December 15, 2008
New Brain Infection Linked To Multiple Sclerosis Drug
On Monday, Biogen Idec Inc said it notified regulators of a new case of a potentially deadly brain disease in a patient being treated with its Tysabri multiple sclerosis drug, the fourth such case reported globally this year.
Biogen stated in a regulatory filing that the latest case of the brain infection, known as progressive multifocal leukoencephalopathy (PML), was seen in a European patient that had been taking Tysabri as a stand-alone treatment for 26 months.
Company spokeswoman Shannon Altimari said the patient is under physician's care and it was too soon to speculate on the prognosis for the patient.
Both Biogen and Elan shares fell sharply after the companies disclosed on October 29 that a case of PML had been seen in a U.S. patient. In July, the companies reported two cases had emerged in Europe.
The four cases from this year are the first to be announced since Tysabri was withdrawn from the market in 2005 after three earlier patients developed the brain infection.
Biogen spokeswoman Naomi Aoki said on Monday that no cases were seen in 2006 or 2007 because the drug had been taken off the market for a little over a year, and returned in July 2006.
Biogen and Elan believe the superior effectiveness of Tysabri in preventing relapses of multiple sclerosis symptoms justifies its use, despite the relatively low risk of PML, Aoki said.
About 35,000 patients worldwide are taking Tysabri, and that the drug in clinical trials was able to produce a 68 percent reduction in relapses.
She said rival drugs, by contrast, are able to reduce relapses by only about a third.
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