PRIMARY OBJECTIVES:~I. To compare response rate, time to response, duration of response, toxicity, and survival in the two regimens (vincristine sulfate, carmustine, melphalan, cyclophosphamide, prednisone [VBMCP] vs. VBMCP alternating with high-dose cyclophosphamide and then with recombinant interferon alfa-2b [r alpha2b-IFN]) in patients with previously untreated multiple myeloma.~II. To determine the value of the ancillary laboratory studies to predict response and survival.~OUTLINE:~INDUCTION PHASE: Patients receive VBMCP comprising vincristine sulfate intravenously (IV) on day 1, carmustine IV on day 1, melphalan orally (PO) on days 1-4, cyclophosphamide IV on day 1, and prednisone PO on days 1-7. Treatment repeats every 35 days for 2 courses in the absence of disease progression or unacceptable toxicity.~CONSOLIDATION PHASE: Patients are randomized to 1 of 2 treatment arms.~ARM A: Patients receive VBMCP as in the induction phase. Courses repeat every 35 days in the absence of disease progression or unacceptable toxicity.~ARM B: Patients receive vincristine sulfate, carmustine, and melphalan as in the induction phase, high-dose cyclophosphamide IV on days 1-4 and prednisone PO on days 1-4 during courses 3 and 5. Patients receive VBMCP as in the induction phase during even numbered courses. Patients receive recombinant interferon alfa-2b subcutaneously (SC) on days 1, 3, 5, 8, 10, 12, 15, 17, 19, and 22 during odd courses beginning course 7. Treatment repeats every 35 days for courses 3-5, every 21 days for even courses beginning course 6, and every 22 days for odd courses beginning course 7 in the absence of disease progression or unacceptable toxicity.~In both arms, treatment continues for up to 2 years.~After completion of study treatment, patients are followed up for 1 year.
This randomized phase III clinical trial studies combination chemotherapy with high dose cyclophosphamide and recombinant interferon alfa-2b to see how well it works compared to combination chemotherapy alone in treating patients with previously untreated stage I-III multiple myeloma. Drugs used in chemotherapy, such as vincristine sulfate, carmustine, melphalan, cyclophosphamide, and prednisone, work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Recombinant interferon alfa-2b may interfere with the growth of cancer cells. It is not yet know whether giving combination chemotherapy with or without alternating high-dose cyclophosphamide and recombinant interferon alfa-2b is more effective in treating multiple myeloma.