RATIONALE: High-dose chemotherapy may destroy the amyloid-producing cells in bone marrow. Peripheral stem cell transplantation

PURPOSE: Phase II trial to study the effectiveness of high dose melphalan plus peripheral stem cell transplantation in treating patients who have primary systemic amyloidosis.

OBJECTIVES: I. Assess the response rate and overall survival of patients with biopsy proven primary amyloidosis following treatment with myeloablative chemotherapy and hematopoietic stem cell reconstitution. II. Evaluate the toxicity of high dose melphalan in this patient population.

OUTLINE: Patients receive filgrastim (G-CSF) subcutaneously daily beginning on day 1 of the peripheral blood stem cell (PBSC) collection period and continuing until PBSC collection is completed. PBSC are collected beginning on day 5 of the collection period and continuing until the final target cell count is reached or for up to a maximum of 7 collections. If sufficient PBSCs are not harvested within a maximum of 7 collections, the patient is removed from the study. Within 30 days of PBSC collection, patients receive melphalan IV on day -1 of the infusion period and PBSC infusion on day 0. The infusion period continues until day 30. Patients receive G-CSF subcutaneously daily starting on day 1 and continuing until blood counts recover. Patients are followed every 3 months for 2 years, every 3 months for 3 additional years, and yearly thereafter.

PROJECTED ACCRUAL: A maximum of 33 patients will be accrued for this study over 2 years.

DISEASE CHARACTERISTICS: Histologically confirmed primary amyloidosis Must have presence of paraprotein in serum or urine determined by immunoelectrophoresis/immunofixation No primary amyloidosis manifested only by carpal tunnel syndrome or purpura No history of secondary, familial, or localized amyloidosis No evidence of overt multiple myeloma: Lytic bone disease or pathological fractures OR At least 30% plasma cells in bone marrow

PATIENT CHARACTERISTICS: Age: 18 to 70 Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Absolute granulocyte count at least 1000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 2.0 mg/dL Alkaline phosphatase no greater than 1000 u/L or less than 4 times upper limit of normal Renal: Creatinine no greater than 2.0 mg/dL Cardiovascular: Confirmed by echocardiogram: Ejection fraction at least 50% Interventricular septal thickness no greater than 15 mm No New York Heart Association classification II-IV Pulmonary: DLCO at least 50% FVC at least 60% FEV1 at least 55% Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No active infection No other malignancy within the past 5 years except surgically treated carcinoma in situ of the cervix, nonmelanoma skin cancer, or indolent prostate cancer No known sensitivity to E. coli derivatives

PRIOR CONCURRENT THERAPY: Biologic therapy: Prior interferon allowed Chemotherapy: At least 4 weeks since prior melphalan Lifetime cumulative dose of melphalan no greater than 150 mg No greater than 2 prior courses of chemotherapy Endocrine therapy: Prior dexamethasone allowed Radiotherapy: Not specified Surgery: Not specified