ABSTRACT NUMBER: ESOC2026LB57 LB57 - THE PREDICTIVE VALUE OF BASELINE CT HYPODENSITY AND SPOT SIGN ON CT ANGIOGRAPHY IN THE FASTEST TRIAL

Abstract Background and aims We report the pre-specified subgroup analysis of the rFVIIa for Acute Hemorrhagic Stroke at Earliest Time Trial (FASTEST) of patients with a CT hypodensity sign focusing on hematoma expansion and response to treatment. Methods In a prespecified analysis, we assessed the hypodensity sign as a treatment effect modifier of intravenous rFVIIa in the phase 3, multi-national, double-blind, adaptive randomized FASTEST trial. Baseline and 24-hour CTs were obtained, with CTA available in 82%; all imaging was centrally read by a blinded neuroradiologist. Effect modification was assessed for the trial’s primary outcome of 180-day disability (ordinal modified Rankin score 0-2, 3, 4-6) and, secondarily, for 24-hour growth of intracranial hemorrhage. As per the trial’s primary analysis, ordinal logistic regression was adjusted by age, baseline ICH and IVH volumes, and pre-ICH modified-Rankin-Score (mRS). Results Of 626 participants, 328 (52%) had a hypodensity sign on baseline CT. The hypodensity sign was associated with higher mean baseline ICH volumes (23.12ml, SD15.79) than those without (9.59ml, SD8.67). The hypodensity sign didn’t show evidence of interaction on the 180-day mRS (OR 1.142, 95%CI: 0.726-1.797) but did for 24-hour growth of ICH (-4.871ml, 95%CI: -7.580, -2.162). rFVIIa’s impact on hemorrhage growth and treatment effect was greatest in those with both a spot-sign and hypodensity. Conclusions Hypodense sign did not modify the clinical treatment effect of FVIIa. Having both hypodensity and spot signs at baseline was the strongest predictor of the impact of rFVIIa on reducing expansion of ICH+IVH and improving functional outcome. Conflict of interest Table 1 - belongs to Results Table 2 - belongs to Results