Portola, Bristol-Myers Report Results Of 2-nd Part Of Phase 3 ANNEXA-A Study

(RTTNews) - Portola Pharmaceuticals (PTLA), Bristol-Myers Squibb Co. (BMY) and Pfizer Inc. (PFE) announced full results from the second part of the Phase 3 ANNEXA-A (Andexanet Alfa a Novel Antidote to the Anticoagulant Effects of FXa Inhibitors - Apixaban) study.

The registration-enabling study evaluated the safety and efficacy of andexanet alfa, an investigational antidote and U.S. Food and Drug Administration (FDA)-designated breakthrough therapy, administered as an intravenous (IV) bolus followed by a continuous two-hour infusion to sustain the reversal of anticoagulation activity of the Factor Xa inhibitor Eliquis (apixaban) in healthy volunteers ages 50-75 years.

This second part of the study achieved all primary and pre-specified secondary endpoints with high statistical significance. Andexanet alfa produced rapid reversal of the anticoagulant effect of Eliquis, as measured by anti-Factor Xa activity, which was sustained for the duration of the infusion. Andexanet alfa significantly reduced the level of free unbound Eliquis in the plasma and restored thrombin generation to normal.

Andexanet alfa was well tolerated, with no serious adverse events, thrombotic events, or antibodies to Factor X or Xa reported. Mild infusion reactions were reported in six subjects: four in the andexanet arm and two in the placebo arm. No subjects discontinued the study due to an adverse event.

Portola plans to submit data from the ANNEXA-A (apixaban) and ANNEXA-R (rivaroxaban) studies, and initial data from a Phase 4 study, as part of its Biologics License Application (BLA) to the FDA under an Accelerated Approval pathway by the end of 2015.