Back earlier this year, when some bad results had come out about Merck's thrombin receptor antagonist, I wrote ". . .another result like this one, and vorapaxar could be completely sunk". Well, perhaps it is. Merck has unveiled the results of a large Phase III trial in 13,000 at-risk patients, and the drug failed completely to beat a placebo control. Moreover, there were higher bleeding risks in the treatment group, and theh follow-up phase of the trial was terminated early for safety reasons. There are a lot of potential markets for an anticoagulant, and a lot of trials that can potentially be run, but this compound is in a great deal of trouble at the very least.
Meanwhile, at the same AHA meeting, Pfizer and BMS had the unpleasant job of announcing that their anticoagulant hope, apixaban, did not beat heparin (in the form of enoxaparin, Lovenox) for protection against cardiovascular events. About 5,000 patient participated in that study.
You can see from this sort of news how much fun it is to work in the anticoagulant field. Great big expensive trials await you, and the standard of care is surprisingly hard to beat. That's not to say that the standard is so wonderful - physicians would be glad to ditch things like warfarin and heparin. But they're still out there, and with Plavix going generic, the cost/benefit bar isn't going down any, either.
One big drug that actually did provide some good news was the Bayer Factor Xa inhibitor rivaroxaban (Xarelto). That one did manage to beat placebo in post-heart-attack patients (a mere 15,500 of them), albeit with, again, an increased risk of bleeding. Overall, though, it was a grim weekend for a lot of big clinical programs.