Genentech  is removing its psoriasis drug Raptiva from the U.S. market through a phased withdrawal.  The company said there’s a potential risk to patients of developing progressive multifocal leukoencephalopathy (PML), a rare, serious, progressive neurologic disease caused by a virus that affects the central nervous system.

By June 8, 2009, Raptiva will no longer be available in the United States. This transition period will allow patients currently taking Raptiva to work with their doctors to discontinue use of the drug.  Because of the potential for severe psoriasis worsening with abrupt discontinuation of Raptiva, it is important that patients talk with their doctor before stopping treatment, Genentech said.

Doctors are being asked not to begin Raptiva treatment for any new patients.

The risk that an individual patient taking Raptiva will develop PML is rare and is generally associated with long-term use. Generally, PML occurs in people whose immune systems have been severely weakened.

On Oct. 16, 2008, the Food and Drug Administration updated  labeling for Raptiva to warn of the risk of life-threatening infections, including PML. On Feb. 19, 2009, the FDA issued an advisory informing Raptiva patients and prescribers of the risk of PML after receiving reports of four patients with PML, three of whom died.

Genentech estimates that approximately 2,000 patients in the United States may currently be receiving Raptiva for chronic plaque psoriasis. Since FDA approval in 2003, approximately 46,000 patients worldwide have been treated with Raptiva.