Treatment of relapsed or refractory multiple myeloma in the era of novel agents

The introduction of highly effective novel agents has resulted in a significant improvement in the outcomes of patients with multiple myeloma. These agents, namely thalidomide, bortezomib and lenalidomide, have been extensively studied in the relapsed or refractory multiple myeloma (RRMM) setting and are now being increasingly incorporated into upfront treatment strategies. Second-generation novel agents such as carfilzomib and pomalidomide are being tested in early-phase studies, and preliminary results are encouraging. However, to date, there are no practical guidelines to help physicians choose the best approach for the treatment of RRMM, and direct comparisons between therapies at relapse are warranted. Moreover, despite the recent steps forward in the treatment of multiple myeloma, this disease remains incurable. This article provides an overview of the main studies incorporating novel agents as well as second-generation new drugs for the treatment of RRMM, and may guide physicians in the choice of the most appropriate treatment, associated with prolonged duration of remission and enhanced survival.