Sustained hematologic remission after discontinuation of long-term treatment with sutimlimab. Time course of hemoglobin and bilirubin levels of the 3 included patients is shown for 3 phases: (i) washout from the NPP, (ii) long-term treatment with sutimlimab in the extension trial (abridged), and (iii) follow up after discontinuation of sutimlimab treatment. (i) The planned drug washout after end of the NPP induced the expected hemolysis in all 3 patients. (ii) Initiation of sutimlimab rapidly abrogated hemolysis and increased hemoglobin levels in all patients. (iii) In patients 1 and 2, steady near normal hemoglobin levels were observed for up to 12 months following discontinuation of sutimlimab. Bilirubin levels remained within the normal range in patient 1 and showed a small increase just above the normal range in patient 2. Patient 3 relapsed and developed transfusion-dependent anemia around 7 to 8 weeks after the last dose of sutimlimab. RBC, red blood cells.