939-19 - BLEEDING WITH THE FXI INHIBITOR ABELACIMAB COMPARED WITH RIVAROXABAN IN OLDER INDIVIDUALS WITH ATRIAL FIBRILLATION: ANALYSIS OF THE AZALEA-TIMI 71 TRIAL

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Author Block: Samer Al Said, Siddharth M. Patel, Robert P. Giugliano, David A. Morrow, Erica L. Goodrich, Sabina A. Murphy, Bruce Hug, Sanobar Parkar, Shih Ann Chen, Shaun G. Goodman, Boyoung Joung, Robert Gabor Kiss, Jindrich Spinar, Wojciech Wojakowski, Jeffrey I. Weitz, Daniel M. Bloomfield, Marc Steven Sabatine, Christian T. Ruff, TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital and, Boston, MA, USA
Background: Age is a known risk factor for anticoagulant-related bleeding. In AZALEA-TIMI 71, the novel factor XI inhibitor abelacimab reduced the risk of bleeding compared with rivaroxaban (RIVA) in pts with atrial fibrillation (AF). In this analysis, we examined the safety of abelacimab vs. RIVA by age.
Methods: AZALEA-TIMI 71 randomized 1,287 pts with AF to 1 of 2 abelacimab doses (90 or 150 mg monthly) or RIVA (20/15mg daily) with median f/u of 2.1 yrs. Cox proportional hazards were used to examine the primary outcome of major/clinically relevant non-major (CRNM) bleeding with an interaction term for treatment*age (≥75 vs <75 yrs).
Results: Of 1,287 pts, 625 (49%) were ≥75 yrs at baseline. Pts ≥75 had lower BMI (28 vs. 32 kg/m2) and were less likely to be on antiplatelet therapy (17% vs. 32%) but more likely to have CrCl ≤50 mL/min (33% vs. 8%) compared with younger pts (p<0.001 for each). Compared with RIVA, both doses of abelacimab significantly reduced the risk of major/CRNM bleeding irrespective of age (Fig). Pts ≥75 yrs had greater absolute risk reduction in bleeding from abelacimab (ARR of 7.1% and 6.2% for abelacimab 90 and 150 mg vs. RIVA) than those <75yrs (4.7% and 4.2% for both doses respectively) (Fig).
Conclusion: Inhibition of FXI with abelacimab significantly reduced the relative risk of bleeding compared with RIVA regardless of age, with potential for greater absolute reductions in those age ≥75 y. These data suggest that FXI inhibitor may be especially beneficial in minimizing bleeding in older pts with AF.