TYSABRI SBLA GRANTED PRIORITY REVIEW

The FDA has granted priority review status to Elan and Biogen Idec's supplemental biologics license application (sBLA) for Tysbari, clearing the way for the agency to issue a decision on the drug by late March 2006.

The firms filed an sBLA with the FDA Sept. 26, seeking permission to return Tysabri (natalizumab) to the market as a treatment for multiple sclerosis (MS). The filing came roughly seven months after Biogen and Elan voluntarily suspended marketing and clinical use of Tysabri, following reports that three patients taking the drug in a clinical trial contracted progressive multifocal leukoencephalopathy (PML), a rare and frequently fatal demyelinating disease of the central nervous system.

The sBLA includes final two-year data from the sponsors' Phase III AFFIRM trial, an integrated safety assessment of patients treated with Tysabri in clinical trials, a revised label and a risk management plan.

Priority review status obligates the FDA to act on a drug application within six months of the submission date, rather than 10 months for a standard review.