A myeloablative conditioning regimen with fludarabine demonstrates good results in UCBT for 30 pediatric patients with hematologic malignancies, especially acute lymphoblastic leukemia.

We retrospectively analyzed the safety and efficacy of a myeloablative conditioning regimen with fludarabine (FLU) in unrelated cord blood transplantation (UCBT) of 30 pediatric patients with hematologic malignancies. The conditioning regimen consisted of FLU, busulfan (BU) and cyclophosphamide (CY). All of the patients received Cyclosporine (CSA) and mycophenolate mofetil (MMF) as graft versus host disease (GVHD) prophylaxis. We achieved high engraftment rates (96.7%) and rapid hematopoietic reconstitution. Acute GVHD occurred in 12 cases of the 29 engraftment patients (41.4%), and 6 cases (20.7%) were of grade III-IV. Chronic GVHD only occurred in 1 of 28 evaluable patients (3.6%). Twenty-three patients (76.7%) became infected, and 3 cases (10.0%) died of severe infections. Cytomegalovirus (CMV) reactivation occurred in 70.0% of the patients, but no CMV diseases were observed, nor did any patients die of CMV infection. The cumulative incidence of relapse (6.7%) was significantly reduced, and none of the acute lymphoblastic leukemia (ALL) patients relapsed. The 3-year overall survival (OS) and event-free survival (EFS) rates were 73.3% and 70.0%, respectively. The 3-year OS and EFS of the ALL patients was 75.0%. This conditioning regimen demonstrates good results and security in UCBT, especially in acute lymphoblastic leukemia.