anti-clotting

When Merck halted a late-stage study of its potential clot-preventing drug vorapaxar in stroke victims last week, it didn't explain why. Now, the company has confirmed it stopped the study after concerns that the drug increased the risk of bleeding in some patients.

Several recent studies of drugs used to treat and prevent strokes appear to favor AstraZeneca's (AZN) Brilinta and Eli-Lilly's (LLY) Effient over Plavix. Plavix, co-marketed by Bristol-Myers Squibb (BMY) and Sanofi-Aventis (SNY), is the second best-selling drug in the world.

AstraZeneca (AZN) has had a good week with its anticlotting drug Brilinta (ticagrelor). It impressed many observers by announcing positive results of a late-stage head-to-head study and a mid-stage study for Brilinta, and on Thursday, it said it had filed for Food and Drug Administration approval....