An Open-Label, Multicenter, Phase 1b/2 Study of the Safety and Efficacy of KRT-232 When Administered Alone and in Combination With Low-Dose Cytarabine (LDAC) or Decitabine in Patients With Acute Myeloid Leukemia (AML)

Key Inclusion Criteria: * Part A: Patients with relapsed or refractory AML, or newly-diagnosed AML secondary to MPN * Part B:Patients with relapsed or refractory AML secondary to MPN (myelofibrosis \[MF\], polycythemia vera \[PV\], or essential thrombocythemia \[ET\]); patients may have been treated with ≥1 prior lines of therapy for their AML secondary to MPN. * Adequate hepatic and renal function * Appropriate prior treatment with an FLT3 or IDH1/2 inhibitor where applicable Key Exclusion Criteria: * Patients who are TP53 mutation positive * Prior treatment with an MDM2 antagonist therapy * Patients treated with ≥ 18 g/m2 of cytarabine within the prior 90 days are not eligible to be treated with cytarabine on this study but may be treated with decitabine (for Part A) . * Patients previously treated with decitabine are not eligible to receive decitabine on this study but may be treated with cytarabine (for Part A) . * Patients who have received an allogeneic HSCT within 90 days of enrollment or who have active graft-versus-host disease requiring active therapy (for Part A) * Allogeneic stem cell transplant within 3 months; autologous stem cell transplant within 3 months or active graft-versus-host disease prior to first dose of study treatment (for Part B) * Patients who have received immunosuppressive therapy for graft-versus-host disease within 1 month prior to enrollment into this study * Patients who are eligible for an allogeneic HSCT per the opinion of the investigator and have a donor. Patients who are HSCT-eligible in the opinion of the investigator, but who refuse a transplant, are eligible for the study. * Patients with known CNS involvement with AML, acute promyelocytic leukemia (APL), or a history of bleeding diathesis * Patients who have had major surgery within 28 days prior to the first treatment with KRT-232 * Women who are pregnant or breastfeeding