NEW ORLEANS and SOUTH SAN FRANCISCO, Calif., Nov. 14, 2016 (GLOBE NEWSWIRE) -- Portola Pharmaceuticals, Inc. ® (Nasdaq:PTLA) today announced results from three substudies of the pivotal Phase 3 APEX Study of betrixaban, an oral, once-daily Factor Xa inhibitor anticoagulant in development for the prevention of venous thromboembolism (VTE) in acute medically ill patients. Findings from the analyses were presented by the PERFUSE Study Group at the American Heart Association (AHA) Scientific Sessions 2016. In a retrospective APEX substudy on stroke, researchers assessed the potential of extended-duration thromboprophylaxis with betrixaban compared with standard-dose enoxaparin to reduce the risk of stroke in hospitalized acute medically ill patients. The substudy found that extended-duration betrixaban significantly reduced all-cause stroke (0.54 percent for betrixaban vs. 0.97 percent for enoxaparin; RRR=44 percent) and ischemic stroke (0.48 percent for betrixaban vs. 0.91 percent for enoxaparin; RRR=47 percent) through 77 days of follow up. The results were presented today by C. Michael Gibson, M.S., M.D., in the Sol Sherry Distinguished Lecture in Thrombosis at AHA and simultaneously published in the peer-reviewed journal Circulation. "Stroke is a potentially fatal complication, but little is known about the effectiveness of novel oral anticoagulants in preventing stroke among the acute medically ill patient population. We were encouraged to find that betrixaban was associated with a reduction in the risk of all-cause stroke within 30 to 60 days, which was driven predominantly by a reduction in ischemic stroke, without an increased risk of major bleeding," said Dr. Gibson, APEX Executive Committee Member and Steering Committee Chairman; professor, Harvard Medical School; and chairman of the PERFUSE Study Group. "The unique properties of betrixaban may, in part, explain the observed reduction in stroke without an increase in major bleeding in this study population. These findings are especially important because they demonstrate the potential for betrixaban to improve stroke outcomes in these patients."