EP News: Allied Professionals

The investigators (Milling TJ et al. Circulation 2023 online ahead of print. PMID: 36802866) offer the final report of ANNEXA-4 (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors), a multi-center, prospective study to assess the safety and efficacy of andexanet alfa in patients with major bleeding on factor Xa (FXa) inhibitors. A total of 479 patients (mean age 78 years, 54% male and 81% on oral anticoagulation for atrial fibrillation) were recruited from 85 centers in North America, Europe and Japan. Major bleeding was defined as one or more of the following: potentially life-threatening bleeding with signs of hemodynamic compromise, decrease in hemoglobin ≥ 2 g/dL from baseline or ≤8 g/dL if baseline hemoglobin unknown, or bleeding in critical area or organ (intracranial, retroperitoneal, pericardial, intra-articular, intramuscular). Included patients all took FXa inhibitor (apixaban, rivaroxaban, edoxaban or enoxaparin) within 18 hours of the major bleed. Andexanet alfa is given as a bolus over 15 minutes and follow-up infusion over 2 hours. Anti-factor Xa activity was measured before andexanet alfa was given (baseline), and then at end of bolus, end of infusion, and at 4, 8 and 12 hours after infusion. Study endpoints included change from baseline in anti-FXa activity with treatment, and hemostatic efficacy (control of bleeding) with treatment as assessed by an independent adjudication committee using prespecified criteria for excellent or good hemostatic efficacy. One such example of good or excellent hemostatic efficacy is ≤35% volume expansion in intracranial hemorrhage size after treatment. The primary safety endpoints were death and thrombotic events which were further stratified as occurring before or after restart of anticoagulation.