Inc. (Nasdaq: IMGN) today announced the initiation of clinical testing with its Tumor-Activated Prodrug (TAP) compound, huN901-DM1, for the treatment of multiple myeloma. This study expands the huN901-DM1 clinical program - the compound also is in two clinical trials for the treatment of small-cell lung cancer.

The huN901-DM1 multiple myeloma study is being conducted at the Jerome Lipper Center for Multiple Myeloma of the Dana-Farber Cancer Institute in Boston, MA. Robert Schlossman, MD, is the Principal Investigator. Co-investigators in the study include Kenneth Anderson, MD, Paul Richardson, MD, and Nikhil Munshi, MD, of the Jerome Lipper Center. Additional clinical centers are expected to be added.

The primary objective of this Phase I study is to evaluate the safety of huN901-DM1 in patients with relapsed or refractory multiple myeloma, and to identify the maximum tolerated dose of the compound in this patient population. The study also will evaluate the anticancer activity of huN901-DM1 in multiple myeloma.

The first dose level to be evaluated in this study will be close to the maximum tolerated dose that was established with the compound as part of the small-cell lung cancer clinical program. Patients will receive huN901-DM1 - as monotherapy - once weekly for two consecutive weeks every three weeks.

Patients need to have multiple myeloma that expresses the CD56 antigen targeted by huN901-DM1. Previous research conducted at the Dana-Farber Cancer Institute confirms that most cases of multiple myeloma express CD56.

In the same preclinical research, conducted in the laboratory of Dr. Munshi, huN901-DM1 was found to selectively target and kill CD56-expressing multiple myeloma cells. The compound was found to have substantial activity even when the multiple myeloma cells were in the presence of bone marrow stromal cells (BMSCs). There is evidence that multiple myeloma cells adhering to BMSCs are able to resist being killed by standard chemotherapeutic agents.

Dr. Schlossman commented, "HuN901-DM1 is a targeted approach to the treatment of multiple myeloma, in contrast to the currently approved agents for this malignancy. The findings from the preclinical multiple myeloma studies are encouraging, and we look forward to assessing this compound clinically."

HuN901-DM1 is in development by ImmunoGen for the treatment of cancers that express the CD56 protein targeted by the compound. CD56-expressing malignancies include multiple myeloma, small-cell lung cancer, and other cancers of neuroendocrine origin. HuN901-DM1 comprises the anti-CD56 antibody, huN901, and the potent cell-killing agent, DM1. The huN901 antibody is used to target the compound specifically to CD56-expressing cancer cells and the DM1 serves to kill these cells.