Bleeding rate reduction in children with hemophilia A and inhibitors treated with emicizumab in the real-world clinical setting

There are only limited data coming from isolated case reports regarding the real-world use of emicizumab for the treatment of children with hemophilia A and inhibitors (HAI) in Russia. The aim of the study was to evaluate the efficacy and safety of emicizumab prophylaxis in children with severe HAI. Ethical approval was not required since the study only involved the use of anonymized and generalized retrospective data obtained during routine clinical practice. We retrospectively analyzed medical records of children with HAI who had been treated with emicizumab at 11 institutions located in Russia, taking into consideration such parameters as annualized bleeding rates (ABR), annualized spontaneous bleeding rates (ASBR), annualized joint bleeding rates (AJBR) and annualized bleeding rates for bleeds requiring additional therapy (ABRRT), as well as the presence and severity of adverse events during the treatment. The median age of patients at the time of initiation of emicizumab prophylaxis was 65 (11–170) months. Before the treatment, ABR was 19.9 (95% confidence interval (CI), 15.4–26.1), ASBR – 13.6 (95% CI, 10.6–17.8), AJBR – 6.6 (95% CI, 4.7–9.7), ABRRT – 16.6 (95% CI, 12.4–22.7). After the initiation of the treatment, bleeding rates changed dramatically: ABR decreased by 98.6% (95% CI, 96.7–99.4), AJBR – by 99.4% (95% CI, 95.3–99.9), ABRRT – by 98.8% (95% CI, 96.8–99.6); and there were no signs of spontaneous bleeding during 10 (1–32) months of treatment. No adverse events leading to the interruption or discontinuation of the treatment with emicizumab were reported. The use of emicizumab in children with HAI in the real-world clinical setting results in a significant (> 98%) and safe reduction in bleeding episodes without any signs of spontaneous bleeding.