Bleeding forces Pfizer, BMS to halt apixaban study

Pfizer ($PFE) and Bristol-Myers Squibb ($BMS) have discontinued a 10,800-person Phase III trial of the blood thinner apixaban in patients with acute coronary syndrome treated with apixaban in addition to mono or dual antiplatelet therapy. The companies observed increased bleeding among patients taking apixaban, which was not offset by a decreased in ischemic events. Pfizer and BMS didn't share the number or severity of the adverse events.

The APPRAISE-2 study, as it was called, was just one of nine separate trials evaluating apixaban for a variety of ailments. BMS' Brian Daniels, senior vice president, Global Development and Medical Affairs, said the companies are committed to continuing development of the drug. "We are focused on the rolling submission of data for the prevention of stroke in patients with atrial fibrillation who are expected or demonstrated to be unsuitable for treatment with warfarin to the FDA and the application to the EMA for venous thromboembolism prevention."

Apixaban is one of a number of new oral anticoagulants, including Boehringer Ingelheim's Pradaxa and Xarelto from Bayer and Johnson & Johnson, hoping to compete against existing blood thinners. Apixaban targets a protein called Factor Xa, which plays a role in the development of blood clots. In 2007 Pfizer agreed to pay $250 million up front and up to $750 million in milestones to partner with BMS on the drug.

- here's the Pfizer release
- read the Reuters coverage for more