Iptacopan monotherapy resulted in increased hemoglobin level in patients with PNH and hemoglobin ≥10 g/dL after anti-C5 therapy.

Patients with paroxysmal nocturnal hemoglobinuria (PNH) on anti-C5 often experience extravascular hemolysis with anemia. Iptacopan, the first oral proximal complement inhibitor targeting factor B, has shown efficacy and safety in PNH patients. APPULSE-PNH (NCT05630001), a phase 3b, single‑arm, open-label trial, enrolled adult patients with PNH and hemoglobin ≥10 g/dL on stable anti-C5 for ≥6 months. Patients switched to iptacopan monotherapy (200 mg twice daily; 24 weeks). Primary endpoint: mean hemoglobin change from baseline across four visits (Days 126-168). At baseline, 57.7% of patients had elevated absolute reticulocyte counts (ARCs; above ULN = 123 × 109/L) and 50% had C3 deposition on red blood cells (RBCs) >10%, indicative of extravascular hemolysis. There was a statistically significant increase in hemoglobin during the trial; adjusted mean change from baseline (95% CI) was +2.0 g/dL (1.7-2.3) overall, and in patients with baseline hemoglobin <12 g/dL and ≥12 g/dL, +2.4 (2.0-2.7) and +1.4 (1.0-1.8), respectively. Patients maintained transfusion independence, 92.7% with hemoglobin ≥12 g/dL. Adjusted mean change from baseline (95% CI) in lactate dehydrogenase and ARC were -1.3% (-6.6 to 4.3) and -89.2 × 109/L (-95.5 to -82.9), respectively. Mean (SD) proportion of C3d+ PNH RBCs, assessed by flow cytometry, decreased from 11.0% (8.6) to 0.2% (0.7) at Day 168. No patients had breakthrough hemolysis or major adverse vascular events. FACIT-Fatigue and treatment satisfaction scores improved by Days 84 and 168. Safety showed consistency with previous iptacopan PNH trials. Iptacopan improved hematologic outcomes in PNH patients with hemoglobin ≥10 g/dL on anti-C5, maintaining control of intravascular hemolysis and resolving extravascular hemolysis.