Measurable Residual Disease Assessment in Multiple Myeloma: How Deep Is Enough?

The introduction of new and more effective therapeutic options for Multiple Myeloma (MM) has significantly deepened and prolonged patients’ remission. As currently used treatment protocols induce high rates of complete responses, Measurable Residual Disease (MRD) assessment has become essential to enhance the evaluation of treatment efficacy. Detection of MRD has improved with the development of highly sensitive and standardized techniques such as Next Generation Flow or Next Generation Sequencing, complemented by functional imaging techniques. These advances offer a valuable opportunity to further optimize criteria of response to treatment. Currently, extensive data demonstrate that MRD status is a valuable prognostic factor of survival. Since MRD represents a real measurement of disease burden, its incorporation in clinical trials to guide treatment decisions will certainly translate into clinical benefits. Sustained MRD negativity can be used to consider optimal candidates for treatment discontinuation, whereas MRD positive high-risk patients may have access to novel immunotherapeutic strategies such as bispecific drugs or CAR T cell therapy. In this review, we describe the available techniques to detect MRD, address the current data regarding MRD as a surrogate endpoint within clinical trials, examine how MRD can be introduced into the clinical management of MM patients, and discuss the future of MRD monitoring.