Myeloma Minimal Residual Disease and Surrogacy

To the Editor We commend Munshi and colleagues¹ for their excellent article demonstrating the prognostic value of minimal residual disease (MRD) in multiple myeloma (MM). We agree that these results support MRD as a clinically useful tool for patient management and treatment development. However, we disagree with the authors’ conclusion that these results support the use of MRD as a surrogate end point for long-term clinical outcomes in randomized clinical trials (RCTs).