The new factor XI inhibitor shows superior safety in the treatment of atrial fibrillation

The new factor XI inhibitor shows superior safety in the treatment of atrial fibrillation

Patients with atrial fibrillation are typically prescribed an anticoagulant or blood thinner to reduce the risk of stroke, but many may stop taking it or never receive a prescription because of the risk of increased risk of bleeding complications. Brigham General researchers evaluated a drug that represents a new class of anticoagulants known as factor XI inhibitors to treat patients with atrial fibrillation as part of the Azalea-Timi 71 trial. The study was stopped early by the recommendation of the Data Monitoring Committee due to an overwhelming reduction in bleeding compared to standard care treatment. The researchers report in theNew England Journal of Medicine This abelacimab, a factor XI inhibitor, significantly reduced bleeding compared to an anticoagulant rivaroxaban.

“It should be tremendously satisfying to the cardiovascular community, patients and providers, that the factor “Atrial fibrillation is a common disease, and bleeding with currently available anticoagulants resulting in significant undertreatment is still one of the major shortcomings in cardiovascular disease.”

About 1 in 3 people develop atrial fibrillation, making it one of the most common cardiovascular conditions in the world. The risk of stroke increases significantly in patients with atrial fibrillation because blood clots can form in the heart chambers and be pumped to the brain, leading to a stroke.

The Azalea-Timi 71 trial is the largest and longest trial evaluating a factor XI inhibitor versus standard of care, direct oral anticoagulants. The team included 1,287 participants at 95 study locations worldwide. Participants were randomized to receive monthly injections of 150 mg abelacimab, 90 mg abelacimab, or a standard dosage of rivaroxaban (20 mg or 15 mg in dose-reduced patients). The team found that the 150 mg dose of abelacimab reduced bleeding or requiring medical attention by 62% compared to rivaroxaban. The 90 mg dose of abelacimab reduced the same bleeding by 69%. Additionally, the team found that both doses of abelacimab nearly eliminated compared with rivaroxaban, which is the most common type of bleeding seen in patients on currently available anticoagulants.

The team notes that in the Azalea-Timi 71 trial, stroke rates were low and there were no significant differences between patients in the abelacimab groups compared to patients taking rivaroxaban, even though the trial was not powered for ischemic events.

The Timi Study Group is leading an ongoing Phase 3 study of the trial, Lilac-Timi 76, that will compare the 150 mg dose abelacimab with high-risk atrial fibrillation to high-risk patients identified as not approved for current anticoagulant for the prevention of ischemic stroke and systemic embolism.

The Azalea-Timi 71 study validated that factor XI inhibitors have an incredibly safe bleeding profile in patients with atrial fibrillation, which is a huge potential advance for our patients. Now we can shift our attention as we wait for the results of the Phase 3 trials. “

Christian Ruff, MD, MPH, Director of General Cardiology within the Cardiovascular Division, Brigham and Women's Hospital

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