The Role of Minimal Residual Disease (MRD) in Predicting Relapse in Acute Leukemia

Minimal residual disease (MRD) is a relatively newly established biomarker that enables clinicians to clinically assess and manage acute leukemia. Induction therapy eradicates leukemia cells in the peripheral blood; nonetheless, a considerable proportion of patients with acute lymphoblastic leukemia or acute myeloid leukemia persist in harboring leukemia cells that remain undetectable by standard microscopy. Real-time quantitative polymerase chain reaction, multiparameter flow cytometry, and next-generation sequencing are approaches utilized for assessing MRD. Although the declaration of MRD can vary depending on detection methodologies, MRD status has shown a significant association to relapse risk and overall survival, outperforming any standard risk factor. Evaluating MRD status at key timepoints (post-induction therapy, postconsolidation therapy, and pre-transplant) provides the basis for risk-adapted therapies, the timing of further consolidative therapies, and guiding decisions for hematopoietic stem cell transplant. Though many clinical centers routinely assess MRD status in the acute leukemia clinical setting, there are various challenges, such as variability between assays, technical aspects of certain MRD assessments, and no clear standard for MRD assessment and reporting. Despite these challenges, recent advancements in technology have improved performance and standardization of assays. recently, a number of clinical trials have involved MRD in supporting response-adapted treatment regimens. With an increased focus on genetic and immunologic risk both from MRD and other markers of disease response, MRD can guide us toward a more generalized approach to leukemia management. This review outlines the biological basis and clinical significance of MRD in the context of leukemia management and highlights the future innovations in MRD assessment