Sequential High-Dose Melphalan and Busulfan/Cyclophosphamide Followed by Peripheral Blood Progenitor Cell Rescue, Interferon/Thalidomide and Pamidronate for Patients With Multiple Myeloma

OBJECTIVES: Determine the feasibility and toxic effects of high-dose melphalan, busulfan, and cyclophosphamide followed by autologous peripheral blood stem cell rescue, interferon alfa, and pamidronate in patients with responsive or stable, low-bulk multiple myeloma. Determine the response rate and progression-free and overall survival of patients treated with this regimen. Determine the feasibility of adding thalidomide to interferon alfa and pamidronate in patients who are not in complete remission (CR) 6 months after the second course of high-dose chemotherapy. Determine whether administration of thalidomide can increase the CR rate in patients who are not in CR 6 months after the second course of high-dose chemotherapy and determine its effect on progression-free and overall survival of these patients. Determine the pharmacokinetics of busulfan and cyclophosphamide and correlate the pharmacokinetics with the toxic effects of these drugs and outcome in these patients. Determine the effect of thalidomide on microvascular density of bone marrow and correlate these possible effects with outcome in these patients. Determine the cytogenetics, gene rearrangement, and fluorescence in situ hybridization in baseline and post treatment bone marrow and blood specimens and correlate the presence/persistence of these features with treatment outcome in these patients. OUTLINE: Patients receive cyclophosphamide IV over 2 hours on day 1 and filgrastim (G-CSF) subcutaneously (SC) or IV twice a day beginning on day 2 and continuing until peripheral blood stem cells (PBSCs) are collected. PBSCs are collected beginning on day 10. Patients receive high-dose melphalan IV on day -1. PBSCs are reinfused on day 0. G-CSF is administered IV or SC daily beginning on day 1 and continuing until blood counts recover. Between 8 and 14 weeks later, patients receive high-dose busulfan IV every 6 hours on days -7 to -4 and cyclophosphamide IV over 2 hours on days -3 and -2. PBSCs are reinfused on day 0 and G-CSF is administered IV or SC daily until blood counts recover. Patients with responding or stable disease after chemotherapy receive maintenance therapy with interferon alfa beginning 14-20 weeks after day 0 of the second course of chemotherapy. Interferon alfa is administered SC 3 times a week for 3 years. Patients also receive pamidronate IV every 4 weeks until disease progression. Patients who are not in complete remission (CR) 6 months after completing the second course of chemotherapy receive oral thalidomide daily for a maximum of 1 year or for 3 months after achieving CR. Patients are followed monthly for 1 year, every 3 months for 1 year, and then periodically thereafter. PROJECTED ACCRUAL: A total of 70 patients will be accrued for this study within approximately 2.5 years.