CPI-613 Given With Metformin in Patients With Relapsed or Refractory Acute Myeloid Leukemia (AML)

Inclusion Criteria: * Patients must have histologically or cytologically documented relapsed and/or refractory Acute Myeloid Leukemia or granulocytic sarcoma. * Eastern Cooperative Oncology Group (ECOG) Performance Status of ≤ 3. * Must be ≥ 18 years of age. * Persons of child-bearing potential (i.e., women who are pre-menopausal or not surgically sterile) must use accepted contraceptive methods (abstinence, intrauterine device \[IUD\], oral contraceptive or double barrier device), and must have a negative serum or urine pregnancy test within 1 week prior to treatment initiation. * Persons who are having sexual relationships in which their partner may become pregnant must practice effective contraceptive methods during the study treatment and for 60 days after the last dose of study treatment, unless documentation of infertility exists. * Mentally competent, ability to understand and willingness to sign the informed consent form. * Patients with persisting, non-hematologic, non-infectious toxicities from prior treatment must be ≤ Grade 2 and must be documented as such. * Laboratory values ≤ 2 weeks prior to the start of study treatment must be the following: * Aspartate aminotransferase \[AST/SGOT\] ≤ 5x upper normal limit \[UNL\], * Alanine aminotransferase \[ALT/SGPT\] ≤ 5x UNL * Bilirubin ≤ 3x UNL * Albumin ≥ 2.0 g/dL or ≥ 20 g/L * Serum creatinine ≤ 2.0 mg/dL * Presence of central venous catheter or willing to have central venous access placed. Exclusion Criteria: * Patients with active central nervous system (CNS) or epidural tumor. * Pregnant persons, or persons of child-bearing potential not using reliable means of contraception (because the teratogenic potential of CPI-613 is unknown). * Breastfeeding individuals because the potential of excretion of CPI-613 into breast milk. (Note: Breastfeeding individuals are excluded because the effects of CPI-613 on a nursing child are unknown). * Any condition or abnormality which may, in the opinion of the investigator, compromise the safety of patient. * Unwilling or unable to follow protocol requirements. * Patients receiving any other standard or investigational treatment for their cancer, or any other investigational agent for any indication within the past 1 week prior to initiation of CPI-613 treatment with the following exceptions: * The use of Hydrea or any targeted oral agent is allowed up to the day before initiation of treatment.