Role of MRD status in relation to clinical outcomes in newly diagnosed multiple myeloma patients: a meta-analysis.

Driven by access to better drugs, on average, newly diagnosed multiple myeloma patients have over 10 years overall survival. Using modern combination therapies-with or without the addition of high-dose melphalan and autologous stem cell transplantation-up to 80% of patients reach a complete response. As a logical and necessary step forward, clinical studies have explored strategies to detect minimal residual disease (MRD) and its correlation with clinical outcomes. In this context, MRD has been proposed as a regulatory end point for drug approval in newly diagnosed multiple myeloma. To better define the role of MRD negativity in relation to clinical outcomes, we undertook a meta-analysis including published clinical trials of newly diagnosed multiple myeloma patients. We applied a random effects model which weighted studies using the inverse-variance method. Studies were combined on the scale of the logarithm of the hazard ratio (HR) and the corresponding s.d. We found that MRD negativity (versus positivity) was associated with better PFS (HR=0.35; 95% confidence interval (CI) 0.27-0.46; P<0.001) and overall survival (HR=0.48; 95% CI 0.33-0.70; P<0.001). Our results show that MRD negativity is a strong predictor of clinical outcomes, supportive of MRD becoming a regulatory end point for drug approval in newly diagnosed multiple myeloma.