The news of 43 confirmed cases of post-marketing Natalizumab-related PML coincides with the timely publication of the description of the first 28 such cases and a review on the topic:
Clifford DB, et al. Natalizumab-associated progressive multifocal leukoencephalopathy in patients with multiple sclerosis: lessons from 28 cases. Lancet Neurol. 2010 Apr;9(4):438-446.
Tan CS, Koralnik IJ. Progressive multifocal leukoencephalopathy and other disorders caused by JC virus: clinical features and pathogenesis. Lancet Neurol. 2010 Apr;9(4):425-437.
These developments underpin the urgent efforts to implement an appropriate risk-stratification strategy to lower the risks of developing PML for people with MS receiving Natalizumab.
Please watch this space for an update.