Statistical analysis
R-R pre-B ALL
This is a phase II study in R-R pre-B ALL in which 110 consecutive patients were treated. The trial was continuously monitored, with an early stopping rule in place if it was ever likely that the trial’s OS was less than that of previous similar trials. No stopping rules were met. Survival curves were plotted by the Kaplan–Meier method and compared with the log-rank test. Differences in subgroups were evaluated with the Chi-squared test for nominal values and the Mann–Whitney U and Fisher exact tests for continuous variables. A 