Biogen Idec ( BIIB - Analyst Report ) recently announced that Health Canada has approved a change in the label of its multiple sclerosis (MS) drug, Tysabri. The new label of the drug indicates anti-JC virus (JCV) antibody status as a risk factor for developing a rare, serious brain infection known as progressive multifocal leukoencephalopathy (PML). Infection by the JC virus leads to the development of PML.

This is the third risk factor identified by Biogen for MS patients on treatment with Tysabri. It helps assess the benefit-risk profile of the drug, ensuring that physicians and patients make more informed choices in treating a debilitating disease like MS. Patients who are anti-JCV antibody positive, have received prior immunosuppressant therapy and have been treated with Tysabri for more than two years are most likely to develop PML.

Prior to the Canadian approval for the label update the U.S. Food and Drug Administration and the European Commission had approved anti-JCV antibody status as a means of identifying patients at a higher risk of contracting PML. Biogen said that 59,000 anti-JCV antibody tests were conducted through the third quarter of 2011.

Tysabri recorded global sales of $1.5 billion in 2011. Tysabri is approved in more than 65 countries and faces stiff competition from Teva Pharmaceutical Industries Limited’s ( TEVA - Analyst Report ) Copaxone, Pfizer Inc. ( PFE - Analyst Report ) /Serono’s Rebif and Novartis’ ( NVS - Snapshot Report ) Extavia. Tysabri is facing additional competition in the form of Novartis’ Gilenya, which was launched in early Oct 2010.

Our Take

The updated label should help increase awareness about the antibody status of both existing as well as prospective patients.

With the updated label, Biogen should be in a position to approach neurologists and provide the MS community with more confidence when considering treatment options.

We currently have a Neutral recommendation on Biogen in the long run. Biogen carries a Zacks #3 Rank (Hold rating) in the short run.