Treosulfan/Fludarabine/Low Dose TBI as a Preparative Regimen for Children With AML/MDS Undergoing Allo HCT

The proposed study will evaluate a regimen using treosulfan, fludarabine and low-dose TBI in children and adolescents with AML or MDS undergoing allogeneic HCT. We expect this regimen to yield lower toxicity and at least equivalent rates of disease control and overall survival, compared to current standard myeloablative regimens. The primary objective of this study is to determine the safety and preliminary efficacy of a transplant preparative regimen consisting of treosulfan, fludarabine and low-dose TBI for children with AML and MDS. The primary endpoint will be overall survival (OS) at one year. Secondary objectives to be studied include: pharmacokinetic (PK) profile of treosulfan in children \< 40 kg, non-relapse mortality, disease-free survival, incidences of neutrophil and platelet engraftment, donor chimerism, acute and chronic graft-versus-host disease (GVHD), and relapse.