2nd UPDATE: FDA Warns Of PML Risk With Psoriasis Drug Raptiva

The Food and Drug Administration Thursday warned patients on the psoriasis drug Raptiva about the risk of developing a rare and often fatal brain infection known as progressive multifocal leukoencephalopathy.

In a public health advisory posted on the agency's Web site, the FDA said it's received three confirmed and one possible report of PML in patients taking Raptiva since the drug was approved in 2003. Raptiva is marketed by Genentech (DNA) and is approved to treat a condition characterized by inflamed, swollen and scaly patches of skin. The agency said three of the patients died.

Separately, the European Medicines Agency recommended the drug be withdrawn from the European market because of the risk of PML. Merck Serono, a division of Germany's Merck KGaA (MRK.XE), sells Raptiva in Europe while Genentech sells the drug in the U.S. The European Commission must sign off on the recommendation to make it official, which is expected.

Last October the U.S. product labeling for Raptiva was revised to highlight in a boxed warning the risks of life-threatening infections, including PML, after one case of PML was seen.

The FDA said it is reviewing the additional cases of PML "and will take appropriate steps to ensure that the risks of Raptiva do not outweigh its benefits."

"The FDA strongly recommends that health care professionals carefully monitor patients on Raptiva, as well as those who have discontinued the drug, for any signs or symptoms of neurologic disease, and that they periodically reassess the benefits of continued treatment," the agency said in a statement. The FDA noted that there are several other approved products to treat psoriasis.

A Genentech spokeswoman said the company takes "the risk of PML very seriously and [is] working diligently with the FDA to put the right plans in place that will help protect patient safety." Last week Genentech sent out a letter to health care professionals discussing the third case of PML.

The FDA said four patients were treated with the drug for more than three years. None of the patients were receiving other treatments that suppress the immune system.

PML is caused by a virus that affects the central nervous system. PML usually occurs in people whose immune systems have been severely weakened, and there's no treatment or known way to prevent the condition. PML leads to an irreversible decline in neurologic function and death.

Symptoms may include unusual weakness, loss of coordination, changes in vision, difficulty speaking and personality changes, the FDA said.

Raptiva was approved in 2003 to treat adults with moderate to severe plaque psoriasis and there were no reports of PML seen in clinical trials. The drug is a once-weekly injection and works by suppressing T-cells in the immune system to keep the body from producing excess skin cells which causes the scaly, build-up of plaques in people with severe psoriasis. However, by suppressing T-cells, Raptiva also decreases the function of the immune system which increases a patient's susceptibility to infections.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; [e-mail].