Minimizing Toxicity in HLA-identical Sibling Donor Transplantation for Children With Sickle Cell Disease

This is a prospective, multicenter phase II study of HLA-identical sibling donor HSCT in 30 pediatric patients with SCD using nonmyeloablative conditioning with alemtuzumab, total-body irradiation, and sirolimus. The primary Objective of this study is to determine if the SUN regimen can decrease the incidence of grade II-IV acute graft-versus host disease (GVHD) by day +100 while maintaining similar disease-free survival compared to establish HLA-identical donor hematopoietic stem cell transplant (HSCT) regimens in children with SCD. The secondary Objective is to determine if health-related quality of life (HRQoL) for children undergoing SUN HSCT is preserved during the early post-transplant time period. To determine if the SUN regimen can decrease the number of platelet transfusions compared to established HLA-identical HSCT regimens in children with SCD. The tertiary/Exploratory Objectives: To describe other markers of toxicity (duration of neutropenia, mucositis, length of hospitalization) and indicators of a successful HSCT (HRQoL at 1 year, proportion needing additional immunosuppression during the first year, proportion able to wean sirolimus at 1 year). With protocol version 5.0, added new secondary objective to determine if the change from intravenous to subcutaneous alemtuzumab and the addition of post-HSCT G-CSF can decrease the incidence of poor donor engraftment.