Plain Language SummaryParoxysmal nocturnal hemoglobinuria (PNH) is a rare and potentially life-threatening blood disorder where an acquired genetic mutation causes a patient’s complement system (a part of the immune system) to attack and destroy red blood cells, which can lead to symptoms including anemia and the formation of blood clots. For many years, the standard treatment for PNH has been complement 5 (C5) inhibitors, which target a downstream part of the complement signaling pathway. However, many PNH patients on C5 inhibitors continue to experience symptoms of the disease, including anemia and impaired quality of life (QoL). Recently, pegcetacoplan, a novel complement inhibitor targeting the complement 3 protein (an upstream part of the complement system) was shown to be superior to a C5 inhibitor in key patient outcome measures in the phase 3 clinical trial PEGASUS, including raising hemoglobin levels and improving QoL. Japanese patients with PNH are known to have different clinical and pathological features from non-Asian PNH patients. Here, we report findings of a post-hoc analysis which evaluated the efficacy, safety, and QoL in Japanese patients treated with pegcetacoplan in PEGASUS. Consistent with findings in the overall study population, our results show that Japanese PNH patients treated with pegcetacoplan derived durable treatment benefits across key outcome measures, including increasing hemoglobin levels and improving QoL scores. The safety outcomes were also similar between Japanese patients and the overall study population. Together, these findings indicate that Japanese PNH patients can be effectively and safely treated with the newly approved C3 inhibitor pegcetacoplan.