Multiple myeloma: an old disease with new hope for the future.

Multiple myeloma is a currently incurable malignancy of terminally differentiated plasma cells. It typically occurs in older patients (median age 71 years). Clinical manifestations result from monoclonal protein (immunoglobulin) production and its accumulation in the serum and/or urine, anemia, lytic bone disease, hypercalcemia, renal insufficiency, and immune deficiency. Myeloma cells have low proliferative activity--most myeloma experts opine that the initial oncogenic event occurs 10-15 years before clinical disease manifestation. In addition, myeloma cells develop multiple chromosomal abnormalities, which may explain the native resistance of myeloma patients to conventional therapy and our inability to completely eradicate the disease. Indeed, with conventional therapy, only 5% of patients achieve complete response. Minimal improvement has been observed with conventional therapies over the past 20-30 years; the median duration of initial response remains approximately 18 months with median survival in the 36-month range. However, recent clinical trials have established high-dose therapy with autologous hematopoietic stem cell transplant as superior to conventional therapy: complete remission rates of 25-30% can be affected with median survival exceeding 5 years. Newer approaches to improve treatment outcomes are in active clinical trials including: more potent induction regimens utilizing thalidomide, alone or in combination with dexamethasone; tandem transplants to improve complete remission rates; newer approaches to maintenance therapy using thalidomide with corticosteroids; non-myeloablative therapy with allogeneic transplant; and post-transplant vaccinations.