Hemolytic paroxysmal nocturnal hemoglobinuria: 20 years of medical progress

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by intravascular hemolysis, thrombosis and bone marrow failure. Prior to the availability of specific therapy, PNH led to the death of around half of affected individuals, mainly through thrombotic complications, with a particular grim prognosis for patients presenting with classic PNH. The anti-C5 monoclonal antibody eculizumab has revolutionized treatment, controlling intravascular hemolysis and thrombosis occurrence, with improved long-term survival. However, eculizumab is infused on a lifelong 2 week basis and most of the patients are anemic, with some remaining transfusion-dependent. New anti-C5 agents reproduce the safety and efficacy of eculizumab, with improved patient convenience, while proximal complement inhibitors have been developed to address C3-mediated extravascular hemolysis, aiming to eventually improve hematological response. This review will describe the spectacular medical progress in PNH of the last 20 years, as well as the risks and benefits of a novel approach.