Biogen Idec Inc., a biotechnology company, announced Friday that another patient who was taking its Tysabri multiple-sclerosis medicine is infected with progressive multifocal leukoencephalopathy, or PML. Their announcement marks the 13th case of the infection in patients taking Tysabri. Three other patients have already died from taking the medication and contracting PML. PML is a serious brain infection that attacks the central nervous system and damages and inflames the white matter areas of of the brain. Immune suppressing drugs such as Tysabri put patients at serious risk for contracting PML and potentially dying as a result.
Tysabri was pulled from the market back in 2005 after three initial cases of PML were discovered. After holding hearings on the drug’s risks and benefits, the Food and Drug Administration allowed Tysabri back onto the market in 2006 under new monitoring rules that the drug could not be combined with other MS drugs. The FDA had hoped that the new regulations would reduce the incidence of PML cases, but there have been ten new cases since.
Several other immune suppressing drugs have also contributed to the incidence of PML. In fact, Roche Holding AG pulled its psoriasis drug, Raptiva, over reports of PML. Similarly, Roche and Biogen has also come under increased scrutiny from the FDA over reports that its cancer treatment, Rituxan, increases the likelihood of contracting PML.
