Wednesday, July 20

TYSABRI Phase III Induction Trial in Crohn's Disease Meets Primary Endpoint; TYSABRI Induced Statistically Significant Response and Remiss

Elan Corporation, plc and Biogen Idec announced today that ENCORE, the second Phase III induction trial of TYSABRI(R) (natalizumab) for the treatment of moderately to severely active Crohn's disease (CD) in patients with evidence of active inflammation, met the primary endpoint of clinical response as defined by a 70 point decrease in baseline Crohn's Disease Activity Index (CDAI) score at both weeks 8 and 12.On February 28, 2005, Elan Corporation, plc and Biogen Idec announced that they voluntarily suspended TYSABRI from the U.S. market and all ongoing clinical trials. This decision was based on reports of progressive multifocal leukoencephalopathy (PML), a rare and potentially fatal, demyelinating disease of the central nervous system. Elan and Biogen Idec's comprehensive safety evaluation concerning TYSABRI and any possible link to PML is ongoing. At the time of the dosing suspension, all ENCORE study patients had completed dosing based on the study protocol and collection and analysis of data followed.