Real-world data on the use of emicizumab in patients with haemophilia A with and without inhibitors in Singapore.

Introduction: Emicizumab is a bispecific monoclonal antibody that mimics the function of factor VIII by binding to factor IXa and factor X to achieve haemostasis in haemophilia A. The long half-life and subcutaneous mode of administration makes emicizumab a compelling treatment option for bleeding prophylaxis. There is still limited real-world data on its use and management considerations, especially during surgical procedures. The objective of the study is to describe the real-world experience of emicizumab in a cohort of adult and paediatric haemophilia A patients in Singapore, including its use in the periprocedural setting.

Method: This was an observational study conducted at the 2 main haemophilia treatment centres in Singapore. All haemophilia A patients who commenced treatment with emicizumab before 1 July 2022 were recruited.

Results: A total of 18 patients with haemophilia A were included in this study. Ten (55.6%) patients had active inhibitors. The median annual bleeding rate for all patients before emicizumab use was 4.5 events (interquartile range [IQR] 2.8-8.3) compared with 0 events (IQR 0-0) after emicizumab was commenced (P=0). There were no adverse events of venous or arterial thrombosis, thrombotic microangiopathy, or death. A total of 6 procedures in 5 patients were performed during the study period with no major bleeding complications.

Conclusion: Emicizumab effectively protects against bleeding in haemophilia A patients with and without inhibitors, including in children less than 12 years old. More studies are required to address clinical nuances, such as periprocedural management and the role of immune tolerance in patients with inhibitors on emicizumab.