Real-world experience of emicizumab prophylaxis in Korean children with severe hemophilia A without inhibitors.

Purpose: Hemophilia A is a genetic disorder characterized by a lack of factor VIII (FVIII). Emicizumab, a recombinant humanized bispecific monoclonal antibody, mimics the function of FVIII. In this article, we present data on an initial real-world evaluation of emicizumab use in Korean children with severe hemophilia A without inhibitors.

Methods: This study was conducted from June 2020 to March 2024 at 4 centers in Korea. The participants were pediatric patients with severe hemophilia A without inhibitors who had received emicizumab treatment for over 6 months. The mean and median annualized bleeding rates (ABRs) and mean and median annual joint bleeding rates (AJBRs) were compared.

Results: Each of the 21 patients in the study received an emicizumab loading regimen of 3 mg/kg weekly for 4 weeks, followed by a modified maintenance regimen of which 2 patients (9.5%) received a 1.5 mg/kg weekly dose, 3 patients (14.3%) received a 6 mg/kg dose every 4 weeks, and the remaining 16 patients (76.2%) received a 3 mg/kg dose every 2 weeks. Before emicizumab prophylaxis initiation, the mean and median ABRs for all patients were 7.04 (SD ± 5.83) and 6.52 (range 0-21.74), respectively. After receiving emicizumab treatment, the mean and mediam ABRs decreased to 0.41 and zero, respectively. Additionally, 85.7% of the patients achieved no bleeding events within 6 months of starting the treatment.

Conclusion: These first real-world data in Korea indicate that emicizumab is effective and safe for pediatric patients with severe hemophilia A without inhibitors.