Improvements in hematologic markers and decreases in fatigue with pegcetacoplan for patients with paroxysmal nocturnal hemoglobinuria and mild or moderate anemia (hemoglobin ≥10 g/dL) who had received eculizumab or were naive to complement inhibitors.

BACKGROUND: Although complement component 5 inhibitors (C5is) eculizumab and ravulizumab improve paroxysmal nocturnal hemoglobinuria (PNH) outcomes, patients may experience persistent anemia. This post hoc analysis investigated whether the complement component 3-targeted therapy pegcetacoplan also improved hematologic outcomes and reduced fatigue in patients with PNH and mild/moderate anemia. METHODS: Patients with PNH and hemoglobin ≥10.0 g/dL at baseline of PADDOCK (N = 6), PRINCE (N = 8), and PEGASUS (N = 11) were included. Before receiving pegcetacoplan, PADDOCK and PRINCE patients were C5i-naive; PEGASUS patients had hemoglobin <10.5 g/dL despite stably dosed eculizumab. Hemoglobin concentrations, percentages of patients with concentrations ≥12 g/dL, and sex-specific normalization were assessed at baseline and after 16 weeks of pegcetacoplan, as were absolute reticulocyte counts (ARCs) and normalization and fatigue scores and normalization. RESULTS: From baseline to week 16, mean (SD) hemoglobin concentrations increased in C5i-naive patients (PADDOCK: 10.5 [0.4] to 12.7 [1.1] g/dL; PRINCE: 11.3 [1.0] to 14.0 [1.3] g/dL) and those with suboptimal eculizumab responses (PEGASUS: 10.2 [0.2] to 12.8 [2.6] g/dL). Percentage of patients with hemoglobin ≥12 g/dL increased (PADDOCK: 0 to 60.0% [3 of 5 patients]; PRINCE: 25.0% [2 of 8] to 87.5% [7 of 8]; PEGASUS: 0 to 72.7% [8 of 11]). Sex-specific hemoglobin normalization at week 16 occurred in 40.0% (2 of 5) (PADDOCK), 62.5% (5 of 8) (PRINCE), and 63.6% (7 of 11) (PEGASUS). In all studies, mean ARCs decreased from above normal to normal and ARC normalization increased. Mean Functional Assessment of Chronic Illness Therapy-Fatigue scores improved from below to above or near normal. Two patients had serious adverse events (PEGASUS: post-surgery sepsis, breakthrough hemolysis); breakthrough hemolysis resolved without study discontinuation. CONCLUSION: Patients with PNH and mild/moderate anemia who were C5i-naive or who had suboptimal hemoglobin concentrations despite eculizumab treatment had improved hematologic outcomes and reduced fatigue after initiating or switching to pegcetacoplan. TRIAL REGISTRATION: Trial registration numbers: PADDOCK (NCT02588833), PRINCE (NCT04085601; EudraCT, 2018-004220-11), PEGASUS (NCT03500549).