Emicizumab for hemophilia A without inhibitors

Introduction: Hemophilia A (HA) is an inherited bleeding disorder that, if not properly treated, is associated with debilitating joint damage due to recurrent hemarthroses as well as life-threatening bleeds including intracranial hemorrhage. For decades, the only method to prevent bleeding events was to infuse factor (F) VIII concentrates intravenously two to three times weekly. Although successful in reducing bleeding frequency, preventing a high proportion of joint disease, and extending life expectancy, standard continuous prophylaxis with FVIII is burdensome and insufficiently effective at preventing long-term joint dysfunction in some patients. In October 2018, the Federal Drug Administration approved a novel agent, emicizumab-kxwh, for the treatment of patients with HA without inhibitors. Areas covered: In this article, the preclinical and clinical development of emicizumab-kxwh will be reviewed. Data from licensure phase 3 clinical trials will be reviewed in detail discussing issues of both safety and efficacy. Expert opinion: As emicizumab-kxwh leads the way of a shift in treatment paradigm for patients with HA without inhibitors, a number of questions remain, including the impact of emicizumab-kxwh on joint and bone health, inhibitor development, and thrombotic risk. Ultimately, time and clinical investigation will be able to elucidate the influence of emicizumab-kxwh in these areas.