Efficacy of emicizumab in patients with severe haemophilia A without factor VIII inhibitors in Germany: evaluation of real-life data documented by the smart medication eDiary

Background: Systematically documented data on real-world use of emicizumab, a bispecific antibody factor (F)VIII mimetic, are still lacking in people with severe haemophilia A (PwSHA). Smart medication, a real-time, online platform, monitors treatment administration and outcomes for people with haemophilia A in Germany. Objective: To evaluate annualised bleeding rates (ABRs) and annualised joint bleeding rates (AJBRs), using data documented in the smart medication eDiary, for PwSHA receiving emicizumab. Design: Data for 97 PwSHA without FVIII inhibitors who started emicizumab treatment between 1 January 2018 and 31 March 2023, with >24 weeks of documentation after switching from FVIII replacement, were collected in the smart medication eDiary. Those with ⩾24 weeks of pre-emicizumab data were included for analysis 24 weeks before and after switching. Methods: The primary objective was to evaluate ABR and AJBR for treated bleeds. The proportion of bleed-free participants was calculated and administration frequency for FVIII and emicizumab were collected. The mean dosing frequencies for FVIII replacement and emicizumab were also evaluated. Results: The mean calculated ABR and AJBR were 0.64 and 0.39, respectively, after initiating emicizumab. For those with documentation before starting emicizumab ( n = 58), ABR decreased by 79.6% and AJBR decreased by 90.8%. The proportion of bleed-free participants increased by 21.3%, and joint bleed-free participants increased by 18.2%. The median FVIII dosing frequency was every 3.5 days ( n = 54; range: 1.0–20.8); median emicizumab dosing frequency was every 11.2 days ( N = 97; range: 6.6–29.4). Conclusion: Real-world data collected using the smart medication eDiary provide insights into efficacy outcomes after switching from FVIII replacement to emicizumab prophylaxis. Bleeds, including joint bleeds, decreased after switching.