Hemophilia A is a genetic deficiency in clotting factor VIII, which results in increased bleeding. Recent studies have found that emicizumab, a bispecific monoclonal antibody, can be helpful in replacing the functioning of the missing activated factor VIII, and thus, restore hemostasis. This study aims to investigate the efficacy of emicizumab prophylaxis in patients with hemophilia A without factor VIII inhibitors.

This randomized trial included a total of 152 participants aged 12 years or older with hemophilia A without factor VIII inhibitors. The participants were randomly assigned in a 2:2:1 ratio to receive a subcutaneous maintenance dose of 1.5 mg/kg emicizumab (group A), 3.0 mg/kg emicizumab (group B), or no prophylaxis (group C). The primary outcome of the study was a change in the bleeding rate.

The results suggested that the annualized bleeding rate was significantly low in group A (1.5 events) and group B (1.3 events), as compared with group C (38.2 events). The rate of bleeding was, therefore, 96% lower in group A and 97% lower in group B.

The research concluded that emicizumab prophylaxis was associated with a significantly reduced event rate of annualized bleeding in patients with hemophilia A without factor VIII inhibitors.

Ref: https://www.nejm.org/doi/full/10.1056/NEJMoa1803550