Biogen, Elan report no new PML cases in Tysabri review

Shares of Biogen Idec and Elan surged on the news that a review of patients taking Tysabri for multiple sclerosis revealed no new cases of a rare brain disease -- PML -- that killed two and afflicted a third. The drug companies had pulled Tysabri from the market last February after the drug was linked to the disease. The review included about 1,800 patients who had taken the drug in clinical trials. Now the company says it is taking preliminary steps to restart trials on Tysabri for MS.

"Given the high unmet medical need in MS and the therapeutic benefit we have seen with Tysabri, we are encouraged by these safety findings," the companies said. "We look forward to working with regulatory authorities to determine the path forward for Tysabri."

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