BARCELONA — Researchers here showed overall enthusiasm for factor XIa inhibitors, which have been shown to keep bleeding at bay when added to standard dual antiplatelet therapy, though there were only hints of efficacy in preventing ischemic events that emerged in preliminary trials presented at the European Society of Cardiology Congress.
PACIFIC AMI
In this phase II study, which was published simultaneously in Circulation, three doses of the novel factor XIa inhibitor asundexian — 10 mg, 20 mg, and 50 mg daily — reduced factor XIa activity in a dose-dependent manner by up to more than 90% in patients with recent acute MI, without significantly increasing bleeding, reported John Alexander, MD, MHS, of Duke University in Durham, North Carolina.
Among 1,600 patients who also received dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor, the prespecified main safety outcome — Bleeding Academic Research Consortium type 2, 3, or 5 bleeding — occurred in 7.6% of patients receiving asundexian 10 mg, 8.1% of those receiving 20 mg, 10.5% of those receiving 50 mg, and 9.0% of those receiving placebo over a median follow-up of 368 days (pooled asundexian vs placebo: HR 0.98, 90% CI 0.71-1.35).
The primary efficacy outcome — a composite of cardiovascular death, MI, stroke, or stent thrombosis — occurred in 6.8%, 6.0%, 5.5%, and 5.5% of patients, respectively (pooled asundexian 20 and 50 mg vs placebo: HR 1.05, 90% CI 0.69-1.61).
At an ESC press conference, Alexander said bleeding episodes with asundexian at all doses — including 50 mg — were not statistically different than those seen in patients on dual antiplatelet therapy plus placebo. However, he also noted that there was no reduction in ischemic events with asundexian compared with placebo.
He suggested that the lack of efficacy might be due to the small numbers of events in the trial overall. “These results, together with existing genetic and preclinical evidence, suggest the further study of the factor XIa inhibitor asundexian in adequately-sized phase III studies as a potentially safer anticoagulant for patients following an acute myocardial infarction.”
In an accompanying editorial, Gregory Lip, MD, of the University of Liverpool in England, and colleagues wrote, “Despite revascularization and optimal secondary prevention, including dual antiplatelet medication, patients with acute coronary syndrome remain at risk of recurrent ischemic events, with up to 7% risk of recurrent myocardial infarction at 3 years.”
“To address this residual risk, prior studies have investigated the benefit of increasing the intensity of antithrombotic medication, through the addition of an oral anticoagulant … to antiplatelet therapy,” he continued. “While studies have generally shown a significant reduction in ischemic events with this approach, it came at a significant cost of excess major hemorrhage.”
“The phase II study is important,” Lip added, “showing the apparent safety of asundexia