Reversal Agent for Factor Xa Inhibitors Under FDA Review

Portola Pharmaceuticals announced the submission of a Biologics License Application (BLA) to the Food and Drug Administration (FDA) for its investigational agent andexanet alfa, as a universal reversal agent for patients anticoagulated with an oral or injectable Factor Xa inhibitor who experience a serious uncontrolled bleeding event or who require urgent or emergency surgery. There is currently no FDA-approved antidote for Factor Xa inhibitors for these patients.

The BLA submission is based on data from Phase 3 ANNEXA (Andexanet Alfa a Novel Antidote to the Anticoagulant Effects of FXa Inhibitors) studies which evaluated the safety and efficacy of andexanet alfa in reversing the anticoagulant activity of the Factor Xa inhibitors rivaroxaban and apixaban in healthy volunteers. Study results were published online by The New England Journal of Medicine in November 2015.

RELATED: Andexanet Alfa Can Reverse Effect of Factor Xa Inhibitors

Portola is currently evaluating andexanet alfa in a global Phase 4 confirmatory study, ANNEXA-4, in patients receiving apixaban, rivaroxaban, edoxaban or enoxaparin (a low molecular weight heparin and indirect Factor Xa inhibitor) who present with an acute major bleed. Data from a small number patients in this study will serve as the clinical basis for the BLA.

Andexanet alfa is a modified human Factor Xa molecule that acts as a decoy to target and sequester with high specificity both oral and injectable Factor Xa inhibitors, preventing the inhibition of native Factor Xa, thus allowing for the restoration of normal hemostatic processes.

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