Genentech Drug for Psoriasis Gets Approval of FDA

Genentech Inc.’s Raptiva received Food and Drug Administration approval Monday, raising the stakes in the market for biotech psoriasis drugs.

Raptiva, a once-weekly shot, becomes the second biotechnology drug for psoriasis -- a category that some analysts believe could top $1 billion a year by 2006. Biogen Inc.’s intravenous medication Amevive reached the market this year.

Genentech’s chief rival is likely to be Amgen Inc. of Thousand Oaks. Enbrel, Amgen’s rheumatoid arthritis drug, has not yet been approved for psoriasis, but analysts estimate that 10% to 15% of Enbrel’s new prescriptions are being used for treatment of psoriasis.

Raptiva will cost $14,000 a year, Genentech said, about the same as Enbrel. Genentech developed the drug with Xoma Ltd., a Berkeley biotechnology company, and will share profits with it.

Genentech, based in South San Francisco, has seen its stock more than double since May when it announced that its experimental colon cancer drug Avastin added five months to the lives of patients in a large clinical trial. Analysts said Avastin could have $1 billion in sales and reach the market early next year.

Genentech’s announcement about Raptiva came Monday after the market close. The company’s shares closed up 2 cents at $79.82 on the New York Stock Exchange.

Genentech is targeting 500,000 patients with moderate to severe psoriasis, a skin condition that causes an itchy, crusty rash. About 4 million people in the United States have psoriasis, most with mild symptoms such as lightly flaking skin.

Analysts believe Genentech could rack up Raptiva sales of $10 million this year and about $60 million in 2004.

Biogen’s Amevive is expected to have sales of $50 million this year. Amgen’s Enbrel sales are expected to surpass $1 billion, though most of that is in the rheumatoid arthritis category; Amgen expects to receive FDA approval for the drug as a psoriasis treatment early next year.

Diane Parks, Genentech’s vice president for specialty pharmaceuticals, said the market was big enough for all three biotech drugs.

“It isn’t about Raptiva winning and Enbrel losing,� she said.

The biotech drugs offer alternatives to conventional treatments for psoriasis, some of which have severe side effects. A chemotherapy drug commonly used for psoriasis can cause liver damage; prolonged ultraviolet light therapy, another routine treatment, can lead to skin cancer.

The new biotech drugs are significantly more expensive than traditional therapies, which cost a few thousand dollars a year.

There are signs that the biotech drugs are facing price resistance. Michael Paranzino of the National Psoriasis Foundation notes that health insurers require patients to use standard therapies first. At least one health-care management company requires that patients suffer “physical impairment� before they try a biotech medication, he said.

Each of the medications has shortcomings; none works for every patient. Amevive requires weekly infusions over 12 weeks in a physician’s office at a cost of $7,000 to $10,000. Enbrel has been associated with an increased risk of infections in rheumatoid arthritis patients. Some patients who discontinue Raptiva develop worse cases of psoriasis than they had to start with.