Efficacy, safety and pharmacokinetics of recombinant human coagulation factor VIII (omfiloctocog alfa) in previously treated Chinese children with severe hemophilia A

Introduction Omfiloctocog alfa, the first China-developed recombinant factor VIII (FVIII), demonstrated efficacy and safety of prophylaxis in previously treated patients (PTPs) aged >= 12 years with severe hemophilia A in China. Aims To investigate efficacy, safety and pharmacokinetics (PK) of omfiloctocog alfa in pediatric PTPs with severe hemophilia A in China. Methods PTPs (>50 exposure days [ED] for Chinese patients aged 150 EDs for patients aged 6-12 years) were treated with omfiloctocog alfa at 25-50 IU/kg every other day or three times per week for 24 weeks. PK was evaluated after single injection of 50 IU/kg. The primary efficacy endpoint was annualized bleeding rate (ABR). Results A total of 69 patients were enrolled (<6 years, n = 35; 6-12 years, n = 34) and mean exposure to omfiloctocog alfa was 78.9 days. Mean half-life was 6.7 and 10.2 h in children < 6 years and 6-12 years, respectively. Estimated mean ABRs of all patients were 4.05 for overall bleeding episodes and 1.38 for spontaneous bleeding episodes. Of 127 bleeding episodes, the success rate was 92.1%. 39.7% patients did not experience any bleeding episodes and the mean weekly dose of FVIII was 109.1 IU/kg for these patients. 83% bleeding episodes were controlled with <= 2 injections. Adverse reactions occurred in 2.9% of the patients. One 2-year-old patient developed inhibitors after 12 EDs and it resolved with omfiloctocog alfa immune tolerance induction. Conclusion Omfiloctocog alfa was efficacious and well tolerated for the prevention and treatment of bleeding in Chinese pediatric PTPs with severe hemophilia A.