The current status and future of multiple myeloma in the clinic

It is now recognized that all cases of multiple myeloma (MM) are preceded by the premalignant condition of monoclonal gammopathy of undetermined significance (MGUS). Although patients with MGUS are generally asymptomatic and currently managed by "watch and wait," the identification of high-risk patients whose disease will progress more rapidly to smoldering MM (SMM) and MM aids in timely intervention. The immunomodulatory agents thalidomide and lenalidomide and the proteasome inhibitor bortezomib are now routine components of MM therapy in both first-line and relapsed/ refractory settings. These targeted agents are used in various combinations with chemotherapy for the treatment of both transplantation-ineligible and transplantation-eligible patients. More recently, a trend toward evaluation of 3- and 4-drug multiagent combinations before transplantation and prolongation of primary therapy has generated new treatment paradigms. Ultimately, the physician's choice of therapy and treatment strategy requires consideration of regimen-associated toxicities and integration of the patient's risk, comorbid status, and response and tolerability of previous treatment regimens. Particular attention needs to be paid to baseline and/or treatment-emergent peripheral neuropathy, thrombotic risk, changes in renal function, and bone health. Despite recent advances, all patients with MM eventually relapse, and efforts to identify novel synergistic combinations and new agents are ongoing. This review highlights challenges in the clinic and newer approaches under evaluation for the treatment and/or management of patients with MGUS, SMM, and MM.