Minimal residual disease assessed by multi-parameter flow cytometry is highly prognostic in adult patients with acute lymphoblastic leukaemia.

The prognostic value of minimal residual disease ( MRD) assessed by multi-parameter flow cytometry ( MFC) was investigated among 340 adult patients with B-cell acute lymphoblastic leukaemia (B- ALL) treated between 2004 and 2014 using regimens including the hyper CVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone, methotrexate, cytarabine) backbone. Among them, 323 (95%) achieved complete remission ( CR) and were included in this study. Median age was 52 years (range, 15-84). Median white blood cell count ( WBC) was 9·35 × 10⁹/l (range, 0·4-658·1 ×1 0⁹/l). MRD by MFC was initially assessed with a sensitivity of 0·01%, using a 15-marker, 4-colour panel and subsequently a 6-colour panel on bone marrow specimens obtained at CR achievement and at approximately 3 month intervals thereafter. MRD negative status at CR was associated with improved disease-free survival ( DFS) and overall survival ( OS) ( P = 0·004 and P = 0·03, respectively). Similarly, achieving MRD negative status at approximately 3 and 6 months was associated with improved DFS ( P = 0·004 and P < 0·0001, respectively) and OS ( P = 0·004 and P < 0·0001, respectively). Multivariate analysis including age, WBC at presentation, cytogenetics (standard versus high risk) and MRD status at CR, 3 and 6 months, indicated that MRD negative status at CR was an independent predictor of DFS ( P < 0·05). Achievement of an MRD negative state assessed by MFC is an important predictor of DFS and OS in adult patients with ALL. [ABSTRACT FROM AUTHOR]