Setbacks for multiple sclerosis drugs

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Biogen Idec yesterday added a warning to the labeling of its top-selling MS drug Avonex stating use of the drug can lead to severe liver problems including failure of the organ.
The warning comes under advisement from the FDA and on the heels of Biogen Idec's recall of its newer MS drug Tysabri two weeks ago. That warning was issued after two patients taking Tysabri in combination with Avonex developed a rare brain disorder.
In a letter posted on the FDA Web site, Biogen said severe liver injury, including liver failure, "has been rarely reported in patients taking Avonex." It said doctors should especially consider the risk when Avonex is used along with other drugs that can cause liver damage, or by patients who drink alcohol.
A spokeswoman for Biogen told the New York Times there had only been a handful of cases among the 130,000 patients using Avonex, which has been on the market since 1996, and that a "minor update" was being made to the drug's label, upgrading liver damage from a "precaution" to a stronger "warning."
Both Biogen and the FDA said there was no connection between the Avonex warning and the Tysabri withdrawal and that the timing was coincidental.
Meanwhile, GlaxoSmithKline said yesterday that the FDA ordered it to halt a trial of its multiple sclerosis drug, which works in a similar way to Tysabri.
A Glaxo spokesman told the New York Times he understood the halt was made as a precaution in trials of all drugs in the same class as Tysabri.
Glaxo was in Phase II of testing the drug 683699, which blocks the same protein as Tysabri. That drug was not being tested in combination with Avonex.
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