PB0523 - Interim results from a non-interventional, post authorisation safety study of nonacog beta pegol as routine prophylaxis in patients with haemophilia B

Background: Ongoing global post-authorisation safety study (requested by the European Medicines Agency, sponsored by Novo Nordisk) interim analysis, investigating nonacog beta pegol (N9-GP) prophylaxis in patients with haemophilia B.

Aims: Evaluate the safety and efficacy of N9-GP prescribed by physicians in routine practice.

Methods: International, multi-centre study aiming to enroll 60 any-age males with haemophilia B who received N9-GP prophylaxis at physicians’ discretion. Study approved by independent ethics committee. Informed consent obtained. Patients with N9-GP hypersensitivity and pre existing factor IX (FIX) inhibitors excluded. First visit: 01/04/2019; last visit expected: Q4 2027. Primary endpoint: adverse drug reaction (ADR) occurrence; additional endpoints: serious adverse event (SAE) frequency, bleed count, haemostatic effect, polyethylene glycol (PEG) plasma levels, neurological examinations.

Results: At interim cut-off (31/03/2022), 41 patients were enrolled; mean (range) age: 34 years (9–74); disease severities: 2% mild, 27% moderate, 66% severe, 5% missing. Four patients withdrew (one withdrawal of consent; three on physician decision [one moved from centre, two due to bleedings]). Cumulative N9 GP exposure time: 40 patient-years. During a median (range) treatment period of 1.1 years (0–2.4), no ADRs, allergic reactions, thromboembolic events or FIX inhibitors were reported. Six patients reported AEs (Table 1). Two SAEs (gastric ulcer, cholecystitis) and one AE of special interest (headache) were reported. No AEs were considered treatment-related. Mean (median) annualised bleeding rate was 0.49 bleeds/year (0.00); 73% of patients reported no bleeds (Table 2). No bleeds resulted in re-bleeds. Although mean PEG plasma levels were stable, three patients had levels ≥8.0 μg/mL: two attributed to higher/more frequent dosing, one to high body weight. Of the four patients with abnormal neurological examination findings at baseline, one experienced symptomatic deterioration (abnormal gait) attributed to ankle complications.

Conclusion(s): In real-world practice, N9-GP prophylaxis in patients with haemophilia B was efficacious, with no safety concerns identified. These findings confirm clinical trial observations.