Pegcetacoplan controls hemolysis in complement inhibitor-naive patients with paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease characterized by complement-mediated hemolysis. Pegcetacoplan is the first C3-targeted therapy approved for adults with PNH (United States), adults with PNH with inadequate response to or intolerance of a C5 inhibitor (Australia), and adults with anemia despite C5-targeted therapy for 3 months (European Union). PRINCE was a phase 3, randomized, multicenter, open-label, controlled study to evaluate efficacy and safety of pegcetacoplan versus control (supportive care only; eg, blood transfusions, corticosteroids, and supplements) in complement inhibitor-naive patients with PNH. Eligible adults receiving supportive care only for PNH were randomized and stratified based on their number of transfusions (<4, ≥4) 12 months before screening. Patients received pegcetacoplan 1080 mg subcutaneously twice weekly or continued supportive care (control) for 26 weeks. Coprimary endpoints were hemoglobin stabilization (avoidance of >1-g/dL decrease in hemoglobin levels without transfusions) from baseline through week 26 and lactate dehydrogenase (LDH) change at week 26. Overall, 53 patients received pegcetacoplan (n=35) or control (n=18). Pegcetacoplan was superior to control for hemoglobin stabilization (pegcetacoplan, 85.7%; control, 0; difference, 73.1% [95% CI: 57.2, 89.0]; P <0.0001) and change from baseline in LDH (least-square mean change: pegcetacoplan, -1870.5 U/L; control -400.1 U/L; difference, -1470.4 U/L [95% CI: -2113.4, -827.3]; P <0.0001). Pegcetacoplan was well tolerated. No pegcetacoplan-related adverse events were serious, and no new safety signals observed. Pegcetacoplan rapidly and significantly stabilized hemoglobin and reduced LDH in complement inhibitor-naive patients and had a favorable safety profile. This trial was registered at www.clinicaltrials.gov as #NCT04085601.