CAMBRIDGE, Mass. & DUBLIN, Ireland--(BUSINESS WIRE)--Biogen Idec (NASDAQ: BIIB) and Elan Corporation, plc (NYSE: ELN) announced today the one-year anniversary of TYSABRI® (natalizumab) as a treatment for relapsing forms of multiple sclerosis (MS). One year following its return to market in the US and introduction in the European Union, the companies estimate that as of mid-July 2007 in both commercial use and clinical trials approximately 14,000 patients are currently on TYSABRI therapy worldwide.
