Newly diagnosed multiple myeloma.

Melphalan combined with prednisone (MP) has been accepted as the standard therapy for previously untreated multiple myeloma (MM) because most studies demonstrate only a modest survival benefit of combination chemotherapy regimens when compared with MP. There have been modest gains with more intensive myeloablative regimens in combination with blood stem cell support, particularly for patients with early primary refractory disease who subsequently achieve partial remission, and for the approximately 25% to 35% of patients achieving complete remission. To preserve the ability to adequately collect stem cells, the use of alkylating agents, such as melphalan, should be limited in the previously untreated patient with myeloma (including those older than 65 years of age) who is a candidate for myeloablative therapy. Pulse dexamethasone-containing regimens provide rapid responses and may be considered the first regimens of choice. Although vincristine/doxorubicin/dexamethasone (VAD) produces responses in approximately 50% to 70% of patients with previously untreated multiple myeloma, use early in the disease has not improved survival. Outside of a specific study protocol, this regimen may be best reserved for patients with refractory (particularly relapsing) disease. Notable exceptions include patients with renal failure or plasma cell leukemia in whom the rapid responses provided by VAD may avoid potentially permanent, serious complications. Recently, new agents with novel mechanisms of action (ie, thalidomide, immunomodulatory drugs, proteosome inhibitors) have demonstrated activity in resistant myeloma. Because these agents are likely to show activity alone or in combination, newly diagnosed patients and previously untreated patients should be considered for clinical trials. Thalidomide/dexamethasone has already produced response rates of 65% to 75% in previously untreated patients. Its ease of administration along with stem cell preservation are likely to make this, followed by myeloablative therapy with stem cell support, the treatment of choice for untreated myeloma as confirmatory studies are completed.