ABSTRACT NUMBER: ESOC2026A1929 HAEMATOMA EXPANSION AND THROMBOTIC EVENTS IN PATIENTS WITH FACTOR XA-INHIBITOR ASSOCIATED INTRACEREBRAL HEMORRHAGE—INTERIM ANALYSIS OF FIRE-XA

Abstract Background and aims Intracerebral hemorrhage (ICH) associated with recent factor Xa inhibitor (FXaI) intake warrants reversal therapy to prevent haematoma expansion but may increase the risk of thrombotic events (TE). We thought to provide a contemporary update on the use of reversal agents and early TEs. Methods This is an interim-analysis of FIRE-Xa (NCT06383741), a prospective, international multi-centre study enrolling consecutive patients with FXaI-associated ICH from 11 sites in Switzerland and Germany. Primary outcome for this analysis is use of reversal agents (Andexanet alfa = AA, prothrombin complex concentrate = PCC or no reversal) and TE (assessed up hospital discharge). Results By December 1, 2025, we enrolled 98 patients in FIRE-Xa. The median age was 81 years (IQR 76-85), 42% were female, the NIHSS at admission was 9 (IQR 3-14), median drug-specific anti-Xa activity was 124 ng/ml (IQR 68-217) and the median duration of hospitalization was 9 days (IQR 6-14). Among 62 patients (63%) receiving any haemostatic therapy, 28 patients received AA and 36 patients received PCC (2 patients received both). Overall, 6 TEs occurred (4 ischaemic stroke: 1 no reversal, 1 AA, 2 PCC), 2 systemic embolism: 1 no reversal, 1 PCC). No patient had myocardial infarction or deep venous thrombosis. Conclusions This study provides real-world data on the contemporary use of reversal agents in patients with FXaI-associated ICH and early TE. Conflict of interest Janis Rauch: nothing to disclose.