In the randomized, multicenter, open-label, phase III HAVEN 1 study, patients with hemophilia A and inhibitors who were treated with the investigational bispecific monoclonal antibody emicizumab experienced a statistically significant reduction in the number of bleeds compared with patients who received no treatment (p value not provided).
HAVEN 1 enrolled 109 patients (≥12 years) who were previously treated with an episodic bypassing agent; patients were randomized 2:1 to receive emicizumab prophylaxis (Arm A) or no prophylaxis (Arm B). In Arm C, patients who were previously treated prophylactically with bypassing agents were given emicizumab prophylaxis.
The study met its primary endpoint (reduction in the number of bleeds), though the data are not yet reported. Two patients had thromboembolic events, neither of which required anticoagulation therapy; one of those patients went on to restart emicizumab. In addition, two patients developed thrombotic microangiopathy, both of which were resolved; one of those patients went on to restart emicizumab.
Emicizumab was administered via once-weekly subcutaneous injections; future trials will examine less frequent dosing schedules.
Source: Roche media release, December 22, 2016.