Emicizumab Prophylaxis Combined with ITI Effective in Pediatric Patients with Severe Hemophilia A and Inhibitors

Researchers at Emory University have described successful use of a novel treatment regimen, dubbed the “Atlanta Protocol,” that involved concomitant use of Hemlibra (emicizumab) prophylaxis and immune tolerance induction (ITI) to treat pediatric patients with severe hemophilia A and inhibitors. The study group included seven children between 21 months and 12 years of age. This modified treatment strategy combines recombinant factor VIII (FVIII) or plasma-derived FVIII products to manage inhibitor levels, while Hemlibra is prophylactically administered at the same time to prevent or stop bleeding.

Six patients used three different recombinant FVIII products at 100 IU/kg three times per week, and one used a plasma-derived FVIII product at an initial dose of 50 IU/kg three times per week. Over the median 35-week follow-up period, three children experienced no bleeding events, and inhibitors were cleared or reduced to unmeasurable titers (<0.6 Chromogenic Bethesda Units per mL) in three of the seven children. Four others experienced a total of nine bleeding events, but no thrombotic events occurred in any patient.

Six children underwent surgery during the study, with no major complications or excess bleeding during or after surgery. While concluding that “immune tolerance induction while on emicizumab prophylaxis is a feasible approach in pediatric patients with inhibitors,” the investigators acknowledged prospective studies will be necessary to compare treatment outcomes to standard ITI regimens.