AML-267: Minimal Residual Disease Predicts the Outcome of Allogeneic Hematopoietic Cell Transplantation in Acute Myeloid Leukemia in the First Remission

Abstract

Context: The independent influence of pre-transplant MRD status on the results of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is now being widely reported. The genetic and immunophenotypic diversity of AML is a problem for monitoring MRD in daily clinical practice. The most widely used methods for assessing MRD are multiparametric flow cytometry (MFC) and PCR. Objective: To assess the impact of pre-transplant MRD status determined by MFC or PCR on the long-term results of allo-HSCT. Patients and Methods: The study included 106 patients with AML in the 1st CR who underwent allo-HSCT in our center from September 2015 to December 2020. The median follow-up was 19.5 (1–50) months. Eleven-color MFC was performed on bone marrow samples obtained before allo-HSCT. In 46 out of 106 patients who had molecular markers (NPM1, FLT3, RUNX1-RUNX1T1, MLL, or CBFβ-MYH11), the MRD status was determined using PCR also. Cox proportional hazards models were used to assess the influence of various independent factors on the probability of relapse (PR). The factors included in the model were ELN risk, donor type, conditioning regimen, graft source, pre-transplant MRD status, and age. The probabilities of DFS and relapse were estimated using the Kaplan-Meier method. Results: Out of 106 patients, 22 were identified as MRD+ MFC, 84 patients were MRD- MFC, 16 patients were MRD+ PCR, and 30 patients were MRD- PCR. Statistical analysis revealed significant differences between MRD+ and MRD- patients, regardless of the research method: patients with MRD+ status had the worst DFS (MFC: 24% versus 64%, p 40 y (HR=7.006) were independent factors influencing the probability of relapse. Conclusions: MRD, regardless of whether it is determined by MFC or PCR, ELN risk, and older age are independent predictors of disease recurrence risk. The study of MRD in AML patients before allo-HSCT can be used to stratify the risk of allo-HSCT and identify patients who need prophylactic post-transplant therapy to prevent disease relapse.