A Phase 1/2, Open-label, Multicenter Trial to Assess the Safety and Efficacy of ARD103 in Patients With Relapsed or Refractory Acute Myeloid Leukemia or Myelodysplastic Syndrome

Inclusion Criteria: * Documented diagnosis of AML with either refractory or relapsed disease or diagnosis of MDS and ≥ 5% BM blasts * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Adequate hematologic status: * Absolute lymphocyte count (ALC) \> 100/mm3 * Adequate renal, hepatic, cardiac and pulmonary function: * ALT and AST \< 3.0 × the ULN * Creatinine clearance ≥ 45.0 mL/min as estimated by Cockcroft-Gault and independent dialysis * Total bilirubin ≤ 2.0 mg/dL * Pregnancy testing: females of childbearing potential must have a negative serum or urine pregnancy test * Contraception: males and females of childbearing potential must agree to use an effective method of contraception * Participant is capable of giving signed informed consent Exclusion Criteria: * Participants with acute promyelocytic leukemia * Presence of active and clinically relevant central nervous system (CNS) disorder * Autoimmune disease requiring immunosuppressive treatment * Participants with known hepatic bridging cirrhosis * Currently active infection with hepatitis B or C * Previous treatment with investigational gene or cell therapy (including CAR therapy) * Any active acute GvHD or systemic treatment of more than 10 mg prednisone daily (or equivalent) * Previous chemotherapy including biologic/targeted therapy or immunological agents directed to the pathology within 14 days prior to screening and all along the study duration