AML-180: The Adverse Impact of Minimal Residual Disease Measured Before Allogeneic Hematopoietic Stem Cell Transplantation on the Outcome of Acute Leukemia Patients

Abstract

Context One of the main causes of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute leukemia (AL) patients is the disease relapse. Minimal residual disease (MRD) detected by multiparameter flow cytometry (MFC) is a strong prognostic marker of increased risk of relapse. Objective To determine the impact of MRD detected by MFC before allo-HSCT on clinical outcomes of acute leukemia patients. Patients and methods To assess the impact of MRD status before transplantation we included 84 AML patients and 46 ALL patients in their first or second morphologic remission who underwent allo-HSCT between July 2016 and April 2020. 6-color MFC was performed on bone marrow samples obtained before allo-HSCT. Positive MRD was identified as a cell population deviating from the normal patterns of antigen expression on specific cell lineages at specific stages of maturation for all patients. For patients with LAIP at diagnosis, positive MRD was also defined as a cell population carrying LAIP markers at diagnosis. The probabilities of overall survival (OS), relapse-free survival (RFS), and cumulative incidence of relapse (CIR) were estimated using the Kaplan–Meier method. Results Among 84 AML patients before allo-HSCT 23 patients (27.4%) were identified as MRD+. 11 out of 46 ALL patients (23.9%) before allo-HSCT were MRD+. Subsequently, 9 out of in 23 MRD+AML patients and 4 out of 61 MRD−AML patients relapsed (CIR 50.6% vs. 10%, p Conclusions Despite the presence of morphological complete remission before allo-HSCT, MRD persistence before allo-HSCT influences OS and RFS in patients with AL. Because of the association between MRD and relapse risk, MRD-testing before allo-HSCT may help to identify a subgroup of acute leukemia patients who need preemptive treatment.