Emicizumab in Children with Severe Hemophilia A

Objectives: To assess the effectiveness and tolerability of emicizumab prophylaxis in hemophilia A (HA). Emicizumab is a novel therapeutic drug which is the first and only non-factor replacement agent licensed for use in people with HA.

Methods: Pediatric patients aged 1 mo to 12 y with severe HA and frequent / life threatening bleeding events, with or without coagulation protein factor VIII inhibitors were enrolled (n = 18) in this observational pre-post study. Patients were switched from therapy involving on-demand or prophylactic factor VIII/bypassing agents/immune tolerance induction to emicizumab prophylaxis and followed up for 52 wk.

Results: One year before initiating emicizumab, a total of 229 bleeding events occurred among the enrolled children. After emicizumab prophylaxis, 5 patients had one episode of bleeding event each with a mean bleeding duration of 1.2 d in one year. The mean annualized bleeding rate significantly reduced from 12.7 ± 8.61 events pre-emicizumab prophylaxis to 0.28 ± 0.46 events post-emicizumab prophylaxis (p < 0.001). Out of the total cohort (n = 18), 72.2% of patients (n = 13) had no bleeding events (95% Confidence interval: 46.4-89.3) while on emicizumab. The mean annualized joint bleeding rate reduced from 9.72 ± 7.44 to 0.17 ± 0.38 (p < 0.001). The target joint resolution was 100% and no adverse events were noted.

Conclusions: Emicizumab was found to be effective and safe as a prophylactic agent for the treatment of severe HA with and without factor VIII inhibitors. Emicizumab prophylaxis can optimize treatment outcomes and promote a better quality of life in children with severe HA.