Fewer Bleeding Events Seen With Abelacimab Than Rivaroxaban in A-Fib

THURSDAY, Jan. 23, 2025 (HealthDay News) — Subcutaneous injection of abelacimab results in lower levels of free factor XI and significantly fewer bleeding events than rivaroxaban in patients with atrial fibrillation at moderate-to-high risk for stroke, according to a study published in the Jan. 23 issue of the New England Journal of Medicine.

Christian T. Ruff, M.D., M.P.H., from Brigham and Women”s Hospital in Boston, and colleagues randomly assigned 1,287 patients with atrial fibrillation and a moderate-to-high risk for stroke to receive subcutaneous injection of abelacimab (150 mg or 90 mg once monthly) administered in a blinded fashion or oral rivaroxaban (20 mg once daily) administered in an open-label fashion in a 1:1:1 ratio. The primary end point was major or clinically relevant nonmajor bleeding.

The researchers found that the median reduction in free factor XI levels was 99 and 97 percent with abelacimab at a dose of 150 and 90 mg, respectively, at three months. Based on the recommendation of the independent data monitoring committee, the trial was stopped early due to a greater-than-anticipated reduction in bleeding events with abelacimab. The incidence rate of major or clinically relevant nonmajor bleeding was 3.2, 2.6, and 8.4 events per 100 person-years with 150 mg abelacimab, 90 mg abelacimab, and rivaroxaban, respectively (hazard ratios, 0.38 and 0.31 for 150 mg abelacimab versus rivaroxaban and 90 mg abelacimab versus rivaroxaban, respectively). The three groups had a similar incidence and severity of adverse events.

“We showed a lower incidence of major and clinically relevant nonmajor bleeding, as well as a lower incidence of major bleeding and any bleeding event, with abelacimab as compared with rivaroxaban,” the authors write.

The study was funded by Anthos Therapeutics, which manufactures abelacimab.

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