What is the purpose of Andexanet Alfa?
Andexanet Alfa is a specific reversal agent for direct (apixaban, rivaroxaban, and edoxaban) and indirect (low-molecular-weight heparins [LMWHs] and fondaparinux) factor Xa inhibitors that act through antithrombin. It is a modified human recombinant factor Xa decoy protein that is catalytically inactive due to replacement of an active-site serine with alanine and with deletion of the membrane binding domain, which eliminates the ability to assemble the prothrombinase complex. Andexanet retains the ability to bind to NOACs with high affinity and a 1:1 stoichiometric ratio and by sequestering factor Xa inhibitors within the vascular space, endogenous factor Xa activity is restored. Due to its pharmacodynamic half-life of 1 hour, Andexanet is administered as a bolus followed by an infusion.