Clinical impact of measurable residual disease monitoring by ultradeep next generation sequencing in <i>NPM1</i> mutated acute myeloid leukemia

Abstract

Detection of measurable residual disease (MRD) by mutation specific techniques has prognostic relevance in <i>NPM1</i> mutated AML (<i>NPM1</i> ^mut AML). However, the clinical utility of next generation sequencing (NGS) to detect MRD in AML remains unproven. We analysed the clinical significance of monitoring MRD using ultradeep NGS (NGS-MRD) and flow cytometry (FCM-MRD) in 137 samples obtained from 83 patients of <i>NPM1</i> ^mut AML at the end of induction (PI) and consolidation (PC). We could monitor 12 different types of <i>NPM1</i> mutations at a sensitivity of 0.001% using NGS-MRD. We demonstrated a significant correlation between NGS-MRD and real time quantitative PCR (RQ-PCR). Based upon a one log reduction between PI and PC time points we could classify patients as NGS-MRD positive (<1log reduction) or negative (>1log reduction). NGS-MRD, FCM-MRD as well as <i>DNMT3A</i> mutations were predictive of inferior overall survival (OS) and relapse free survival (RFS). On a multivariate analysis NGS-MRD emerged as an independent, most important prognostic factor predictive of inferior OS (hazard ratio, 3.64; 95% confidence interval [CI] 1.58 to 8.37) and RFS (hazard ratio, 4.8; 95% CI:2.24 to 10.28). We establish that DNA based <i>NPM1</i> NGS MRD is a highly useful test for prediction of relapse and survival in <i>NPM1</i> ^mut AML.