Tysabri Linked to 2 New Brain Infections

Tysabri was pulled from the US market in 2005 after the MS drug had been linked to a rare but dangerous drug infection, progressive multifocal leukoencephalopathy (PML). Biogen, Tysabri’s manufacturer has revealed that 11 brain infection cases have been linked to Tysabri since the drug came back on the market in 2006. Both cases come from Europe.
While Tysabri has been known to successfully treat the symptoms of multiple sclerosis, prolonged use of the drug has been associated with PML. The New England Journal of Medicine reported the latest 2 brain infections and noted a study by Dr. Igor Koralnik of Harvard Medical Center that showed an increase in the virus that causes PML in patients that took Tysabri for a year or longer.
Tysabri, marketed jointly by Biogen and the Irish company Elan Corp Plc, is popular with MS patients as well as doctors. It’s estimated that some 43,000 patients are currently using the drug. Tysabri is an important drug in the Biogen family of pharmaceuticals and has been responsible for a large part of the company’s profits so it comes as no surprise the company is downplaying this latest New England Journal of Medical report.