930-09 - FACTOR XI INHIBITION WITH ABELACIMAB IN ATRIAL FIBRILLATION ACROSS THE SPECTRUM OF BLEEDING RISK

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Author Block: Siddharth M. Patel, Robert P. Giugliano, David A. Morrow, Erica L. Goodrich, Bruce Hug, Sanobar Parkar, Shih Ann Chen, Shaun G. Goodman, Boyoung Joung, Robert Gabor Kiss, Jindrich Spinar, Wojciech Wojakowski, JR, Jeffrey I. Weitz, Daniel M. Bloomfield, Marc Steven Sabatine, Christian Thomas Ruff, Brigham and Women's Hospital, Boston, MA, USA
Background: In AZALEA-TIMI 71, the novel factor XI inhibitor abelacimab significantly reduced the risk of major/CRNM bleeding vs. rivaroxaban in pts with atrial fibrillation (AF). We examined the safety of abelacimab vs. rivaroxaban by bleeding risk.
Methods: AZALEA-TIMI 71 randomized 1,287 pts with AF, with median f/u of 2.1 years. Abelacimab doses (90 & 150 mg SC monthly) were pooled for this analysis. Bleeding risk was categorized using the previously validated DOAC score (Fig).
Results: Overall, 8%, 33%, 37%, 16% and 5% of pts were categorized as very low (score 0-3), low (4-5), moderate (6-7), high (8-9) and very high (10) bleeding risk. In the rivaroxaban arm, rates of major/CRNM bleeding increased stepwise with higher DOAC scores (2.5% to 21.2% per 100 PY across categories), whereas the absolute magnitude of this gradient was attenuated in the abelacimab arm (0.7% to 7.1% per 100 PY; Fig). The relative reduction in the risk of major/CRNM bleeding with abelacimab vs. rivaroxaban was consistent regardless of bleeding risk (p-trend for HRs across categories = 0.48), whereas the absolute risk reductions grew for pts at higher bleeding risk (ARR 1.7% to 14.1% per 100 PY for very low to very high bleeding risk; p-trend <0.0001; Fig).
Conclusion: Abelacimab reduces bleeding vs. rivaroxaban across the spectrum of bleeding risk, with greater absolute reductions in those at high bleeding risk. Emerging factor XI inhibitor therapies may be especially attractive in pts with AF at high bleeding risk.