Currently, lenalidomide is considered the standard of care for maintenance in patients with multiple myeloma (MM). However, there is only limited published data on its long-term use concerning the ability to sustain MRD negativity, mechanisms of relapse, and late toxicities. Ola Landgren, MD, PhD, Memorial Sloan Kettering Cancer Center, New York, NY, discusses a study focusing on long-term lenalidomide maintenance therapy in MM patients. The results from this phase II trial reported long-term sustained MRD negativity, and good toxicity and tolerability profiles. Prof. Landgren also reveals that there may be changes in the microenvironment that could potentially be targeted to sustain MRD negativity. This interview took place at the American Society of Hematology (ASH) 2019 Annual Meeting and Exposition in Orlando, FL.