Inclusion Criteria:  Body weight ≥ 5 kg at the time of HSCT-TMA diagnosis Documented TMA diagnosis within 6 months from the HSCT Evidence of renal dysfunction Presence of hypertension  Exclusion Criteria:  History or presence of familial or acquired 'a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13' (ADAMTS13) deficiency (activity < 5%) Shiga toxin-related hemolytic uremic syndrome (ST-HUS) Positive direct Coombs test Diagnosis of disseminated intravascular coagulation History or presence of bone marrow/graft failure Diagnosis of veno-occlusive disease Received a complement inhibitor (eg, eculizumab) post-HSCT through 12 months post TMA diagnosis