Long‐term immunogenicity, efficacy and tolerability of simoctocog alfa in patients with severe haemophilia A who had completed the NuProtect study in previously untreated patients

Abstract

Background The NuProtect study reported data on the immunogenicity, efficacy and tolerability of simoctocog alfa (Nuwiq®) in 108 previously untreated patients with severe haemophilia A planned to be treated for ≥100 exposure days or up to 5 years. The NuProtect‐Extension study collected long‐term prophylaxis data in children with severe haemophilia A. Methods Patients who completed the NuProtect study according to the protocol were eligible for the NuProtect‐Extension study, a prospective, multinational, non‐controlled, Phase 3b study. Results Of 48 patients who entered the extension study, 47 (median age 2.8 years) received prophylaxis with simoctocog alfa for a median of 24 months, with 82%–88% on a twice‐weekly or less regimen. No patient developed FVIII inhibitors during the extension study. The median (IQR) annualized bleeding rate (ABR) during prophylaxis was 0 (0–0.5) for spontaneous bleeding episodes (BEs) and 1.00 (0–1.95) for all BEs. ABRs estimated using a negative binomial model were .28 (95% CI: .15, .53) for spontaneous and 1.62 (95% CI: 1.09, 2.42) for all BEs. During the median follow‐up of 24 months, 34 (72%) patients had zero spontaneous BEs and 46 (98%) had zero spontaneous joint BEs. Efficacy in treating BEs was excellent or good for 78.2% of rated BEs, and efficacy of surgical prophylaxis was excellent for two rated surgeries. No treatment‐related adverse events were reported. Conclusion No FVIII inhibitors developed during long‐term prophylaxis in the NuProtect‐Extension study. Prophylaxis with simoctocog alfa was efficacious and well‐tolerated, and is therefore an attractive long‐term option for children with severe haemophilia A.