Arsenic Trioxide in Treating Patients With Multiple Myeloma

DISEASE CHARACTERISTICS: Diagnosis of multiple myeloma Stage II or III (Durie-Salmon) Relapsed or refractory to conventional therapy No monoclonal gammopathy or indolent or smoldering myeloma Measurable disease by serum and urine M protein and/or plasmacytoma PATIENT CHARACTERISTICS: Age: Over 18 Performance status: Karnofsky 70-100% Life expectancy: 3 months Hematopoietic: Granulocyte count greater than 1,200/mm3 Platelet count greater than 100,000/mm3 Hemoglobin greater than 10 g/dL Hepatic: Bilirubin less than 2 times upper limit of normal (ULN) SGOT/SGPT less than 2 times ULN Renal: Creatinine no greater than 2.5 mg/dL Cardiovascular: Absolute QT interval less than 460 msec in the presence of normal potassium and magnesium levels PRIOR CONCURRENT THERAPY: Biologic therapy: At least 28 days since prior biologic therapy Chemotherapy: No more than 3 prior chemotherapy regimens, including no more than 2 cytotoxic regimens AND 1 high-dose cytotoxic regimen as part of stem cell transplantation Endocrine therapy: At least 28 days since prior endocrine therapy Radiotherapy: At least 28 days since prior radiotherapy (except for focal radiotherapy for symptom control) Surgery: Not specified