Abstract Number: Esoc2026lb158 Lb158 - Net Benefit and Time Course of Benefit of Asundexian for Secondary Stroke Prevention in the Oceanic-Stroke Randomised, Placebo-Controlled Clinical Trial

Abstract Background and aims Asundexian 50 mg once daily added to antiplatelet therapy reduced the occurrence of ischaemic stroke (IS) compared with placebo (cause-specific hazard ratio csHR 0.74; 95% confidence interval CI: 0.65–0.84). We sought to characterise the time course of benefit and describe the prespecified net benefit outcomes. Methods We randomised 12,327 participants within 72 h of acute IS or high-risk transient ischaemic attack (TIA) to asundexian or placebo. csHRs were derived from a stratified Cox proportional hazards model. HRs over time were calculated. A restricted cubic spline was generated to display the relationship between HR and time for the primary outcome of IS. Results The risk of the composite outcome of IS or International Society on Thrombosis and Haemostasis (ISTH) major bleeding was lower with asundexian than with placebo (430 7.0% vs 529 8.6%; csHR, 0.82; 95% CI: 0.72–0.93). Similar reductions were seen for the composite outcome of cardiovascular death, all stroke, myocardial infarction or ISTH major bleeding (518 8.5% vs 611 10.0%; csHR, 0.85; 95% CI: 0.76–0.96) and the composite outcome of all-cause mortality, disabling stroke, fatal bleeding or symptomatic intracranial haemorrhage (189 3.1% vs 234 3.8%; csHR, 0.81; 95% CI: 0.67–0.99). HRs over time are shown in the table. The initial csHR for IS was 0.84 (95% CI: 0.69–1.02) and decreased over time. Cubic splines will be presented. Conclusions Asundexian added to antiplatelet therapy after non-cardioembolic IS or high-risk TIA reduces the occurrence of IS, with benefit consistent through the treatment period. Net benefit outcomes favour asundexian. Conflict of interest Table 1 - belongs to Conclusions