Paroxysmal nocturnal hemoglobinuria (PNH) is a rare stem cell disorder characterized by hemolytic anemia, bone marrow failure, and thrombosis. Until recently, the complement inhibitor, eculizumab, was the only United States Food and Drug Administration (US FDA)-approved therapy for the treatment of PNH. Although effective, eculizumab requires a frequent dosing schedule that can be burdensome for some patients and increases the risk of breakthrough intravascular hemolysis. Ravulizumab, an eculizumab-like monoclonal antibody engineered to have a longer half-life, is intended to provide the same benefits as eculizumab but with a more convenient and effective dosing schedule. In two recently published phase III non-inferiority trials, ravulizumab was found to be non-inferior to eculizumab both in efficacy and safety for the treatment of patients with PNH. Based on these results, ravulizumab was approved by the US FDA on 21 December 2018 and is currently under regulatory review in both the European Union and Japan.
