FDA Delays Approval Decision for Factor Xa Inhibitor Antidote

Larry Hand

August 18, 2016

SOUTH SAN FRANCISCO, CA — The US Food and Drug Administration (FDA) has requested that Portola Pharmaceuticals provide additional information regarding manufacturing of its investigational drug andexanet alfa (AndexXa) prior to potential approval of the drug as a reversal agent for anticoagulants that work by inhibiting factor Xa, especially the new generation of oral agents with that mechanism of action[1].

Portola has filed a biologics license application for AndexXa, an FDA-designated breakthrough therapy, in development as a treatment for patients treated with factor XA inhibitors who present with life-threatening or uncontrolled bleeding.

The company's application is based on two phase 3 studies into the safety and efficacy of andexanet alfa as an antidote to the anticoagulant activity of rivaroxaban (Xarelto, Janssen) and apixaban (Eliquis, Bristol-Myers Squibb) in older healthy adults.

An ongoing phase 3b/4 study is evaluating andexanet alfa effects against apixaban, rivaroxaban, edoxaban (Savaysa, Daiichi-Sankyo), and enoxaparin.

In the FDA's current request, the agency also asked for additional data to support including edoxaban and enoxaparin in the drug's label.

Andexanet alfa, a derivative of factor Xa, as reported previously by heartwire from Medscape, has not been shown to have toxic effects.

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