Tysabri safety falls under EMEA scrutiny

European regulators are taking a hard look at the multiple sclerosis wonder drug Tysabri. Spurred by 23 cases of the brain disease PML that have cropped up since Tysabri went back on the market in 2006, EMEA watchdogs will review the drug's record. And they'll consider whether "additional measures" should be taken to ensure Tysabri's safety.

The MS drug has been both a boost and a bane for Biogen Idec and Elan. They've enjoyed fast sales growth and zealous patient support, but they've also suffered from a market withdrawal and ongoing fears, both prompted by progressive multifocal leukoencephalopathy. After its 2005 U.S. withdrawal, the drug came back onto the market under a strict risk-management program, and company officials warned that PML probably would resurface. And it has.

Now, company officials and regulators know more about PML symptoms and treatment. Biogen hopes that better diagnosis and treatment could mitigate some of the safety fears. And so far, the FDA has stood behind the drug's current labeling, But 23 new PML cases have given FDA and its European counterparts pause. FDA is negotiating with Biogen on potential changes to Tysabri's U.S. label, warning that long-term use could increase the risk of PML. And now the EMEA has launched its review. We'll see how that goes.

- see the EMEA release
- get the news from MarketWatch
- check out the Wall Street Journal article