Andexanet alfa for the treatment of hemorrhage.

While associated life-threatening and fatal bleeding events are less frequent with the direct factor Xa inhibitors compared to vitamin K antagonists, significant concern surrounding management of major bleeds and urgent periprocedural interruption of these agents exists among clinicians. Andexanet alfa is a recombinant human factor Xa decoy protein developed in response to this clinical gap in the care of patients receiving anticoagulation with factor Xa inhibitors. Areas covered: This paper reviews results from preclinical and healthy-volunteer studies demonstrating the ability of andexanet to rapidly and reliably normalize coagulation indices in patients treated with both direct and indirect factor Xa inhibitors. An interim analysis from an ongoing phase 3/4b clinical study assessing the efficacy and safety of andexanet in patients experiencing life-threatening hemorrhage in association with factor Xa inhibitors is discussed. It also provides an overview of the major safety concerns reported in these trials which include allergic and infusion reactions, development of anti-andexanet antibodies and, importantly, thrombosis. Expert commentary: While initial reports on restoration of hemostasis and safety are promising, further study of andexanet is required to gauge its efficacy and toxicity, including a potential prothrombotic effect. Further, its use in patients requiring urgent surgery should be studied.