Portola Pharma: Phase 3 ANNEXA-A Study Of Andexanet Alfa, Eliquis Met Endpoints

(RTTNews) - Portola Pharmaceuticals (PTLA) reported that its first Phase 3 study of andexanet alfa, a potential universal Factor Xa inhibitor antidote and U.S. Food and Drug Administration-designated breakthrough therapy, achieved its primary and secondary endpoints with high statistical significance. Andexanet alfa was well tolerated with no serious adverse events reported.

Top-line efficacy data from the first of two Andexanet Alfa a Novel Antidote to the Anticoagulant Effects of fXA Inhibitors - Apixaban or ANNEXA-A trials showed that an intravenous or IV bolus of andexanet alfa immediately and significantly reversed the anticoagulation activity of Bristol-Myers Squibb Co. (BMY) and Pfizer Inc.'s (PFE) direct Factor Xa inhibitor Eliquis, the company noted.

John Curnutte, M.D., executive vice president of research and development for Portola stated, "These highly statistically significant Phase 3 ANNEXA-A data demonstrate that andexanet alfa has the potential to be the first agent approved as a universal Factor Xa inhibitor antidote. We anticipate filing a Biologics License Application with the FDA for Accelerated Approval at the end of 2015." He added, "We expect to report additional data this year and next with other Factor Xa inhibitors, including rivaroxaban, edoxaban, betrixaban and enoxaparin."

The randomized, double-blind, placebo-controlled Phase 3 ANNEXA-A studies are assessing the safety and efficacy of andexanet alfa in reversing Eliquis-induced anticoagulation in older healthy volunteers.

In the first ANNEXA-A trial, reported today, 33 older healthy volunteers were given Eliquis 5 mg twice daily for four days and then randomized in a 3:1 ratio to andexanet alfa administered as a 400 mg IV bolus or to placebo. The study met both its primary and secondary endpoints with high statistical significance. Results demonstrated that andexanet alfa immediately and significantly reversed the anticoagulation activity of Eliquis.

In the second ANNEXA-A study, 32 healthy volunteers would be given Eliquis 5 mg twice daily for four days and then randomized in a 3:1 ratio to andexanet alfa administered as a 400 mg IV bolus followed by a continuous infusion of 4 mg/min for 120 minutes or to placebo. These data are expected in early 2015.