A recent phase 3, randomized, controlled trial known as the PEGASUS study (NCT03500549) enrolled patients with PNH who remained anemic (Hb ≤ 10.5 g/dL) despite stable ECU treatment (≥ 3 months) and compared pegcetacoplan treatment to ECU treatment in this population. Here, GSTM1 is linked to paroxysmal nocturnal hemoglobinuria.