Biotech firms Biogen Idec Inc. and Elan Corporation have submitted a supplemental Biologics License Application (sBLA) for Tysabri (which they had voluntarily suspended from the market in February) to the US FDA for the treatment of multiple sclerosis (MS).

The sBLA includes a final two-year data from the Phase III affirm monotherapy trial and sentinel add-on trial with Avonex (Interferon beta-1a) in MS, an integrated safety assessment of patients treated with Tysabri in clinical trials and a revised label and risk management plan, claims a company release.

The companies have requested Priority Review status for the sBLA, which, if granted, would result in action by the FDA approximately six months from the submission date, rather than 10 months for a standard review.

Biogen Idec and Elan will submit a similar data package to the European Medicines Agency (EMEA). This information will be supplied as part of the ongoing review process, which was initiated in the summer 2004 with the filing for approval of Tysabri as a treatment for MS.

On February 28, 2005, Biogen Idec and Elan had withdrawn Tysabri from the US market and all ongoing clinical trials based on reports of progressive multifocal leukoencephalopathy (PML), a rare and potentially fatal,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. Biogen Idec and Elan subsequently launched a comprehensive safety evaluation in collaboration with leading experts in PML and MS.