Washington Editor

Genentech Inc. and partner XOMA Ltd. won FDA approval for Raptiva, a biologic for psoriasis that can be self-administered once weekly on a continuous basis.

Specifically, the FDA approved Raptiva (efalizumab, formerly Xanelim) for the treatment of chronic moderate to severe plaque psoriasis in adults ages 18 or older who are candidates for systemic therapy or phototherapy.

Raptiva is a subcutaneous injection expected to carry an average wholesale price of $17,800 per year per patient. Tara Cooper, spokeswoman for Genentech, of South San Francisco, told BioWorld Today. The company expects Raptiva to be on the shelves by Thanksgiving.

For XOMA, a Berkeley, Calif.-based company, approval of Raptiva is particularly exciting. First of all, Raptiva is the 20-year-old company's first FDA approval, and the company can anticipate a revenue stream. Not to mention that the biologic may dramatically change the way psoriasis patients control their disease, Patrick Scannon, XOMA's chief scientific and medical officer, told BioWorld Today.

Psoriasis treatments currently available, including Amevive made by Cambridge, Mass.-based Biogen Inc., and phototherapy or light therapy are saddled with certain disadvantages not characteristic of Raptiva, Scannon said.

Amevive is used on and off in 12-week cycles. While many patients will remain in remission during the off periods, some might experience a recurrence of the disease, Scannon said. Meanwhile, phototherapy and light therapy are life disrupting in the sense that patients have to receive therapy two to three days a week, he said.

"The ability to self administer Raptiva in your home once a week on a continuous basis is really a big deal," said Scannon, a founder of XOMA. "Raptiva will keep the disease suppressed."

Raptiva also has a good safety profile. In clinical trials, less than 1 percent of patients were discontinued from treatment due to acute adverse events. The most common adverse events were headache, infection (mostly upper respiratory), chills, nausea, pain, myalgia, flu syndrome, fever, back pain and acne, Genentech said.

Raptiva is a humanized monoclonal antibody and targeted T-cell modulator designed to inhibit the inflammatory cascade in psoriasis. Specifically, it works by blocking the binding of LFA-1 to ICAM-1, inhibiting the T cells from binding to key cells in the psoriasis cascade, rather than depleting T cells.

Genentech's Cooper said Raptiva has been shown to have a rapid onset of action, meaning patients could begin seeing activity at four weeks.

While Genentech discovered Raptiva, XOMA was invited into the game about seven years ago, Peter Davis, XOMA's chief financial officer, told BioWorld Today.

XOMA has preclinical capabilities, process development-scale manufacturing and the ability to run clinical trials, so "Genentech came to us, because for a variety of reasons they were resource constrained in terms of being able to move Raptiva forward," Davis said. "We have the capabilities, and this has been a success. This is an important part of our business strategy, which is to try to take advantage of our development capabilities and trade that for gaining interest in promising products in other companies' pipelines - then we can help them move forward."

XOMA will receive 25 percent of U.S. sales, and on sales outside the U.S., XOMA will receive a mid-single-digit royalty, Davis said. Serono SA, of Geneva, has rights outside the U.S., except in Japan, where Genentech has rights. Serono filed for European regulatory approval in late February. (See BioWorld Today, Feb. 7, 2003.)

When the partners enter the market, they should face competition from others, including Amevive and Enbrel, a product owned by Amgen Inc., of Thousand Oaks, Calif.

Indeed, Mark Schoenebaum, senior biotechnology analyst with U.S. Bancorp Piper Jaffray, told BioWorld Today the peak worldwide market for biologics in psoriasis is about $1 billion to $2 billion for all products combined. He said Raptiva has a good shot at capturing $400 million to $500 million worldwide.

Raptiva's approval was based on data from four randomized, placebo-controlled Phase III trials. The studies were designed to evaluate the safety and efficacy of Raptiva in treating chronic moderate to severe plaque psoriasis.

The studies had a primary efficacy endpoint of 75 percent improvement in the Psoriasis Area and Severity Index (PASI). Secondary endpoints included physician assessment and patient-reported outcomes.

According to Genentech, Raptiva demonstrated efficacy and maintained response in most patients after 12 weeks of treatment. Sustained responses to Raptiva also have been observed in uncontrolled, open-label extension treatment trials when patients received Raptiva without interruption for 24 weeks.

The FDA's Dermatologic and Ophthalmic Drugs Advisory Committee in September voted unanimously in favor of Raptiva for use in the approved indication. (See BioWorld Today, Sept. 10, 2003.)

Scannon said the companies have met to develop a list of other possible priorities and indications for Raptiva, but have yet to announce their intentions.

Genentech's stock (NYSE:DNA) rose $1.91 Tuesday to close at $81.80. XOMA's stock (NASDAQ:XOMA) fell 15 cents to close at $7.70.