Chemotherapy Plus Steroid Therapy in Treating Patients With Multiple Myeloma

DISEASE CHARACTERISTICS: Diagnosis of multiple myeloma based on at least two of the following: Paraprotein in serum and/or urine Greater than 10% plasma cells in bone marrow Lytic bone lesions Measurable serum and/or urine paraprotein Progression from first or second stable plateau phase No non-secretory myeloma or plasma cell leukemia (greater than 2,000/mm^3 circulating plasma cells) No primary refractory disease or second or later relapse PATIENT CHARACTERISTICS: Age: 18 and over Performance status: 0-3 Life expectancy: Not specified Hematopoietic: Neutrophil count at least 1,000/mm^3 Platelet count at least 75,000/mm^3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) ALT/AST no greater than 2.5 times ULN Renal: Creatinine less than 3.4 mg/dL Cardiovascular: No clinically significant cardiac insufficiency No uncontrolled hypertension Other: No uncontrolled diabetes mellitus No recent history of peptic ulceration HIV-1 and HIV-2 negative Fertile patients must use effective contraception during and for 6 months after study participation PRIOR CONCURRENT THERAPY: Biologic therapy: No prior allogeneic peripheral blood stem cell or bone marrow transplantation No planned future autologous transplantation unless sufficient stored stem cells available Prior interferon allowed if administered as maintenance of stable plateau phase No concurrent epoetin alfa Chemotherapy: At least 3 months since prior chemotherapy Endocrine therapy: Not specified Radiotherapy: Concurrent radiotherapy for pain or to treat localized tumors allowed Surgery: Not specified Other: No prior participation in any clinical trial with an unlicensed product