Key result
Abelacimab shows no significant peri-procedural bleeding benefit over rivaroxaban in AF.
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Why the study?
To examine periprocedural bleeding among patients with AF undergoing invasive procedures in the context of long-acting factor XI inhibition with abelacimab.
Does long-acting factor XI inhibition with abelacimab reduce or maintain low rates of peri-procedural bleeding compared to rivaroxaban in patients with atrial fibrillation undergoing invasive procedures?
RCT (n=441)
Open-label between abelacimab and rivaroxaban, double-blind for abelacimab doses
1:1:1
Yes
Does long-acting factor XI inhibition with abelacimab reduce or maintain low rates of peri-procedural bleeding compared to rivaroxaban in patients with atrial fibrillation undergoing invasive procedures?
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“You could imagine that if factor XI inhibition is really as safe as it seems to be, particularly with respect to bleeding around procedures, we could change the paradigm of how we manage anticoagulation without needing to interrupt, particularly for some of these lower-bleeding-risk procedures that end up actually being the most common in this patient population.”
“This is important because abelacimab has a half-life of 28 days. It's a long-acting anticoagulant. Whereas with rivaroxaban, the half-life is 6 to 12 hours, so if you interrupt it, you are essentially going into the procedure off the drug. So it is remarkable that the rates of bleeding were comparable across both treatments.”
“These results are encouraging and add to the growing body of evidence supporting the safety profile of abelacimab and suggest that long-acting factor XI inhibition is feasible in a contemporary atrial fibrillation patient population who commonly require invasive procedures. While traditionally the approach for DOACs (and warfarin) has been to interrupt anticoagulation for most elective procedures, these data suggest that such routine interruption may not be necessary with abelacimab for all elective procedures.”
Patients with atrial fibrillation treated with the long-acting factor XI inhibitor abelacimab can undergo invasive procedures with low rates of bleeding comparable to rivaroxaban, suggesting routine interruption of anticoagulation may not be necessary for low-risk procedures.
Background: In AZALEA-TIMI 71, abelacimab, a novel factor XI inhibitor, significantly reduced the rate of major or clinically relevant non-major (CRNM) bleeding compared with rivaroxaban in patients with atrial fibrillation (AF). Abelacimab is long-acting with a half-life of ~28 days. Objective: To examine peri-procedural bleeding among patients undergoing invasive procedures in the context of long-acting factor XI inhibition with abelacimab. Methods: AZALEA-TIMI 71 was designed to assess the bleeding profile of abelacimab relative to rivaroxaban. Patients were randomized to either 1 of 2 abelacimab doses (90 or 150 mg subcutaneously monthly) or to rivaroxaban daily. Invasive procedures occurring during follow-up were categorized as low, intermediate, or high bleeding risk. Peri-procedural bleeding events were identified as major/CRNM bleeds, as adjudicated by a clinical events committee blinded to treatment assignment, occurring within 30 days after a procedure, and related to the procedure on blinded review. Results: A total of 920 procedures occurred in 441 patients, with approximately 1 in 3 patients in both rivaroxaban and abelacimab arms undergoing an invasive procedure over a median follow-up of 2.1 years. Most procedures were low bleeding risk (n=696, 75.7%) and elective (n=686, 74.6%). The median time to a procedure from the last dose of abelacimab was 29 (25th–75th percentile: 20–42) days, with 336 of the 602 (55.8%) procedures in the abelacimab arms occurring within the monthly dosing interval. Overall, the occurrence of peri-procedural major or CRNM bleeding was low (<2% of all procedures), representing 1.2% of all procedures in the abelacimab arms vs. 2.2% of all procedures in the rivaroxaban arm (RR 0.54 [95% CI 0.19–1.58]), with consistent results in the individual abelacimab dosing arms. For procedures occurring within 30 days of an abelacimab dose, major or CRNM bleeds occurred in only 3 of the 336 (0.9%) procedures. Conclusion: These data illustrate that patients with AF treated with abelacimab, a long-acting factor XI inhibitor, can undergo invasive procedures with low rates of bleeding. Moreover, these findings suggest that routine interruption of anticoagulation may not be necessary for all procedures in the context of factor XI inhibition, particularly for procedures which are low bleeding risk.
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Patel et al. (2025) conducted an RCT in Atrial fibrillation (n=441). Abelacimab vs. Rivaroxaban 20 mg daily was evaluated on Peri-procedural major or clinically relevant non-major (CRNM) bleeding within 30 days after a procedure (RR 0.54, 95% CI 0.19-1.58). Abelacimab resulted in a low rate of peri-procedural major or clinically relevant non-major bleeding (1.2%) compared to rivaroxaban (2.2%) in patients with atrial fibrillation undergoing procedures.
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