- Acute leukemia participants: <60 years old in second relapse or relapsing after allogeneic stem cell transplantation (aSCT) regardless of number of relapses; >60 years old in first relapse with a disease-free interval (DFI) <12 months or further relapse; irrespective of age, in participants relapsing after aSCT, the time elapsed since aSCT should be >90 days; participants with B-cell ALL: Philadelphia chromosome positive (Ph+) must have received ≥2 lines of therapy, including 2 bcr-abl tyrosine-kinase (TK) inhibitors (among imatinib, nilotinib and dasatinib), or only 1 line including 1 TK inhibitor, if the relapse/refractoriness is associated with the detection of a resistance mutation to these inhibitors