Arsenic Trioxide and Imatinib Mesylate in Treating Patients With Accelerated Phase or Blastic Phase Chronic Myelogenous Leukemia or Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

DISEASE CHARACTERISTICS: * Diagnosis of one of the following: * Chronic myelogenous leukemia (CML) in one of the following phases: * Blastic phase\* * Accelerated phase\* * No appropriate donors for stem cell transplantation NOTE: \*Must have received high-dose (600-800 mg/day) imatinib mesylate of no more than 3 months duration * Acute lymphoblastic leukemia * Philadelphia chromosome positive by cytogenetic confirmation * Patients with only bcr-abl-positive disease by polymerase chain reaction are not eligible * \> 10% blasts in the bone marrow * No isolated extramedullary disease PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 Life expectancy * Not specified Hematopoietic * Not specified Hepatic * Bilirubin ≤ 2 times upper limit of normal (ULN) * AST ≤ 2 times ULN * INR and PTT ≤ 1.5 times ULN (except for patients on anticoagulation therapy) Renal * Creatinine ≤ 2 times ULN Cardiovascular * Baseline QTc intervals \< 480 ms * No chronic arrhythmias * No active coronary artery disease Other * No chronic electrolyte abnormalities * No prior non-compliance to medical regimens * No patients who are considered potentially unreliable * No active serious infection * No other active malignancies except superficial epithelial cancers * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective barrier contraception during and for at least 3 months after study participation PR…