Portola, Merck report postitive betrixaban results

Fierce 15 company Portola Pharmaceuticals and Merck today announced the results of a Phase II dose-finding study of betrixaban at the American College of Cardiology meeting. In the study, a once-daily dose of oral betrixaban, given to patients with non-valvular atrial fibrillation or atrial flutter and at least one risk factor for stroke, reduced incidence of bleeding compared with warfarin. Betrixaban is part of a new class of drugs called factor Xa inhibitors that block an enzyme that causes clotting.

Merck and Portola inked a $470 million deal for the drug last year in which Portola got $50 million upfront. At that time Merck assumed all responsibility for development costs for the drug, including late-stage trials.

"Given that bleeding can be a significant safety issue for patients who take warfarin, there is a critical unmet need for anticoagulant therapy options," says U.S. national coordinator in the study, Michael Ezekowitz in a statement. "The EXPLORE-Xa study accomplished its objective of providing important information to guide the betrixaban dosing strategy for future investigational studies."

Other developers have their own factor Xa inhibitor drugs in the pipeline. Boehringer Ingelheim and Bayer already have European approval for Praxada and Xarelto, respectively, while Bristol-Myers Squibb and Pfizer have partnered on the anticoagulant apixaban.

- read Portola release
- check out this BusinessWeek story for more