Rurioctocog alfa pegol (BAX 855) is a novel third-generation recombinant factor VIII whose active ingredient is chemically modified with polyethylene glycol. A global multicenter phase 2/3 study of the product in 137 patients (including 11 patients from Japan) with severe hemophilia A aged 12-65 years, reported an extended half-life and a good tolerability profile, as well as a significantly lower annualized bleeding rate in the prophylactic treatment arm than in the on-demand treatment arm. Using descriptive statistics, a post hoc analysis was performed to compare the pharmacokinetics, safety, and efficacy profiles of the product in the Japanese subpopulation and the overall population. Extended half-life was demonstrated in the Japanese subpopulation. The mean [standard deviation (SD)] annualized bleeding rates in the prophylactic treatment arm were 3.7 (4.7) for the overall population (n = 120) and 4.0 (3.4) for the Japanese subpopulation (n = 11). The proportion of bleeds reported as excellent or good was 94.9% (149/157) in the overall population, whereas that in the Japanese subpopulation was 92.3% (12/13). No FVIII inhibition or anaphylactic reaction was reported in the Japanese subpopulation. The post hoc comparisons demonstrated similar pharmacokinetic, safety, and efficacy profiles between the overall population and the Japanese subpopulation.
Keywords: Annualized bleeding rate; Hemophilia A; Pegylated full-length recombinant factor VIII; Phase 2/3 clinical study; Previously treated patients.