Inclusion criteria:

• For Arm A Part 1 (monotherapy/dose escalation): refractory or recurrent AML, not an appropriate candidate for standard therapy
• For Arm A Part 2 (monotherapy/dose confirmation/cohort expansion): refractory or recurrent AML, not an appropriate candidate for standard therapy, and have wild type TP53 gene mutation analysis
• For Arm B Part 1 (combination therapy/dose escalation): recurrent AML having achieved an initial CR or CRi of 6-12 months duration and age ≥18 years old and <70 years old
• For Arm B Part 2 (combination therapy/dose confirmation/cohort expansion): recurrent AML having achieved an initial CR or CRi of 6-12 months duration, age ≥18 years old and <70 years old, and have wild type TP53 gene mutation analysis
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 for all Arm A, or 0 or 1 for all Arm B
• Negative pregnancy test within 72 hours of the first dose of study medication
• Female participants and male participants and their partners who are of childbearing potential must agree to abstain from sexual intercourse or to use an acceptable method of contraception during the study and for 90 days following the last dose of study therapy
• Adequate organ function
• Recovered from the effects of any prior surgery, radiotherapy or anti-neoplastic treatment, with the exception of alopecia
• Must be able to swallow, retain, and absorb oral medications and oral nutrition
• Must follow the appropriate washout period for prohibited treatments

Exclusion criteria:

• Active malignancy other than AML
• Leptomeningeal leukemia requiring intrathecal therapy
• For Arm A and B, Part 1 only: history of myelodysplastic syndrome (MDS)
• For Arm A and B, Part 2: AML in the background of MDS may be included
• Isolated extramedullary leukemia without also meeting bone marrow criteria for acute leukemia
• AML blast crisis of chronic myelogenous leukemia (CML)
• Bone marrow transplant with active graft-versus host disease (GVHD) or who receives immunosuppressive therapy
• Uncontrolled active infection that requires systemic treatment
• Clinically significant hepatitis at Screening, or hepatitis C antibody positive, hepatitis B surface antigen positive, or human immunodeficiency virus (HIV) seropositive
• Persistent, unresolved, drug-related toxicity
• Breast-feeding, pregnant, intends to become pregnant or intends to breast feed during the study or has a positive pregnancy test at Screening
• A person participating in any other clinical study with a potentially therapeutic agent or who has received another investigational product within 5 half-lives (if the half-life is known) or 28 days (if the half-life is unknown) prior to Day 1 of cycle 1
• A participant who, within the past 6 months, has had any of the following: myocardial infarction, coronary/peripheral artery bypass graft, cerebrovascular accident, transient ischemic attack, or uncontrolled seizure disorder (i.e., seizures within the past 6 months)
• A participant who, at the time of Screening, presents with: unstable or uncontrolled angina, New York Heart Association (NYHA) class III or IV congestive heart failure, uncontrolled hypertension, clinically significant cardiac dysrhythmia or clinically significant electrocardiogram (ECG) abnormality
• Known bleeding disorder, e.g. hemophilia or disseminated intravascular coagulopathy or on anti-coagulation therapy
• For Arm B only: Known hypersensitivity to cytarabine