The poor prognosis of low hypodiploidy in adults with B‐cell precursor acute lymphoblastic leukaemia is restricted to older adults and elderly patients.

Summary: The prognostic significance of low‐hypodiploidy has not been extensively evaluated in minimal residual disease (MRD)‐oriented protocols for adult acute lymphoblastic leukaemia (ALL). We analysed the outcome of hypodiploid adult ALL patients treated within Programa Español de Tratamientos en Hematología (PETHEMA) protocols. The 5‐year cumulative incidence of relapse (CIR) of low‐hypodiploid B‐cell precursor (BCP)‐ALL was significantly higher than that of high‐hypodiploids (52% vs. 12%, P = 0.013). Low‐hypodiploid BCP‐ALL patients aged ≤35 years showed superior survival (71% vs. 21%, P = 0.026) and lower 5‐year CIR (17% vs. 66%, P = 0.090) than low‐hypodiploids aged >35 years. Older adults and elderly low‐hypodiploid BCP‐ALL patients show dismal prognosis although achieving an end‐induction good MRD response. [ABSTRACT FROM AUTHOR]