On April 8, 2009, Genentech, the manufacturer of the psoriasis drug Raptiva (efalizumab), announced that it has begun a voluntary, phased withdrawal of the product from the U.S. market because of 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.

On February, 2009, the FDA issued a Public Health Advisory informing patients and prescribers of the risk of PML in patients taking Raptiva, after receiving reports of four patients with PML, three of whom died.

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 and often leads to an irreversible decline in neurologic function and death. There is no known effective treatment for PML. The drug was approved by the FDA in 2003; by June, 2009, Raptiva will no longer be available in the United States. Prescribers are being asked not to initiate Raptiva treatment for any new patients. The FDA strongly recommends that patients

work with their health care professional to transition to other alternative therapies for psoriasis; also prescribers should continue to monitor patients on Raptiva for neurologic symptoms that might represent PML.

You can visit www.fda.gov/bbs/topics/NEWS/2009/
New01992.htm

Efalizumab (trade name Raptiva, Genentech, Merck Serono) is a recombinant humanized monoclonal antibody that binds to CD11a and acts as an immunosuppressant. It is administered once weekly by subcutaneous injection. It acts to inhibit white blood cell migration out of blood vessels into tissues.

Due partly to the risks of PML, the European Medicines Agency recommended in February 2009 that efalizumab be suspended from sales in the European Union, deeming that its benefits no longer outweighed its risks.
Look at http://en.wikipedia.org/wiki/Efalizumab