Role of minimal residual disease and chimerism after reduced-intensity and myeloablative allo-transplantation in acute myeloid leukemia and high-risk myelodysplastic syndrome

Abstract Early response to therapy is one of the most important prognostic factors in acute leukemia. It is hypothesized that early immunophenotypical evaluation may help identify patients at high risk for relapse from those who may remain in complete remission (CR). Using multiparametric flow cytometry, the level of minimal residual disease (MRD) was evaluated in the first bone marrow (BM) in morphologic CR obtained after induction treatment from 126 patients with acute myeloid leukemia (AML) who displayed aberrant phenotypes at diagnosis. Based on MRD level, 4 different risk categories were identified: 8 patients were at very low risk (fewer than 10−4 cells), and none have relapsed thus far; 37 were at low risk (10−4 to 10−3 cells); and 64 were at intermediate risk (fewer than 10−3 to 10−2 cells), with 3-year cumulative relapse rates of 14% and 50%, respectively. The remaining 17 patients were in the high-risk group (more than 10−2 residual aberrant cells) and had a 3-year relapse rate of 84% (P = .0001). MRD level not only influences relapse-free survival but also overall survival (P = .003). The adverse prognostic impact was also observed when M3 and non-M3 patients with AML were separately analyzed, and was associated with adverse cytogenetic subtypes, 2 or more cycles to achieve CR, and high white blood cell counts. Multivariate analysis showed that MRD level was the most powerful independent prognostic factor, followed by cytogenetics and number of cycles to achieve CR. In conclusion, immunophenotypical investigation of MRD in the first BM in mCR obtained after AML induction therapy provides important information for risk assessment in patients with AML.

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Monitoring of Post-Transplant MLL-PTD as Minimal Residual Disease Can Predict Relapse After Allogeneic HSCT in Patients With Acute Myeloid Leukemia and Myelodysplastic Syndrome

10.21203/rs.3.rs-601950/v1 ◽

2021 ◽

Author(s):

Jun Kong ◽

Meng-Ge Gao ◽

Ya-Zhen Qin ◽

Yu Wang ◽

Chen-Hua Yan ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Myelodysplastic Syndrome ◽

Minimal Residual Disease ◽

Myeloid Leukemia ◽

Residual Disease ◽

Hematopoietic Stem ◽

Post Transplant ◽

Significant Difference ◽

Minimal Residual ◽

Acute Myeloid

Abstract Background: MLL-PTD is a special MLL rearrangement gene that occurs in about 5-10% of acute myeloid leukemia (AML) with a normal karyotype and in 5-6% of myelodysplastic syndrome (MDS) patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently one of the curative therapies available for AML and MDS with excess blasts (MDS-EB). However, how the prognosis of patients with high levels of MLL-PTD after allo-HSCT, including AML and MDS, and whether MLL-PTD could be used as a reliable indicator for minimal residual disease (MRD) monitoring in transplant patients remains unknown. Our study purposed to analyze the dynamic changes of MLL-PTD peri-transplantation and the best threshold for predicting relapse after transplantation.Methods: We retrospectively collected the clinical data of 48 patients with MLL-PTD AML or MDS-EB who underwent allo-HSCT in Peking University People’s Hospital. The MLL-PTD was examined by real-time quantitative polymerase chain reaction (RQ-PCR) at the diagnosis, before transplantation and the fixed time points after transplantation. Detectable MLL-PTD/ABL>0.08% was defined as MLL-PTD positive in this study.Results: The 48 patients included 33 AML patients and 15 MDS-EB patients. The median follow-up time was 26(0.7-56) months after HSCT. In AML patients, 7 patients (21.2%) died of treatment-related mortality (TRM), 6 patients (18.2%) underwent hematological relapse and died ultimately. Of the 15 patients with MDS-EB, 2 patients (13.3%) died of infection. The 3-year cumulative incidence of relapse (CIR), overall survival (OS), disease-free survival (DFS) and TRM were 13.7%±5.2%, 67.8%±6.9%, 68.1%±6.8% and 20.3%±6.1%, respectively. ROC curve showed that post-transplant MLL-PTD≥1.0% was the optimal cut-off value for predicting hematological relapse after allo-HSCT. There was statistical difference between post-transplant MLL-PTD≥1.0% and MLL-PTD<1.0% groups (3-year CIR: 75%±15.3% vs. 0%, P<0.001; 3-year OS: 25.0±15.3% vs. 80.7%±6.6%, P<0.001; 3-year DFS: 25.0±15.3% vs. 80.7%±6.6%, P<0.001; 3-year TRM: 0 vs. 19.3±6.6%, P=0.277). However, whether MLL-PTD≥1% or MLL-PTD<1% before transplantation has no significant difference on the prognosis. Conclusions: Our study indicated that MLL-PTD had a certain stability and could effectively reflect the change of tumor burden. The expression level of MLL-PTD after transplantation can serve as an effective indicator for predicting relapse.

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