Omacetaxine and Venetoclax for the Treatment of Relapsed or Refractory Acute Myeloid Leukemia or Myelodysplastic Syndrome Harboring Mutant RUNX1

PRIMARY OBJECTIVES: I. To determine the safety and tolerability and recommended phase 2 dose (RP2D) of omacetaxine in combination with venetoclax for patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome harboring a RUNX1 mutation. (Phase 1b) II. To determine the efficacy of omacetaxine in combination with venetoclax for patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome harboring a RUNX1 mutation. (Phase II) SECONDARY OBJECTIVES: I. To determine duration of response (DOR), event-free survival (EFS), and overall survival (OS). II. To evaluate occurrence of minimal residual disease (MRD) negative status by multiparameter flow cytometry and molecular evaluation. OUTLINE: This is a phase I, dose de-escalation study followed by a phase II study. Patients receive omacetaxine subcutaneously (SC) twice daily (BID) on days 2-3 or 2-4, and venetoclax orally (PO) on days 1-7, 1-10 or 1-14. Treatment repeats every 28 days for up to 12 cycles in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up within 30 days, then every 3 months for 3 years.