This study will evaluate MK0457 in patients with chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia. Efficacy and safety will be evaluated.

Inclusion Criteria:

• This study will evaluate MK0457 in patients with CML (chronic myelogenous leukemia) and Ph+ALL (Philadelphia chromosome-positive acute lymphoblastic leukemia)
• Patients must have adequate organ function
• Patients must have documented T315I mutation

Exclusion Criteria:

• Patients within 3 months of allogeneic bone marrow transplant or not fully recovered from previous anti-leukemia therapy
• Patients with uncontrolled congestive heart failure
• Patients with active or uncontrolled infection or active Hepatitis B or C
• Patients with known HIV positivity or AIDS related illness
• Patients with currently active second malignancy, other than non-melanoma skin cancer.