Prophylaxis for Hemophilia A with Inhibitors

Antibody formation renders factor VIII replacement therapy ineffective in up to 30% of patients with hemophilia. Preliminary studies have shown that emicizumab — a recombinant bispecific monoclonal antibody that bypasses the requirement for factor VIII — decreased the frequency of bleeding in severe hemophiliacs (NEJM JW Oncol Hematol July 2016 and N Engl J Med 2016; 374:2044).

To further evaluate emicizumab in this setting, investigators have conducted an industry-sponsored, phase III, multicenter, open-label randomized trial in 109 men with hemophilia A with a history of high titer factor VIII inhibitors. Patients received either no prophylaxis or prophylaxis with emicizumab (3 mg per kg subcutaneously weekly for 4 weeks, followed by 1.5 m…