February 19, 2009 — Three deaths from progressive multifocal leukoencephalopathy (PML) and a possible fourth case have been reported in patients taking the immunosuppressant drug efalizumab (Raptiva, Genentech, Inc), according to a public health advisory issued today by the US Food and Drug Administration (FDA).

According to the FDA, all 4 patients had been taking efalizumab for at least 3 years and had taken no other immunosuppressant drugs.

The FDA is advising clinicians to follow patients who are receiving efalizumab closely, as well as those who have discontinued the drug, and to periodically reevaluate whether patients should continue to receive treatment.

A boxed warning was added to efalizumab in October 2008 to highlight the risk for life-threatening infection, including PML — a rare but incurable brain infection that leads to irreversible brain dysfunction and death.

The FDA is reviewing these cases of PML, according to an alert sent to today from MedWatch, the FDA's safety information and adverse event reporting program.

"The agency will take appropriate steps to ensure that the risks of Raptiva do not outweigh its benefits, that patients prescribed Raptiva are clearly informed of the signs and symptoms of PML, and that health care professionals carefully monitor patients for the possible development of PML," according to the public health advisory.

Efalizumab is an anti-CD11a antibody immunosuppressant drug indicated for the treatment of adults with chronic moderate to severe plaque psoriasis.

Adverse events related to use of efalizumab should be communicated to the FDA's MedWatch reporting program by telephone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at http://www.fda.gov/medwatch, or by mail to 5600 Fishers Lane, Rockville, Maryland 20852-9787.