Keywords: Factor Xa inhibitor, reversal agent, adexanet alfa, andexxa (PubMed Search)
On May 3, the FDA approved adexanet alfa, the reversal agent for factor Xa inhibitors - apixaban and rivaroxaban. It received both U.S. Orphan Drug and FDA Breakthrough Therapy designations.
Unlike indarucizumab (a monoclonal antibody fragment) to reverse dabigatran (direct thrombin inhibitor) associated bleeding, adexanet alfa is a recombinant modified human factor Xa decoy protein.
A phase 3 study showed that adexanet alfa decreased the anti-factor Xa activity of rivaroxaban by 92% from baseline and by 94% in apixaban treated participants.
ANNEXA-4 study involving participants with acute major bleeding (GI and intracranial) showed a significant decrease in the anti-factor Xa activity after the bolus dose of adexanet alfa and "effective" hemostasis was noted in 79% of the participants at 12 hours post infusion.
Andexanet alfa is expected to become available in June 2018.