Inclusion Criteria:

- Patients must have chronic myelogenous leukemia (CML) or Philadelphia
chromosome-positive acute lymphoblastic leukemia (Ph+ ALL)

- Patients must be at least 3 months from the start of dasatinib therapy and are
currently receiving dasatinib therapy for CML or Ph+ ALL and be evaluable for
hematologic response prior to entering the study

- Patient is able to be treated with a 70 mg bid dose of dasatinib without significant
toxicity at the time of study entry

- Patients with active CNS disease are included and may be treated concurrently with
intrathecal therapy as per institutional standards

Exclusion Criteria:

- Patient has had treatment with any anti-leukemia therapy (investigational or
approved) other than dasatinib during the preceding 3 months. Pheresis or hydroxyurea
treatment in the preceding 3 months will not exclude patients from eligibility

- Patient has unresolved more than or equal to grade 2 clinically significant toxicity
attributed to dasatinib at the time of study entry

- Patient has known hypersensitivity to the components of study drug or its analogs

- Patient is pregnant or breastfeeding, or expecting to conceive within the projected
duration of the study

- Patient has symptomatic ascites, pericardial or pleural effusion. A patient who is
clinically stable following treatment for these conditions is eligible

- Patient has had prior radiation therapy to more than 10% of the bone marrow; patients
must have recovered for at least 3 weeks from the hematologic toxicity of prior
radiotherapy

- Patient has a LVEF <40% by multigated radionucleotide angiography (MUGA) or
echocardiography