In February 2009, the FDA issued a public health advisory that patients taking the psoriasis medication Raptiva manufactured by Genentech were at risk of developing a potentially fatal condition known as PML, or progressive multifocal leukoencephalopathy. As explained on Wikipedia, PML
"is a rare and usually fatal viral disease that is characterized by progressive damage or inflammation of the white matter (a/k/a myelin) of the brain at multiple locations. It occurs almost exclusively in people with severe immune deficiency."
The effects of Raptiva decrease the function of the immune system and increase susceptibility to infections (incidentally, PML is the same disease that has been linked to the multiple sclerosis drug Tysabri, sold by Biogen Idec and Elan).
Earlier this week, the FDA announced that Genentech had begun a voluntary, phased withdrawal of Raptiva from the U.S. market due to the potential risk to patients of developing PML from using the medication. By June 8, 2009, Raptiva will no longer be available in the United States.
The FDA also said it had asked prescribers not to initiate Raptiva treatment for any new patients, and immediately begin discussing with patients currently using Raptiva on how to transition to alternative therapies for psoriasis.