Contemporary drug therapies for multiple myeloma

Multiple myeloma (MM) is an incurable disease characterized by the proliferation of plasma cells. The survival in MM patients has improved significantly in the past decade due to the introduction of novel agents. In this review, we focus on novel agents used in MM, including immunomodulatory drugs (thalidomide, lenalidomide and pomalidomide), proteasome inhibitors (bortezomib, carfilzomib, marizomib and ixazomib citrate), monoclonal antibodies (elotuzumab, siltuximab, daratumumab and BT-062), and drugs affecting an interaction with the tumor microenvironment (anti-VLA4 monoclonal antibody, chemokine CXCR4 inhibitor AMD-3100 and selectin inhibitor CMI-1070). We discuss their mechanism of action, preclinical and clinical outcome in the treatment of MM. Although the development of novel agents has improved the outcomes of MM treatment, most of the patients will still relapse and become refractory to therapy due to development of drug resistance. A better understanding of the biological mechanisms of MM progression, including cellular and molecular events in the MM cells and in their bone marrow microenvironment, is warranted to provide new therapeutic targets and develop new drugs and therapeutic strategies to treat MM.