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The FDA has announced that Biogen Idec is voluntarily suspending marketing of natalizumab (Tysabri) because of two serious adverse events reported with its use.

Biogen Idec voluntarily suspends natalizumab marketing

April 1, 2005

Biogen Idec voluntarily suspends natalizumab marketing

The FDA has announced that Biogen Idec is voluntarily suspending marketing of natalizumab (Tysabri) because of two serious adverse events reported with its use.

The FDA has received reports of one confirmed, fatal case and one possible case of progressive multifocal leukoencephalopathy (PML) in patients receiving natalizumab for multiple sclerosis. Although the relationship between natalizumab and PML is not known at this time, because of the rare, serious and often fatal nature of PML, FDA announced Biogen Idec no longer is going to market natalizumab and it is also suspending dosing of natalizumab in clinical trials. The company is notifying patients and investigators of the possible association between natalizumab and PML.

Patients being treated with natalizumab should contact their physician to discuss appropriate alternative treatments. At this time, there are no specific diagnostic or therapeutic interventions recommended for patients who have been taking natalizumab, other than to discontinue its use. Physicians should evaluate all patients who have received natalizumab and who have signs or symptoms suggestive of PML. Any suspect cases of PML should be reported immediately to Biogen Idec or to the FDA MedWatch program.

For more information, see www.fda.gov/medwatch/SAFETY/2005/safety05.htm#Tysabri.