Efficacy and Safety of Recombinant Factor VIII in Previously Untreated and Previously Treated Children with Hemophilia A: A Systematic Review.

Introduction: Inhibitor development is a primary concern for pediatric patients with hemophilia A (HA) undergoing recombinant factor VIII (rFVIII) therapy, yet relevant research is lacking. We aimed to compare the efficacy and safety of standard (SHL) and extended half-life (EHL) rFVIII products in previously treated (PTPs) and untreated (PUPs) pediatric patients with HA.

Methods: Following PRISMA guidelines, we searched clinical studies from PubMed, Embase, and Cochrane Library. Data were extracted and a single-arm meta-analysis was performed.

Results: This systematic review included 16 studies involving 1145 patients. Three studies reported changes in annual bleeding rate (ABR); their results displayed no statistically significant difference in ABR changes in pediatric patients with HA after rFVIII treatment. Ten studies reported inhibitor development, nine focused on PUPs. Here, EHL rFVIII showed a proportion of inhibitors at 27.5% (95% confidence interval [CI] 22.6%; 32.6%), and third-generation SHL rFVIII showed a proportion of inhibitors at 36.4% (27.2%; 46.2%), with a high-titer proportion of 20.9% (12.9%; 30.3%) for the latter. Both SHL rFVIII (octocog alfa) and EHL rFVIII (rurioctocog alfa pegol) presented low proportions of inhibitor development. Octocog alfa exhibited the lowest high-titer inhibitor incidence, marked at 12.7% (5.3%; 24.5%). Eleven studies addressed adverse events (AEs), with octocog alfa showing low reported treatment-related AEs at a proportion of 14.5% (6.5%; 26.7%).

Conclusion: Our analysis revealed that both octocog alfa and rurioctocog alfa pegol showed low inhibitor development, with octocog alfa having few treatment-related AEs. Regular monitoring for inhibitors during rFVIII therapy is important.