Eculizumab to Treat Thrombotic Microangiopathy/Atypical Hemolytic Uremic Syndrome -Associated Multiple Organ Dysfunction Syndrome in Hematopoietic Stem Cell Transplant Recipients

This clinical trial is a prospective single arm multi-institution study in children and young
adults undergoing allogeneic or autologous hematopoietic stem cell transplantation who will
receive early therapy with eculizumab to prevent TMA-associated MODS after transplantation.
The purpose of this research study is to examine efficacy of complement blocker eculizumab in
HCT recipients with high risk TMA and to determine optimal eculizumab dosing regimen for HCT
recipients with TMA using PK/PD studies. All patients will receive therapy based on their
weight for 24 weeks. Survival will be assessed at 6 months from TMA diagnosis.

Inclusion Criteria:

- Patients of any age undergoing allogeneic or autologous HCT

- Histologic TMA diagnosis OR clinical TMA diagnosis and presenting with high risk
disease features including elevated plasma sC5b-9 above laboratory normal value
(≥244ng/ml) and proteinuria measured as ≥30mg/dL of protein on random urinalysis x2 or
protein/creatinine ratio ≥1mg/mg.

- Minimum weight of ≥ 5kg.

Exclusion Criteria:

- Known hypersensitivity to any constituent of the study medication.

- Subjects with unresolved serious Neisseria meningitides infection or progressive
severe infection.

- Patients with diagnosis of TTP as defined by ADAMST13 activity test <10%.

- Patients previously treated with eculizumab or other complement blocker for TMA.