Merck to return rights for betrixaban to Portola

Portola Pharmaceuticals and Merck (NYSE:MRK), known as MSD outside the United States and Canada, today announced that Merck plans to return to Portola all rights for betrixaban, an investigational oral Factor Xa inhibitor anticoagulant being evaluated for the prevention of stroke in patients with atrial fibrillation (SPAF). This decision was made following a review of Merck's investigational portfolio.

“As part of an ongoing prioritization of our late-stage pipeline, we have decided to return rights for betrixaban to Portola. Merck continues to advance its broad late-stage pipeline and remains committed to delivering medicines for cardiovascular disease.”

"Regaining full rights to betrixaban represents a transformational opportunity for Portola," said William Lis, chief executive officer of Portola. "We will work with our academic partners on options for an independent development plan to bring betrixaban to the market and intend to discuss these options with the FDA in the near future."

In July 2009, Merck and Portola announced an exclusive global collaboration and license agreement for the development and commercialization of betrixaban. Betrixaban most recently completed Phase II testing in the EXPLORE-Xa trial in which it showed dose dependent clinical activity with similar or lower rates of bleeding compared to warfarin in the study population. These results were presented during a late-breaking clinical trials session at the American College of Cardiology's 59th Annual Scientific Session in March 2010.

"Working closely with our Portola collaborators we have advanced betrixaban to this Phase III-ready stage," said Luciano Rossetti, M.D., senior vice president, Global Scientific Strategy at Merck. "As part of an ongoing prioritization of our late-stage pipeline, we have decided to return rights for betrixaban to Portola. Merck continues to advance its broad late-stage pipeline and remains committed to delivering medicines for cardiovascular disease."