Novel therapies in multiple myeloma.

The discovery of the activity of thalidomide in myeloma in the late 1990s transformed the therapy of myeloma dramatically. Apart from providing a useful treatment option for patients with myeloma, it has spurred clinical investigation of several other nonchemotherapeutic agents for this disease. These active, promising agents include CC-5013 (a thalidomide analog) and bortezomib (a proteasome inhibitor), as well as other agents, such as arsenic trioxide, ENMD 0995 and 2-methoxyestradiol. Preliminary data show that a number of these agents are active in treating disease that has relapsed after conventional chemotherapy as well as after high-dose therapy and transplantation, and some agents are active even after other novel agents have failed. The only novel drug that is commercially available currently is thalidomide, which has a therapeutically relevant benefit at all stages of the disease. A therapeutic trial of thalidomide is essential for all patients with myeloma. There are in vitro and in vivo data showing synergy between some of the novel agents. Although these novel drugs are typically used for treating disease that is refractory to or has relapsed after cytotoxic therapy, it is likely that they will start being used as part of frontline therapy, either by themselves or in combination with chemotherapy.