Minimal Residual Disease (MRD) in Multiple Myeloma: From Prognostic Marker to Therapeutic Compass.

Multiple myeloma has long been considered incurable; however, advances in therapy have markedly improved outcomes, with a growing proportion of patients achieving sustained remissions suggestive of cure. Minimal (or measurable) residual disease (MRD) has emerged as the most informative biomarker for assessing depth of response and predicting clinical outcomes. Evidence consistently demonstrates that MRD negativity surpasses conventional complete response in prognostic value across disease settings, treatment regimens, and risk groups. Furthermore, MRD has shown potential as a surrogate endpoint for clinical trials and as a tool to guide therapeutic decisions, including treatment intensification, de-escalation, and maintenance strategies. Emerging data also support its relevance in the context of immunotherapy and non-bone marrow-based assessment approaches. Collectively, these findings position MRD as a central component in the evolution toward more precise and individualized management of multiple myeloma.