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The labelling of multiple sclerosis drug Tysabri (natalizumab) has been changed to point up the increased risk of contracting a potentially deadly brain infection.
The label changes specified that the occurrence of multifocal leukoencephalopathy (PML) in patients treated for 24 to 36 months is generally similar to the 1-in-1,000 rate seen in clinical trials, according to Ireland’s biggest drugs firm Elan.
Last month, European regulators began a review of the drug after reports of 23 cases of PML. Tysabri was temporarily withdrawn from the market in 2005 after being linked with PML.
It was reintroduced in July 2006 with stricter safety warnings, but shares in Elan and US pharmaceuticals firm Biogen Idec fell sharply after the most recent PML cases were reported last month.
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