A prespecified analysis from the AZALEA-TIMI 71 trial highlights that the novel factor XI inhibitor abelacimab significantly reduces the bleeding risk compared to rivaroxaban in patients with atrial fibrillation (AF), regardless of concomitant use of antiplatelet therapy (APT). The findings published in the Circulation provide evidence that abelacimab may be a safer anticoagulation strategy for AF patients who require APT due to underlying cardiovascular conditions.
The analysis included 1,287 AF patients (median age, 74) randomized to receive either monthly subcutaneous abelacimab (90 mg or 150 mg) or daily oral rivaroxaban (20 mg or 15 mg, based on renal function). Among them, 318 patients (24.7%) were on APT, primarily aspirin or P2Y12 inhibitors.
In patients receiving rivaroxaban, major or clinically relevant nonmajor bleeding occurred at a rate of 10.6% per 100 patient-years with APT and 7.7% without. In contrast, bleeding rates with abelacimab remained low across both APT and non-APT subgroups. In patients receiving concomitant antiplatelet therapy (APT), the rates of major or clinically relevant non-major bleeding were 2.5% per 100 patient-years with abelacimab 90 mg and 3.5% with abelacimab 150 mg. Among those not receiving APT, the corresponding bleeding rates were 2.7% for abelacimab 90 mg and 3.1% for abelacimab 150 mg.
Compared with rivaroxaban, abelacimab reduced bleeding risk by up to 74% in patients with APT (HRs 0.26 and 0.30 for 90 mg and 150 mg doses, respectively). The relative reductions were consistent in those without APT, and interaction testing confirmed that efficacy was not modified by APT status (P_interaction > 0.5 for both doses). The study reported a greater reduction in absolute risk among those on APT.