Inhibitory hemophilia: contemporary treatment with emicizumab. Considerations for pediatric practice

Abstract

Introduction. This article provides an overview of current knowledge and global experience regarding the use of emicizumab, with a focus on its specific considerations in pediatric practice. Emicizumab, a monoclonal antibody, operates uniquely compared to other therapies. It has been approved in Moldova since 2019 for preventing bleeding in hemophilia patients. Significant data from clinical studies and accumulated clinical practice provide answers to most questions physicians have when prescribing emicizumab. The article presents recommendations based on current information and global experience to aid decision-making in emicizumab usage. The purpose of this article is to provide information on management tactics for pediatric patients with hemophilia A receiving emicizumab. Materials and methods. Over 40 publications were reviewed, consisting of recommendations, study results, and observations related to emicizumab use in pediatric patients with Hemophilia A. Results. In 2017, emicizumab became the first registered non-factorial therapy for Hemophilia A. It was approved for use in treating the inhibitory form of the condition. In 2018, indications for emicizumab were expanded to include patients with the inhibitory form of hemophilia A and severe hemophilia A without inhibitors. Emicizumab is used to prevent bleeding and is not intended to stop an already occurring bleeding. If bleeding has occurred, the patient will need to be prescribed FVIII or bypassing agents. Emicizumab is administered as a loading dose of 3 mg/kg once a week for the first 4 weeks, followed by a maintenance dose of 1.5 mg/kg once a week, 3 mg/kg once every two weeks, or 6 mg/kg once every four weeks. The dose is based on the patient’s body weight, which needs regular monitoring. If a dose is missed, it should be administered as soon as possible before the next scheduled dose, and the injection schedule should not be altered. Emicizumab can be used in children under one year to prevent bleeding. Conclusions. Hemophilia, caused by a deficiency in coagulation factors VIII or IX, is a bleeding disorder. The main treatment-related complication in hemophilia patients is the development of inhibitors – alloantibodies that neutralize the procoagulant activity of infused FVIII or factor IX. The reasons why only 20%-30% of Hemophilia A patients develop inhibitors remain a challenge. Emicizumab, a bispecific monoclonal antibody, bridges the gap between activated factor IX and factor X to replace the missing activated factor VIII, thereby restoring hemostasis.