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.

MATERIALS AND METHODS: Male patients, ≤65 years old with severe haemophilia B (FIX activity ≤2%) requiring non-emergency surgery were enrolled in the surgical substudy of PROLONG-9FP. Dosing was based on World Federation of Hemophilia guidelines and patients' pharmacokinetics. Haemostatic efficacy was assessed on a 4-point scale. rIX-FP consumption and safety were monitored throughout the perioperative period.

RESULTS: This updated dataset reports on thirty (8 minor and 22 major) surgeries conducted in 21 patients. A single preoperative bolus was used in 96.7% (n = 29) of surgeries. After minor surgery, patients received a median (range) of 0 (0-3) infusions with a median (range) consumption of 0 (0-178.89) IU/kg in the 14-day postoperative period. In patients who underwent major surgery (including 15 patients undergoing joint replacement surgery), the median (range) number of infusions in the 14-day postoperative period was 5 (0-11) and median consumption was 221.7 (0-444.07) IU/kg. Haemostatic efficacy was rated as excellent or good in 87.5% (7/8) of minor surgeries and 95.5% (21/22) of major surgeries.

METHODS: Patients chose to continue treatment with nonacog beta pegol in either one of two once-weekly prophylaxis arms (10IU/kg or 40IU/kg), or an on-demand arm (40IU/kg for mild/moderate bleeds; 80IU/kg for severe bleeds). The primary objective was to evaluate immunogenicity; key secondary objectives included assessing safety and haemostatic efficacy in the treatment and prevention of bleeds.

RESULTS: Seventy-one patients received prophylaxis or on-demand treatment. No patient developed an inhibitor and no safety concerns were identified. The success rate for the treatment of reported bleeds was 94.6%; most (87.9%) resolved with one injection. The median annualised bleeding rate for patients on prophylaxis was 1.36 (interquartile range [IQR] 0.00-2.23) and 1.00 (IQR 0.00-2.03) for the 10 and 40IU/kg treatment arms, respectively. The mean FIX activity trough achieved for 10 and 40IU once weekly was 9.8% and 21.3%, respectively. Fourteen patients on prophylaxis underwent 23 minor surgical procedures; haemostatic perioperative outcomes for all of those evaluated were 'excellent' or 'good'.