VPB0694 - Analysis of emicizumab discontinuation in 10 patients with hemophilia A

Background: The number of patients receiving emicizumab subcutaneous injections with longer dosing intervals is rapidly increasing. Although emicizumab efficacy is widely reported, little is known about discontinuation by patients in real-world settings.

Aims: To evaluate factors contributing to emicizumab discontinuation and promoting its safe use.

Methods: We collected data from medical records of patients administered emicizumab at our hospital until the analysis in September 2021.

Results: Of 64 patients (including 9 inhibitors), 10 discontinued emicizumab (median, 23 months until discontinuation) . The mean age of these 10 was 7–69 years (table); all were non-inhibitors. Thereafter, only non-inhibitors were examined because the bleeding nature is different between inhibitors and non-inhibitors. The severity was severe (43 continued, 8 discontinued), moderate (2 continued, 1 discontinued), and mild (1 discontinued). Adherence to prophylaxis before emicizumab (continuous group [mean 89% ± 16], discontinued group [mean 94% ± 17]) and change in the annual bleeding rate during emicizumab are shown in Fig.. No patient in the discontinued group achieved zero bleeding. Reasons for discontinuation included poor bleeding control (5 patients), possible side effects (2 patients), prolonged dosing intervals due to poor understanding of the treatment (1 patient), and concerns about medical costs (1 patient). Four patients with poor bleeding control experienced frequent joint pain and bleeding sensation, and hemorrhagic synovitis was detected using joint ultrasound. Emicizumab blood levels were measured in several patients; none had low emicizumab levels. Six patients initiated prophylaxis with standard half-life products (SHLs), two with extended half-life products (EHLs), and two with SHLs before switching to EHLs.

Conclusion(s): Patients who discontinued emicizumab had experienced more bleeding before and during emicizumab use. It is important to educate patients before switching to alternate treatments.