Rational Response-Adapted Risk Stratification and Treatment for Children with Late Bone Marrow Relapses of B-Cell Precursor Acute Lymphoblastic Leukaemia: A Report from the ALL-REZ BFM Trial Group

Background: Minimal residual disease (MRD) supports a more accurate assessment when children and adolescents with late bone marrow relapses of B-cell precursor (BCP) acute lymphoblastic leukaemia (ALL) will benefit from allogeneic haematopoietic stem cell transplantation (alloHSCT). A more detailed dissection of MRD heterogeneity, dynamics and the specific genetic aberrations involved promises to further improve treatment stratification. Methods: Patients treated according to the ALL-REZ BFM 2002 trial/registry protocol with late BCP ALL bone marrow relapses (n=413) were included. AlloHSCT was indicated for patients with MRD≥10-3 after induction treatment (poor response). Findings: Patients with good (MRD