AIM: This is a planned interim analysis of pathfinder™3, an international, open-label, Phase 3 trial evaluating the efficacy and safety (including immunogenicity) of N8-GP administered before, during and after major surgery in severe haemophilia A patients aged ≥12 years.

METHODS: Sixteen patients who underwent 18 major surgical procedures (including synovectomy, joint replacement and ankle arthrodesis) were included here. Postoperative assessments were conducted daily for days 1-6, and once for days 7-14. Primary endpoint was N8-GP haemostatic efficacy, assessed after completion of surgery using a four-point scale ('excellent', 'good', 'moderate', 'none').

RESULTS: Haemostasis was successful (rated 'excellent' or 'good') on completion of surgery in 17 (94.4%) procedures and rated as 'moderate' (5.6%) for one surgery in a patient with multiple comorbidities who needed an intraoperative N8-GP dose (20.7 IU kg-1 ). In the postoperative period, three bleeds occurred (one during days 1-6; two during days 7-14); all were successfully treated with N8-GP. Mean N8-GP consumption on day of surgery was 80.0 IU kg-1 ; patients received a mean of 1.7 doses (median: 2, range: 1-3). No safety concerns were identified.