West Coast Editor

ImmunoGen Inc.'s deal with Centocor Inc. to develop and sell preclinical IMGN388 for cancer brings to four the number of Tumor-Activated Prodrug (TAP) compounds that have become the subjects of collaborations.

The deal with Horsham, Pa.-based Centocor brings no up-front money for rights to the drug (previously known as CNTO365). Instead, the Johnson & Johnson subsidiary has agreed instead to an arrangement that allows for later opt-in, ahead of a pivotal study.

Michael Parks, vice president of corporate communications for Centocor, called the deal structure a way for Centocor to balance risk with investment, and said such setups are becoming more common in the industry (despite big pharma's pipeline starvation). "We'll make a decision down the road, after they show successful proof of concept," Parks told BioWorld Today.

If Centocor takes the option, the two firms will split development costs and profits, with ImmunoGen getting royalties. If Centocor backs away from the option, ImmunoGen could shop for a new partner, and stands to get milestone payments as high as $30 million from ImmunoGen, plus royalties. The first milestone payment would be due when a successful Phase III trial finishes.

TAP compounds consist of a monoclonal antibody that binds specifically to a target - its antigen - on cancer cells, with a cell-killing agent attached. IMGN388 is a fully human, anti-av integrin antibody that came from Princeton, N.J.-based Medarex Inc.'s platform (Centocor is developing it separately as a naked antibody), paired with ImmunoGen's DM4 maytansinoid conjugate. The target is found on tumor cells as well as endothelial cells.

"That's one of the things we found interesting about [the target]," said Carol Hausner, director of investor relations and corporate communications for Cambridge, Mass.-based ImmunoGen. "It's expressed on certain tumor types, such as melanoma, colorectal and breast, but also on newly forming vessels," which could mean the drug has an anti-angiogenic effect. Centocor reported encouraging preclinical data in mouse tumor models last June in Clinical Cancer Research.

ImmunoGen is pleased enough with the terms. "We were able to pick up a nice compound and take it into the clinic and see what it shows," Hausner said. Filing of an investigational new drug application is expected in the second quarter of this year.

"We expect up to three TAP compounds to enter the clinic by the end of our June 30 fiscal year, and [IMGN388] is counted as one of them," she said.

ImmunoGen's other deals for TAP compounds include the approved breast-cancer therapy Herceptin (trastuzumab), from South San Francisco-based Genentech Inc., which is focused on trastuzumab-DM1, or T-DM1. With the Sanofi Aventis Group, of Paris, ImmunoGen has agreements for AVE9633 and SAR3419. Also part of the Sanofi relationship is the naked antibody AVE1642.

A pair of TAP compounds wholly owned by ImmunoGen also are undergoing clinical tests: IMGN901 (huN901-DM1) and IMGN242 (huC242-DM4).

ImmunoGen had $53.6 million in cash and marketable securities at the end of September, and Dan Junius, the company's chief financial officer, said over the summer that the firm wants to keep at least a year's worth of cash on hand.

Brian Rye, analyst with Janney Montgomery Scott LLC, expects the firm to return to the equity markets before the fiscal year's end.

Rye holds a "buy" rating on the stock (NASDAQ:IMGN), which closed Thursday at $3.79, down 39 cents.