Maintenance therapy in multiple myeloma.

Despite recent advances, multiple myeloma remains an incurable disease. Induction therapy followed by autologous transplantation has become the standard of care. The idea of maintenance therapy in multiple myeloma is not new. Starting with chemotherapy in 1975, to interferon in 1998, to novel agents recently, a multitude of agents have been explored in patients with multiple myeloma. In spite of the novel agents, multiple myeloma continues to be an incurable disease with the progression-free survival after autologous transplant rarely exceeding 3 years. The goal of using maintenance therapy has been to improve the outcomes following autologous transplantation by increasing the progression-free survival, deepening remissions and perhaps increasing overall survival. It has been shown that patients with a stringent complete response (CR) have a better outcome [Kapoor et al. 2013]. It is becoming increasingly common to check minimal residual disease (MRD) as a means of assessing depth of response. It has also been shown that patients with no MRD have not only a better progression-free survival but also a better overall survival compared with patients who are MRD positive. This makes it even more important to find agents for maintenance therapy, which can further deepen and maintain responses. Here, we present a comprehensive review of the agents studied as maintenance for multiple myeloma and their efficacy, both in terms of overall survival, progression-free survival and toxicity.