Biogen Idec Inc. (Nasdaq:BIIB) has disclosed that 10 more patients taking the multiple sclerosis drug Tysabri have contracted the rare brain infection known as PML. The Weston-based biotech company says the total number of cases of the infection, which can be fatal, is 95, as of Feb. 2. The total number of deaths is 20.
The incidence of PML (progressive multifocal leukoencephalopathy) has now risen above the 1-in-1,000 average that appears on the warning label of the drug; however, Biogen executives have said that the incidence is so slightly above – at 1.16 per 1,000 patients – that it is statistically insignificant.
