By Randall Osborne

West Coast Editor

To push its psoriasis product to market, Corixa Corp. is teaming with Medicis Pharmaceutical Corp. in a deal valued as high as $107 million in license fees, research funding and milestone payments.

"There are lots of immunotherapeutics being developed for psoriasis," said Steve Gillis, chairman and CEO of Seattle-based Corixa. "But they're mainly antibody-like molecules that inhibit antigen presentation or trafficking of cells believed to be involved in development of psoriatic lesions, and they're given pretty much continuously."

In ongoing Phase II trials, which Corixa hopes to complete by the end of this year, moderate to severe psoriatic patients will be given two PVAC shots three weeks apart, and will be monitored for 12 weeks after the second shot.

Corixa gets a non-refundable sum of $17 million up front, plus development milestone payments totaling up to $35 million, and more milestone payments of $55 million related to commercialization and sales.

Medicis, of Phoenix, also will buy inventory from Corixa, and pay royalties.

The injectable psoriasis treatment, called PVAC, is derived from Mycobacterium vaccae, and was developed by Corixa with New Zealand-based Genesis Research and Development Corp.

Having talked with the FDA about the Phase II trials' design, Corixa has increased the size of the study from 132 to 240 patients, in order for the trial potentially to qualify as an efficacy study on which the company could base an approval request.

A 52-week, Phase I/II open-label trial in the Philippines treated about 20 moderate to severe psoriatic patients, and more than half showed greater than a 75 percent decrease in disease severity. Their main side effect was redness and erythema at the injection site, and median duration of improvement for those responding was 51 weeks.

Pre-BLA Meeting Planned For Melacine

About 7 million people in the U.S. are afflicted with psoriasis, and about 30 percent are believed to have the moderate to severe form.

The company also reported the finish of a Phase III trial in 253 patients comparing its melanoma vaccine, Melacine, plus Intron A (alpha interferon) therapy in Stage IV metastatic melanoma patients to therapy with Intron A alone.

No survival advantage was noted, but women treated with both drugs survived significantly longer (353 days) than those treated with Intron A alone (187 days). Response rates in both arms were similar, but in women the two-drug regimen was much more successful, with a median duration of response of 668 days, compared to 157 days with Intron A only - possibly due to a more potent immune response against self-antigens in women.

"These trials have been going on for years, and they're the result of our acquisition of Ribi [ImmunoChem Research Inc.]," Gillis said. "They were started back in 1995, 1996." (See BioWorld Today, June 11, 1999, p. 1.)

Melacine consists of lysed, or broken, cells from two human melanoma cell lines combined with Corixa's proprietary Detox adjuvant. The company will meet with the FDA for a pre-biologics license application discussion in September.

Corixa's stock (NASDAQ:CRXA) closed Wednesday at $35.875, down $1.50.

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