Skip to content 
The Pacific AF trial was published in The Lancet in April 2022. It was a phase 2 randomized controlled trial performed at multiple centers in 14 countries including European, Canada, and Japan. The study compared the novel oral small molecule activated coagulation factor XIa (FXIa) inhibitor asundexian to apixaban in patients 45 years or older with atrial fibrillation.
755 patients were randomly assigned to treatment. Two patients (assigned to asundexian 20 mg) never took any study medication, resulting in 753 patients being included in the analysis (249 received asundexian 20 mg, 254 received asundexian 50 g, and 250 received apixaban). The mean age of participants was 73·7 years (SD 8·3), 309 (41%) were women, 216 (29%) had chronic kidney disease, and the mean CHA2DS2-VASc score was 3·9 (1·3). Asundexian 20 mg resulted in 81% inhibition of FXIa activity at trough concentrations and 90% inhibition at peak concentrations; asundexian 50 mg resulted in 92% inhibition at trough concentrations and 94% inhibition at peak concentrations. Ratios of incidence proportions for the primary endpoint were 0·50 (90% CI 0·14–1·68) for asundexian 20 mg (three events), 0·16 (0·01–0·99) for asundexian 50 mg (one event), and 0·33 (0·09–0·97) for pooled asundexian (four events) versus apixaban (six events). The rate of any adverse event occurring was similar in the three treatment groups: 118 (47%) with asundexian 20 mg, 120 (47%) with asundexian 50 mg, and 122 (49%) with apixaban.
Therefore, the FXIa inhibitor asundexian at doses of 20 mg and 50 mg once daily resulted in lower rates of bleeding compared with standard dosing of apixaban, with near-complete in-vivo FXIa inhibition, in patients with atrial fibrillation. Asundexian may become a safer option for patients with atrial fibrillation improving the risk of bleeding. The clinical efficacy of asundexian as an anticoagulant still needs to be investigated. The Oceanic AF phase 3 trial is ongoing until 2025 and it could help answer this question.
Reference:
