Outcomes of paediatric patients with B-cell acute lymphocytic leukaemia with ABL-class fusion in the pre-tyrosine-kinase inhibitor era: a multicentre, retrospective, cohort study

den Boer ML, Cario G, Moorman AV, Boer JM, de Groot-Kruseman HA, Fiocco M, Escherich G, Imamura T, Yeoh A, Sutton R, Dalla-Pozza L, Kiyokawa N, Schrappe M, Roberts KG, Mullighan CG, Hunger SP, Vora A, Attarbaschi A, Zaliova M, Elitzur S, Cazzaniga G, Biondi A, Loh ML, Pieters R. Outcomes of paediatric patients with B-cell acute lymphocytic leukaemia with ABL-class fusion in the pre-tyrosine-kinase inhibitor era: a multicentre, retrospective, cohort study. Lancet Haematol. 2021 Jan;8(1):e55-e66. doi: 10.1016/S2352-3026(20)30353-7. Epub 2020 Dec 22. PubMed PMID: 33357483; PubMed Central PMCID: PMC9709453.

ABL-class gene fusions other than BCR-ABL1 have been detected in ~3% of children with newly diagnosed acute lymphoblastic leukemia (ALL) and may be targeted by tyrosine kinase inhibitors (TKIs). This international study establishes the baseline characteristics and outcome of ABL-class ALL patients in the pre-TKI era. Patients’ characteristics and outcome of 122 children (1–18 years) with ABL-class B-cell precursor ALL were retrospectively collected through the Ponte di Legno consortium. Patients were enrolled in pediatric trials between 2000 and 2018 and were not exposed to TKIs during their first-line protocols. Event-free (EFS) and overall survival (OS) were determined by Kaplan-Meier methodology, and the cumulative incidence of relapse (CIR) and treatment-related mortality by a competing risk model.