It binds to C5, preventing C5 cleavage and thus inhibiting the formation of the terminal complement complex, C5b-9.15 In SHEPHERD, a 52-week phase III open-label clinical trial of eculizumab, regular intravenous infusions resulted in 87% reduction in hemolysis, 51% of patients achieving transfusion independence.16 This was achieved through protection of PNH RBCs, with median PNH type III RBCs rising from 33.5% at baseline to 55.7% at week 52.16 Thus, eculizumab was shown to be highly effective at reducing hemolysis of PNH RBCs and thus ameliorating the anemia experienced by patients with PNH. Here, C5 is linked to anemia (phenotype).