Nonacog Beta Pegol (N9-GP) in Bleeding Prophylaxis in Patients with Hemophilia B – Real World Data

Study Methodology and Observed Population

A total of 42 patients with hemophilia B aged 7–72 years (average age 42 years), who had been using nonacog beta pegol for ≥ 6 months as bleeding prophylaxis, were included in the retrospective multicenter study from the Canadian Bleeding Disorders Registry (CBDR) as of March 31, 2021. Before switching to the new drug, they had been receiving another preparation for at least 6 months - either recombinant factor IX/fusion protein (rFIXFc; 62%) or recombinant factor IX with a standard biological half-life (SHL rFIX; 38%). Severe hemophilia was present in 62%, moderate in 36%, and mild in 2% of patients. The parameters observed were treatment efficacy, specifically the incidence of bleeding, and the consumption of coagulation factor IX.

Results

The total observation period was 148.0 patient-years. During the prophylactic treatment with N9-GP lasting an average of 2.3 years, a total of 232 bleeding events were reported in 30 patients (71%). Joint bleeding occurred in 186 cases (80%) in 26 patients. The median overall annual bleeding rate with N9-GP treatment was 2.1 (compared to 6.6 with SHL rFIX treatment) and 0.73 (compared to 1.44 with previous rFIXFc treatment). This reduction in bleeding incidence was statistically significant in patients transitioning from SHL rFIX to N9-GP (relative risk [RR] 0.5; 95% confidence interval [CI] 0.27–0.94; p = 0.03), unlike the transition from rFIXFc (RR 0.63; 95% CI 0.37–1.07; p = 0.09).

The average consumption of factor IX was lower in patients using N9-GP compared to previous treatment with SHL rFIX (2152 vs. 3018 IU/kg) and rFIXFc (1766 vs. 2278 IU/kg). The annual infusion frequency was 50.5 after transitioning from SHL rFIX (compared to 57.6) and 39.2 after transitioning from rFIXFc (compared to 51.0). In 90.2% of patients using N9-GP after previous SHL rFIX treatment, 1 infusion was sufficient to stop the bleeding; previously, this was sufficient in only 73.2% of patients.

No adverse events were reported during N9-GP treatment.

Conclusion

The switch to nonacog beta pegol seems appropriate for more effective bleeding control with lower consumption of coagulation factor IX in patients with hemophilia B, regardless of previous replacement therapy.

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Source: Matino D., Iorio A., Keepanasseril A. et al. Switching to nonacog beta pegol in hemophilia B: outcomes from Canadian real-world, multicenter, retrospective study. Res Pract Thromb Haemost2022 Mar 31; 6 (3): e12661, doi: 10.1002/rth2.12661.