when was tysabri fda approved
WebMD News Archive. June 5, 2006 -- The FDA is letting the multiple sclerosis (MS)multiple sclerosis (MS) drug Tysabri back on the market under a restricted distribution program. The FDA first approved Tysabri in November 2004. Tysabriâs maker, Biogen-Idec, took Tysabri off the market in February 2005 after three people out of about 3,000 patients taking Tysabri in clinical trials developed a rare, serious brain infection called progressive multifocal leukoencephalopathy (PML).