The prognostic value of measurable residual disease (MRD) by flow cytometry in acute myeloid leukemia (AML) patients treated with non-intensive therapy is relatively unexplored. The clinical value of MRD threshold below 0.1% is also unknown after non-intensive therapy. In this study, MRD to a sensitivity of 0.01% was analyzed in sixty-three patients in remission after azacitidine/venetoclax treatment. Multivariable cox regression analysis identified prognostic factors associated with cumulative incidence of relapse (CIR), progression-free survival (PFS) and overall survival (OS). Patients who achieved MRD < 0.1% had a lower relapse rate than those who were MRD ≥ 0.1% at 18 months (13% versus 57%, p = 0.006). Patients who achieved an MRD-negative CR had longer median PFS and OS (not reached and 26.5 months) than those who were MRD-positive (12.6 and 10.3 months, respectively). MRD < 0.1% was an independent predictor for CIR, PFS, and OS, after adjusting for European Leukemia Net (ELN) risk, complex karyotype, and transplant (HR 5.92, 95% CI 1.34−26.09, p = 0.019 for PFS; HR 2.60, 95% CI 1.02−6.63, p = 0.046 for OS). Only an MRD threshold of 0.1%, and not 0.01%, was predictive for OS. Our results validate the recommended ELN MRD cut-off of 0.1% to discriminate between patients with improved CIR, PFS, and OS after azacitidine/venetoclax therapy.
Keywords: acute myeloid leukemia; measurable residual disease; venetoclax.