Concordance of Next-Generation Sequencing and Multiparametric Flow Cytometry Methods for Detecting Measurable Residual Disease in Adult Acute Lymphoblastic Leukemia: Optimizing Prediction of Clinical Outcomes From a Single-Center Study

This is a retrospective study of acute lymphoblastic leukemia patients with available next -generation sequencing (NGS) reports at our institution. Using NGS, we found low levels of detectable disease in patients who were negative on multiparametric flow cytometry (MFC). These NGS + /MFC- individuals had higher relapse rates than those who were NGS-/MFC-, indicating the utility of NGS in risk stratification. Introduction: Detection of measurable residual disease (MRD) in adults with acute lymphoblastic leukemia (ALL) is a vital biomarker in risk prediction and treatment selection. Next -generation sequencing (NGS) offers greater sensitivity relative to multiparametric flow cytometry (MFC) and may be a better predictive tool for identifying ALL patients at risk of relapse. Patients and Methods: This single -center retrospective study compares MRD detection by NGS versus MFC in 52 adult B- and T -ALL patients treated at our institution between 2018 and 2023. Pretreatment bone marrow samples were used for assay calibration, while post -treatment MRD assessment was completed up to 4.5 months after the first complete remission (CR1) using an MRD cutoff of 10-6 for distinguishing relapse risk. Results: The 2 -year cumulative incidence of relapse (CIR) among patients who were MRD positive using MFC and NGS was 39.5% and 46.2%, respectively. Unlike MFC, post-CR1 MRD positivity with NGS significantly predicted CIR (HR = 9.47, P = .028). In patients who were MRD negative by MFC, low levels of MRD detected by NGS distinguished patients at high risk of relapse (HR 10.3, P = .026, 2 -year CIR 51.6%). Conclusion: Our data suggests that assessment of post-CR1 MRD using a highly sensitive NGS assay can identify ALL patients undergoing frontline therapy at increased risk of relapse and guide the use of adjuvant therapy.