1. Relapsed or refractory B-cell ALL or CML in lymphoid blast phase. Philadelphia chromosome must be present at screening (as determined by cytogenetic analysis, FISH, or PCR [i.e., BCR-ABL positive]). Note: patients with CML who have received treatment with tyrosine kinase inhibitors for their CML, and have progressed to lymphoid blast phase are eligible for frontline treatment. Frontline Ph+ ALL or CML-LBC Cohort: Patients with newly-diagnosed Ph+ ALL or CML-LBC, who have received no or minimal treatment (minimal treatment is defined as treatment with steroids/hydroxyurea of </= 2 week duration; vincristine </= 2 doses; tyrosine kinase inhibitor of </=4 week duration; </=2 doses of cytarabine) and are >/=60 years or older are eligible. Patients must have bone marrow blasts >5% at the time of screening.