Arsenic Trioxide and Imatinib Mesylate in Treating Patients With Chronic Myelogenous Leukemia

DISEASE CHARACTERISTICS: * Cytogenetically confirmed Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia, meeting one of the following criteria: * Chronic phase * Less than 15% blasts in peripheral blood or marrow * Less than 30% blasts and promyelocytes in peripheral blood or marrow * Less than 20% basophils in blood or marrow * Platelet count at least 100,000/mm\^3 (unless therapy related) * No progressive (increase of at least 10 cm in any 4 of the past 24 weeks) or existing (greater than 10 cm) splenomegaly * Complete hematologic response (CHR) * No immature myeloid cells in peripheral blood * No increased basophils in peripheral blood * WBC less than upper limit of normal (ULN) * Platelet count less than ULN * No major (less than 35% Ph+) or complete (0% Ph+) cytogenetic response after at least 6 months of imatinib mesylate * Loss of prior major cytogenetic response or failure to achieve major cytogenetic response PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 Life expectancy * Not specified Hematopoietic * See Disease Characteristics Hepatic * Bilirubin less than 1.5 times ULN * AST or ALT less than 2.5 times ULN Renal * Creatinine less than 1.5 times ULN Cardiovascular * No New York Heart Association grade III or IV congestive heart failure * No untreated symptomatic cardiac ischemia * No underlying cardiac arrhythmia, including but not limited to any of the following: * Conduction abnormality/atrioventricular heart block * Nodal/junctional arrhythmia/dysrhythmia * Sinus bradycardia or tachycardia * Supraventricular tachycardia * Ventricular arrhythmia Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use 2 methods of effective barrier contraception during and for 3 months after study * Electrolyte levels (especially potassium and magnesium) normal (CHR patients) * No history of noncompliance that would preclude study participation * No other concurrent serious, uncontrolled medical condition * No grade 2 or greater neuropathy PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * Not specified Endocrine therapy * Not specified Radiotherapy * Not specified Surgery * Not specified Other * More than 14 days since prior therapy except hydroxyurea, anagrelide hydrochloride, or imatinib mesylate * More than 28 days since prior investigational agents * No concurrent grapefruit or grapefruit juice