Results
Twenty-nine children (17 within target) were evaluated. All subjects engrafted neutrophils with a median (IQR) time of 14 days (8-30 days). The cumulative incidence of acute graft versus host disease was 44.8% (95% CI 35.6 – 54.0%), while chronic graft versus host disease was noted in 16.0% (95% CI 8.7% - 23.3%). At two years, the overall survival was 78.1% (95% CI 70.8% - 86.4%) and event free survival was 74.7% (95% CI 66.4% - 83.0%). Cumulative incidence of relapse was 11.3% (95% CI 5.1% - 17.5%). There were no statistically significant differences in between the group that received targeted busulfan compared with the untargeted group.