ABSTRACT NUMBER: ESOC2026A1268 PATIENTS WITH LARGER INFARCT CORES RANDOMIZED TO ARG-007 HAD BETTER FUNCTIONAL OUTCOMES: RESULTS FROM THE PHASE II ARG-007-002 SEANCON TRIAL

Abstract Background and aims SEANCON was a multicentre, randomised, double-blind, Phase II trial evaluating ARG-007 (R18D), a cationic poly-arginine peptide in patients with acute ischaemic stroke (AIS) undergoing endovascular thrombectomy (EVT). Primary analyses demonstrated the safety and tolerability of ARG-007. In this post-hoc sub-analysis, AI imaging biomarkers were used to explore efficacy and optimum target population of ARG-007. Methods Participants were randomised 1:1 to receive ARG-007 (0.3 mg/kg IV over 10 minutes) or placebo prior to completion of revascularisation. Baseline standard-of-care imaging was analysed using AI core lab software (Brainomix, Oxford, UK). Automated outputs were reviewed for accuracy by expert clinicians blinded to treatment allocation. Results 90 of the 93 patients randomised had analysable baseline imaging scans. There was a chance imbalance in baseline imaging characteristics: patients subsequently treated with ARG-007 showed a trend for larger baseline ischemic cores and more severe ischemic injury (greater net-water-uptake) prior to randomisation. Multivariate regression modelling showed a significant interaction effect between baseline infarct core extent and treatment arm. Compared to placebo, patients with larger baseline ischemic cores (lower eASPECTS, larger acute ischaemic volumes) treated with ARG-007 had lower 24h-NIHSS (OR -0.37,CI: -0.66- -0.09, p=0.011) and better 3-month functional outcome (mRS, OR 2.68, CI:1.01-7.25, p=0.046). Conclusions In AIS patients undergoing EVT, ARG-007 administered within 24 hours of stroke onset significantly reduced the likelihood of a poor functional outcome in patients with larger baseline infarct cores. ARG-007 is a promising adjunct treatment for medium-large core patients undergoing recanalization treatment. Conflict of interest Davide Carone: Employee of Brainomix, salary and share options; George Harston: Employee of Brainomix, salary and share options. David Blacker: shareholder in Argenica Therapeutics Ltd and is paid a consultancy fee as Chair of the Argenica Clinical Advisory Committee. Meghan Thomas: Employee at Argenica Therapeutics Figure 1 - belongs to Results