Patients at high risk of relapse other than those with persistent MRD pre and/or post allo-HCT were included such as complete hematologic remission beyond first CR at the time of allo-HCT, primary induction failure requiring more than one line of treatment, and/or high-risk cytogenetic or molecular profile defined as Ph-positive ALL, Ph-like ALL, KMT2A gene rearrangement, complex cytogenetics, or hypodiploid cytogenetics at diagnosis. Here, KMT2A is linked to acute lymphoblastic leukemia.