Biz Brief: Stroke Drug Study Ends Early on Positive Result

Pfizer (PFE) and Bristol-Myers Squibb (BMY) said on Thursday that they've decided to halt a clinical trial several months early because data so far suggested an experimental drug was more effective than aspirin in preventing strokes among patients. Both companies' shares rose over 2% by 11:15 a.m.

Interim data from the large, late-stage study of their experimental blood-clot preventer apixaban found "clear evidence" of a reduction in stroke and blood clots in patients with irregular heart rhythms. The drug also had an "acceptable safety profile compared to aspirin," the companies said.

Barclays recently estimated the market for these kind of drugs could reach $12 billion by 2021, and apixaban alone could generate peak annual sales of about $3.6 billion, the Dow Jones Newswire reported. Bristol-Myers hopes to launch the drug in 2012.

Jefferies and Soleil reiterated buy rating on Pfizer, while Citigroup upgraded BMS to buy from hold.