Cord Blood Transplantation from Unrelated Donor for Treatment of Childhood Acute Myeloid Leukemia: A Japan Cord Blood Bank Network Analysis.

Results of cord blood transplantation (UCBT) from unrelated donor in childhood acute myeloid leukemia (AML) in Japan have not been previously reported. We analyzed 162 children receiving UCB transplants for AML [78 in low risk group (first or second complete remission; CR1 or CR2 and 84 in more advanced stage (high risk group)). Poor prognosis cytogenetic abnormalities were identified in 32 cases. Most patients received a 1 or 2 HLA antigens-mismatched UCB transplants. The median number of collected nucleated cells (NCs) was 4.7 x 107/kg. Cumulative incidence (CI) of neutrophil recovery was 79.5% +/− 3.2%%(71.5% +/− 5% in high risk group, and 88.3% +/− 3% in low risk group). The median time to neutrophil recovery was 27 day. In multivariate analysis, the significant factor influencing neutrophil engraftment was low risk group. Platelet recovery was 58.7% +/− 4.0%, acute graft-versus-host disease (GVHD) was 50% +/− 5%, and transplantation-related mortality (TRM) was 29.9% +/− 5%(13.6% +/− 4.4% in low risk group, and 51.4% +/− 10% for children in high risk group). The 5-year CI of relapse was 29% +/− 3% and was associated with disease status. The 5-year event-free survival (EFS) was 38.5% +/− 3% (55.6% +/− 7.9% in low risk group, and 22.8% +/− 5.8% for high risk group). The 5-year over all survival (OS) was 39.8% +/− 3% (65.6% +/− 8% in low risk group, and 17.4% +/− 5% for high risk group). In multivariable analysis, a low risk group was associated with good 5-year survival rates. Poor cytogenetic features had no significant influence on OS and EFS, respectively. We conclude that UCBT is a therapeutic option for children with very poor-prognosis AML and who lack an HLA-identical sibling.