Biogen and Elan seek additional labeling for MS drug Tysabri to test for PML

USA-based Biogen Idec (Nasdaq: BIIB) and Irish marketing partner Elan (NYSE: ELN) have submitted a supplemental Biologics License Application to the US Food and Drug Administration and a Type II Variation to the European Medicines Agency (EMA) to request review and approval to update the respective Prescribing Information and Summary of Product Characteristics for their multiple sclerosis drug Tysabri (natalizumab).

The companies are proposing updated product labeling to include anti-JC Virus antibody status as one potential factor to help stratify the risk of progressive multifocal leukoencephalopathy (PML), a rare but serious brain infection, in the Tysabri-treated population. These filings are part of the companies’ ongoing commitment to actively identify and address potential risk factors for PML in Tysabri-treated patients, they said.

US Food and Drug Administration had previously found that the risk of a potentially fatal brain disorder with the firm’s multiple sclerosis drug Tysabri (natalizumab) increases as patients receive more infusions and called for stronger warnings (The Pharma Letter February 8). The agency did, however, reiterate its views that the benefits for MS patients associated with the drug still outweigh the risks. Back in 2005 Biogen and Elan pulled the drug from the market when the first two cases of PML were reported. The companies later resumed marketing, but with warnings on the use of the product.