[Andexanet alfa: the best antidote for factor Xa inhibitors?]

Abstract

Andexanet alfa (andexanet) was specifically developed to reverse factor Xa inhibitors. Its effect on patients who are experiencing major bleeding while being treated with an oral Xa inhibitor or low molecular weight heparin was studied in the ANNEXA 4 study. The main outcome of this study was that anti-factor Xa activity decreased during the 2-hour infusion with andexanet, and that 82% of patients had excellent or good haemostatic efficacy after 12 hours according to pre-specified criteria. Although andexanet is the only specific antidote for factor Xa inhibitors available, an alternative treatment may be high-dose prothrombin concentrate (PCC). With the recent approval by the European Medicines Agency (EMA) but unknown Dutch reimbursement status, the role of andexanet for daily clinical practice in the Netherlands remains to be determined. Notably, and importantly, when treating patients with anticoagulant-associated major bleeding, local haemostatic control and-if relevant-adequate fluid resuscitation are at least as important as choosing the optimal anticoagulation antidote.