ABSTRACT NUMBER: ESOC2026LB198 BLOOD PRESSURE AND RESPONSE TO ANDEXANET IN FXA INHIBITOR-ASSOCIATED INTRACRANIAL HEMORRHAGE – SECONDARY ANALYSES OF ANNEXA-I

Abstract Background and aims Elevated blood pressure (BP) is a significant predictor of hematoma expansion (HE) and may interact with hemostatic therapies intended to limit hematoma growth. We investigated the association between baseline and post-randomization BP and outcomes in patients with acute FXa inhibitor–associated intracerebral hemorrhage (ICH), and whether BP modified the treatment effect of andexanet in the ANNEXa-I trial. Methods We conducted secondary analyses of ANNEXa-I participants stratified by quartiles of systolic BP (SBP) and diastolic BP (DBP) at baseline and at 3-, 6-, and 12-hours post-randomization. We assessed treatment interactions across these BP strata for effective hemostasis, HE, and acute neurological deterioration at 12 hours; avoidance of rescue therapy between 3 and 12 hours; mortality at 12 hours and 30 days; and good functional outcome (modified Rankin Scale 0–3) at 30 days. Results Among 530 participants with FXa inhibitor–associated ICH enrolled in the trial, the mean (standard deviation) baseline SBP and DBP were 158.5 (26.4) and 84.6 (18.1) mm Hg, respectively. Patients with HE had higher mean baseline DBP compared to patients without HE (88.1[19.0] vs. 83.1[17.4] mm Hg, p=0.004). No treatment interactions were observed between baseline SBP or DBP and the primary endpoint of effective hemostasis, nor with any pre-specified secondary endpoints. Analyses of subgroup interactions according to post-randomization BP are ongoing and will be presented. Conclusions These secondary analyses of the ANNEXa-I trial, examining baseline and post-randomization BP, will inform individualized clinical decision-making for patients with acute FXa inhibitor–associated intracerebral hemorrhage. Conflict of interest