Study of the Glutaminase Inhibitor CB-839 in Leukemia

Inclusion Criteria * Diagnosis of AML or ALL, relapsed or refractory after at least 1 prior treatment regimen. Newly-diagnosed patients ≥ 60 years old who have refused or are considered unfit for standard chemotherapy regimens or stem cell transplantation are also eligible. * Patients must have no available approved therapies that confer clinical benefit * All patients must have bone marrow involvement of their tumor, with documented blast percentage of \> 5%. * Peripheral blood blast count must be ≤ 30,000 cells/µL. * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2 * Adequate hepatic, renal, and cardiac function Exclusion Criteria * Any other current malignancy * Patients with acute promyelocytic leukemia (APL) * Treatment with an unapproved, investigational agent within 21 days of the first dose of study drug * Allogeneic hematopoietic stem cell transplant or Donor Lymphocyte Infusion within 90 days prior to to the first dose of study drug * Active GVHD * Unable to receive medications by mouth * Major surgery within 28 days before Cycle 1 Day 1 * Uncontrolled, active infection; patients who are known to have HIV infection/ seropositivity, Hepatitis A, B, or C, or CMV reactivation * Significant neurotoxicity/neuropathy (Grade 3 or higher) within 14 days prior to Day 1 * Refractory nausea and vomiting or other situation that may preclude adequate absorption * Conditions that could interfere with treatment and procedures