EU clears anti-JC virus risk labeling for Biogen and Elan's Tysabri

US biotech firm Biogen Idec (Nasdaq: BIIB) and Ireland-based Elan (NYSE: ELN) said yesterday that the European Commission has approved the inclusion of anti-JC virus (JCV) antibody status as an additional factor to aid in stratifying patients at risk for developing progressive multifocal leukoencephalopathy (PML) in the Summary of Product Characteristics (SmPC) for their multiple sclerosis drug Tysabri (natalizumab) in the European Union.

In addition, as part of a standard review process, the EC concluded the quality, safety and efficacy of Tysabri continue to be adequately demonstrated and renewed the EU five-year Marketing Authorization.

The new SmPC language states that patients who are anti-JCV antibody positive are at an increased risk of developing PML compared to those who are anti-JCV antibody negative. Recent studies suggest that irrespective of MS treatment, approximately 55% of MS patients are anti-JCV antibody positive. The SmPC language also states that patients who are anti-JCV antibody positive, have received prior immunosuppressant (IS) therapy, and received treatment with Tysabri for more than two years have the highest risk of developing PML. The addition of anti-JCV antibody status to previously-established risk factors further stratifies the potential risk of developing PML.