Tysabri Dangers to be Investigated in Europe
On October 22, 2009, a European panel announced that has started reviewing the controversial multiple sclerosis drug Tysabri, sold by Biogen Idec Inc. and Elan Plc, as a result of a much higher rate of a rare brain infection than earlier divulged. In a statement, the European Medicines Agency’s Committee for Medicinal Products for Human Use, reported that there are 23 cases of progressive multifocal leukoencephalopathy, or PML, since the drug’s launch.
Previously, there had only been 13 cases of the infection since the drug re-entered the market in 2006, following an 18-month removal that was prompted by a link to three previous cases of PML. The European panel said its review will discuss “any additional measures necessary to ensure the safe use of Tysabri and how to balance the risks to the patients against the benefits of the treatment.”
Earlier in the week of October 19, 2009, Biogen acknowledged that it is talk with the U.S. FDA to amend Tysabri’s label to reflect increased PML risk with longer-term usage. Changing the label marks a shift for Biogen, which has long maintained there was no clear connection to duration and increased risk of PML, but mounting evidence has made that link clear.
The company continues to believe that the rate of PML remains consistent with the 1-in-1,000 patient rate implied in the label. As of Sept. 30, about 46,200 people worldwide were taking Tysabri with about 13,400 patients on the drug for more than 24 months.
Last month, the FDA updated the drug’s safety information, warning that PML risk seems to increase with infusions, noting that the average number of monthly infusions received before the diagnosis of PML was 25.
