Integrated prognostic value of MRD and cytogenetics in adolescent and adult B‐cell acute lymphoblastic leukaemia

Summary B‐cell acute lymphoblastic leukaemia (B‐ALL) in adolescents and adults remains challenging due to high relapse rates and suboptimal outcomes. Although minimal residual disease (MRD) and cytogenetic risk classification are independent prognostic indicators for B‐ALL in adolescents and adults, their combined utility remains under explored. This retrospective study analysed 609 adolescent and adult patients with B‐ALL to evaluate the integrated prognostic value of MRD at end of induction (MRD1) and after first consolidation (MRD2), combined with cytogenetic risk stratification (standard risk [SR] vs. poor risk [PR]). Although cytogenetic risk alone was not an independent prognostic factor, MRD positivity at either time point significantly predicted inferior 5‐year RFS and OS in PR patients. Allogeneic haematopoietic stem cell transplantation (allo‐HSCT) improved outcomes overall; however, PR patients with MRD2 positivity remained at high risk of relapse post‐transplant. Multivariate analysis identified MRD1 and MRD2 as independent predictors of both relapse (RFS HR = 2.048) and mortality (OS HR = 1.979) in PR patients (all p < 0.01). These results demonstrate that combining MRD assessment with cytogenetic risk improves risk stratification, precisely identifying poor‐risk patients with persistent MRD who may benefit from treatment intensification, including novel strategies post‐transplant.