Maintenance therapy for multiple myeloma in the era of novel agents

Despite many recent advances in the treatment of multiple myeloma, the course of the disease is characterized by a repeating pattern of periods of remission and relapse as patients cycle through the available treatment options. Evidence is mounting that long-term maintenance therapy may help suppress residual disease after definitive therapy, prolonging remission and delaying relapse. For patients undergoing autologous stem cell transplantation (ASCT), lenalidomide maintenance therapy has been shown to improve progression-free survival (PFS); however, it is still unclear whether this translates into extended overall survival (OS). For patients ineligible for ASCT, continuous therapy with lenalidomide and low-dose dexamethasone was shown to improve PFS and OS (interim analysis) compared with a standard, fixed-duration regimen of melphalan, prednisone, and thalidomide in a large phase 3 trial. Other trials have also investigated thalidomide and bortezomib maintenance for ASCT patients, and both agents have been evaluated as continuous therapy for those who are ASCT ineligible. However, some important questions regarding the optimal regimen and duration of therapy must be answered by prospective clinical trials before maintenance therapy, and continuous therapy should be considered routine practice. This article reviews the available data on the use of maintenance or continuous therapy strategies and highlights ongoing trials that will help to further define the role of these strategies in the management of patients with newly diagnosed multiple myeloma.