Tysabri Hold Lifted

The FDA has removed the hold on clinical trial dosing of Tysabri in multiple sclerosis (MS) in the U.S. Biogen Idec and Elan Corp. expect to begin an open label, multi-center safety extension study of Tysabri monotherapy in the U.S. and internationally in the coming weeks. Patients who previously participated in the Phase III MS program are eligible for entry.

Biogen Idec and Elan had previously voluntarily suspended Tysabri from the U.S. market and all ongoing clinical trials based on reports of progressive multifocal leukoencephalopathy (PML), a rare and potentially fatal, demyelinating disease of the central nervous system. The two companies completed a comprehensive safety evaluation of more than 3,000 Tysabri patients in collaboration with leading experts in PML and MS. The results of the safety evaluation yielded no new confirmed cases of PML beyond the three previously reported.

On September 26, 2005 the companies submitted a sBLA to the FDA and Tysabri was subsequently designated for Priority Review. The FDA grants Priority Review status to products that are considered to be potentially significant therapeutic advancements over existing therapies that address an unmet medical need. Based on the Priority Review designation, the companies anticipate action by the Agency approximately six months from the submission date, or by late March 2006.