ANNEXA-R: Antidote to novel oral anticoagulant met primary endpoint

Portola Pharmaceuticals announced topline results of the phase 3 ANNEXA-R study demonstrating that andexanet alfa, an antidote to the anticoagulant effects of Factor Xa inhibitors, met the primary endpoint with high statistical significance.

According to a company press release, an IV bolus of andexanet alfa was associated with significant and immediate reversal of the anticoagulant activity of rivaroxaban (Xarelto, Janssen Pharmaceuticals) in the first part of the ANNEXA-R study. Andexanet alfa also was well tolerated.

The first part of this study included 41 healthy volunteers aged 50 to 75 years who received 20 mg once-daily rivaroxaban for 4 days followed by random assignment to placebo (n=14) or an 800 mg IV bolus of andexanet alfa (n=27). The primary endpoint was anti-Factor Xa levels.

Portola Pharmaceuticals expects to present the full data set at the American College of Cardiology Scientific Sessions in March.

The second, ongoing part of the ANNEXA-R study will include 40 healthy volunteers who will receive 20 mg once-daily rivaroxaban for 4 days and will then be randomly assigned to placebo or an 800 mg IV bolus of andexanet alfa followed by a continuous infusion of 8 mg/min for 120 minutes. Data from the second part of this study are anticipated in mid-2015.

Source: www.healio.com