Jonathan P. Piccini, MD, Associate Professor at Duke University. In this video, he speaks about the Safety of the oral factor XIa inhibitor asundexian compared with apixaban in patients with atrial fibrillation (PACIFIC-AF): a multicentre, randomised, double-blind, double-dummy, dose-finding phase 2 study.
The use of direct-acting oral anticoagulants for stroke prevention in atrial fibrillation is restricted due to bleeding concerns. Asundexian, a new oral small molecule activated coagulation factor XIa (FXIa) inhibitor, has the potential to minimize thrombosis while having no effect on haemostasis. In individuals with atrial fibrillation, we wanted to find the best dose of asundexian and compare the risk of bleeding to that of apixaban.
We compared asundexian 20 mg or 50 mg once daily with apixaban 5 mg twice daily in patients 45 years or older with atrial fibrillation, a CHA2DS2-VASc score of at least 2 if male or at least 3 if female, and an increased bleeding risk in this randomised, double-blind, phase 2 dose-finding study. The research was carried out at 93 sites across 14 nations, including 12 in Europe, Canada, and Japan. Using an interactive web response system, participants were randomly assigned (1:1:1) to a treatment group, with randomization stratified by whether patients were using a direct-acting oral anticoagulant prior to the study's start. A double-dummy design was used to achieve masking, with participants receiving both the assigned treatment and a placebo that mimicked the non-assigned therapy. The primary outcome was a composite of major or clinically relevant non-major bleeding based on International Society of Thrombosis and Haemostasis criteria, which was examined in all patients who received at least one dose of study medication. This study is listed on ClinicalTrials.gov as NCT04218266 and EudraCT as 2019-002365-35.
862 patients were registered between January 30, 2020, and June 21, 2021. 755 individuals were randomized to treatment at random. Because two participants (assigned to asundexian 20 mg) did not take any trial medicine, 753 patients were included in the analysis (249 received asundexian 20 mg, 254 received asundexian 50 g, and 250 received apixaban). The participants' mean age was 737 years (SD 83), 309 (41%) were women, 216 (29%) had chronic renal disease, and the mean CHA2DS2-VASc score was 39 (13%). Asundexian 20 mg inhibited FXIa activity by 81 percent at trough concentrations and 90 percent at peak concentrations; asundexian 50 mg inhibited FXIa activity by 92 percent at trough concentrations and 94 percent at peak concentrations. The incidence proportions for the primary endpoint were 050 (90 percent confidence interval 014–168) for asundexian 20 mg (three events), 016 (001–099) for asundexian 50 mg (one event), and 033 (009–097) for pooled asundexian (four occurrences) against apixaban (six events). Any adverse event occurred at the same rate in all three treatment groups: 118 (47%) with asundexian 20 mg, 120 (47%) with asundexian 50 mg, and 122 (49%) with apixaban.
In patients with atrial fibrillation, the FXIa inhibitor asundexian at dosages of 20 mg and 50 mg once daily led in decreased rates of bleeding compared to normal apixaban treatment, with near-complete in vivo FXIa suppression.