AIM: The aim of this study was to evaluate the pharmacokinetics (PK) of N9-GP.
METHODS: Data from 41 previously treated haemophilia B patients, enrolled globally (16 adolescents/adults and 25 children; FIX activity ≤0.02 IU mL-1) with no history of FIX inhibitors, were included. N9-GP was administered once-weekly as 10 IU kg-1or 40 IU kg-1in adolescents/adults and 40 IU kg-1in children. Blood was sampled up to 168 h (1 week) post dose. Standard PK was estimated on the basis of plasma FIX activity vs. time (PK profiles) using non-compartmental methods. Furthermore, a population PK analysis and FIX activity predictions were performed.
RESULTS: Incremental recoveries were 0.02 (IU mL-1)/(IU kg-1) in both adolescents/adults and children. The extended half-life resulted in mean trough levels of 0.27 IU mL-1for adolescents/adults and 0.17 IU mL-1for children at steady-state after weekly dosing at 40 IU kg-1. The population PK analysis confirmed a mono-exponential decay in FIX activity and allowed for predictions of FIX activity for adolescents/adults above 0.15 IU mL-1at all times and 6.4 days week-1in children.
CONCLUSION: N9-GP has the potential to shift previously treated haemophilia B patients from a severe/moderate disease state into a mild- or non-haemophilic range for most of the dosing interval, which is expected to reduce the number of bleeding episodes.
SUMMARY: Background Nonacog beta pegol is a recombinant glycoPEGylated factor IX with an extended half-life, developed to improve care for patients with hemophilia B. Objectives To investigate the safety, efficacy and pharmacokinetics of nonacog beta pegol for the prophylaxis and treatment of bleeds in previously treated children with hemophilia B. Patients/Methods This phase 3 trial, paradigm(™) 5, enrolled and treated 25 children (aged ≤ 12 years) with hemophilia B (FIX ≤ 2%). Patients were stratified by age (0-6 years and 7-12 years), and received once-weekly prophylaxis with 40 IU kg(-1) nonacog beta pegol for 50 exposure days. Results No patient developed inhibitors, and no safety concerns were identified. Forty-two bleeds in 15 patients were reported to have been treated; the overall success rate was 92.9%, and most bleeds (85.7%) resolved after one dose. The median annualized bleeding rates (ABRs; bleeds per patient per year) were 1.0 in the total population, 0.0 in the 0-6-year group, and 2.0 in the 7-12-year group; the estimated mean ABRs were 1.44 in the total population, 0.87 in the 0-6-year group, and 1.88 in the 7-12-year group. For 22 patients who had previously been receiving prophylaxis, the estimated mean ABR was 1.38 versus a historical ABR of 2.51. Estimated mean steady-state FIX trough levels were 0.153 IU mL(-1) (0-6 years) and 0.190 IU mL(-1) (7-12 years). Conclusion Nonacog beta pegol was well tolerated in previously treated children with hemophilia B; a 40 IU kg(-1) dose provided effective once-weekly prophylaxis and hemostasis when bleeds were treated.
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'.
CONCLUSIONS: Nonacog beta pegol showed a favourable tolerability profile (with no safety issues identified) with good prophylactic protection and control of bleeding in previously treated adult and adolescent haemophilia B patients.