FDA sees risks linked to the drug Tysabri

WASHINGTON, Feb. 8 (UPI) -- The U.S. Food and Drug Administration says it's determined the risk of developing a rare viral disease has been linked with Tysabri infusions.

The FDA said it has notified healthcare professionals the risk of developing progressive multifocal leukoencephalopathy increases with the number of Tysabri (Natalizumab) infusions received.

Tysabri is used to fight multiple sclerosis and Crohn's disease. Progressive multifocal leukoencephalopathy is a usually fatal disease that damages the material that covers and protects nerves in the white matter of the brain, Wikipedia said.

The new safety information is based on reports of 31 confirmed cases of PML received by the FDA as of January 21, officials said. The information is to be included on the Tysabri drug label and patient medication guide.

"Based on the available information, FDA believes that the clinical benefits of Tysabri continue to outweigh the potential risks," the federal agency said. "Revisions to the drug label and patient Medication Guide … are intended to maximize the safe use of Tysabri and the identification of new PML cases.

Tysabri is manufactured by Biogen Idec Inc. of Cambridge, Mass.

More information is available at http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm199965.htm.