Amifostine and Melphalan in Treating Patients With Primary Systemic Amyloidosis Who Are Undergoing Peripheral Stem Cell Transplantation

DISEASE CHARACTERISTICS: Histologically confirmed amyloidosis No secondary familial or localized amyloidosis Presence of monoclonal protein by immunoelectrophoresis or immunofixation of serum or urine No primary amyloidosis manifested only by carpal tunnel syndrome or purpura Amyloid deposits in a plasmacytoma or in bone marrow vessels in an asymptomatic individual not considered an amyloid syndrome Amyloid syndromes include any of the following: Hepatomegaly Cardiomyopathy Nephrotic range proteinuria Peripheral or autonomic neuropathy No multiple myeloma defined by 1 of the following: Presence of lytic bone disease More than 30% bone marrow plasma cells PATIENT CHARACTERISTICS: Age 18 to 70 Performance status ECOG 0-1 Life expectancy Not specified Hematopoietic Platelet count at least 100,000/mm^3 Hepatic See Disease Characteristics Total or direct bilirubin no greater than 2.0 mg/dL Alkaline phosphatase no greater than 4 times upper limit of normal Renal See Disease Characteristics Creatinine less than 3.0 mg/dL Cardiovascular See Disease Characteristics Ejection fraction at least 45% by echocardiogram No New York Heart Association class III or IV heart disease Systolic blood pressure ≥ 90 mmHg 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 PRIOR CONCURRENT THERAPY: Biologic therapy At least 4 weeks since prior interferon Chemotherapy At least 4 weeks since prior melphalan Lifetime total melphalan dose less than 150 mg/m^2 (based on ideal body weight) Endocrine therapy At least 4 weeks since prior dexamethasone Radiotherapy No prior radiotherapy for amyloidosis Surgery Not specified Other No antihypertensive medications for at least 24 hours prior to, during, and for 1 hour after amifostine administration No other prior treatment