Efficacy and Safety of Pegcetacoplan Treatment in Complement-Inhibitor Naïve Patients with Paroxysmal Nocturnal Hemoglobinuria: Results from the Phase 3 Prince Study

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and life-threatening disease characterized by hemolysis and thrombosis. Many patients with PNH use C5-inhibitors (i.e., eculizumab/ravulizumab) to control their symptoms. Although C5-inhibition prevents intravascular hemolysis (IVH), it fails to prevent extravascular hemolysis (EVH). Because of persistent EVH, up to 72% of eculizumab-treated patients remain anemic, and up to 36% require at least one transfusion per year. Pegcetacoplan (PEG), a C3-inhibitor recently approved by the US FDA to treat adults with PNH, controls IVH and prevents EVH. Studies of PEG treatment in patients with PNH that remained anemic despite eculizumab treatment demonstrated that PEG was superior to eculizumab in achieving improvements in hemoglobin (Hb) levels (Hillmen P, et al., N Engl J Med, 2021 384 (11):1028-1037). Additionally, two early phase open-label trials demonstrated the efficacy of PEG in complement-inhibitor naïve patients with PNH (Wong RS, et al., Blood, 2020 136 [Supplement 1]).