Arsenic Trioxide in Treating Patients With Myelodysplastic Syndromes

DISEASE CHARACTERISTICS: * Diagnosis of myelodysplastic syndromes (MDS) * Refractory anemia (RA) * RA with ringed sideroblasts * RA with excess blasts (RAEB) * RAEB in transformation * Chronic myelomonocytic leukemia * Low-risk MDS patients: * If serum erythropoietin less than 200 IU/mL, must have failed prior recombinant epoetin alfa (EPO) trial * No prior acute myeloid leukemia PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * Karnofsky 70-100% Life expectancy: * More than 3 months Hematopoietic: * Not specified Hepatic: * Bilirubin no greater than 2.5 times upper limit of normal (ULN) * SGPT and SGOT no greater than 2.5 times ULN Renal: * Creatinine no greater than 1.5 times ULN Cardiovascular: * Absolute QT interval less than 460 msec in the presence of magnesium greater than 1.8 mg/dL and potassium greater than 4.0 mEq/L Other: * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * See Disease Characteristics * At least 30 days since prior biologic therapy (except recombinant EPO in low-risk MDS patients) Chemotherapy: * Not specified Endocrine therapy: * Not specified Radiotherapy: * At least 30 days since prior radiotherapy Surgery: * Not specified Other: * At least 30 days since prior cytotoxic agents * At least 30 days since prior investigational agents * No prior arsenic trioxide