Statistical analysis
Complete remission (CR) was defined as less than 5% lymphoblasts in active hematopoietic marrow, absence of leukemic cells in peripheral blood, absence of leukemic cells in cerebrospinal fluid or absence of leukemic infiltrates elsewhere in the body after induction chemotherapy. Resistant disease was defined as failure to achieve CR. Relapse was defined (see protocol for more details) as recurrence of leukemic blasts at any involvement site. Treatment abandonment was defined as the treatment stop due to any reason except for death. CNS involvement was defined by the presence of leukemia cells and more than 5 nucleated cells per microliter cerebrospinal fluid (CNS 3).
Event-free survival was defined as the time from diagnosis to the date of last follow-up or first event. Events were nonresponse, relapse, or death from any cause. Failure to achieve remission due to death before complete remission or nonresponse was considered as event at time 0. Overall survival was defined as the time from diagnosis to the date of last follow-up or death. The Kaplan-Meier method was used to estimate survival rates; differences between groups were compared with the log-rank test. Standard error (SE) is provided for all estimates. Statistical analysis was done using GraphPad Prism 8 (GraphPad software) and SAS 9.4 (SAS Institute, Cary, NC).