Allogeneic Engineered Hematopoietic Stem Cell Transplant (HCT) Lacking the CD33 Protein, and Post-HCT Treatment With Mylotarg, for Patients With CD33+ AML or MDS

Inclusion Criteria: 1. Must be ≥18 and ≤70 years of age. 2. Patients with AML must have one of the following groups of features that are known to be a risk factor for leukemia relapse: * BM in morphological remission (\<5% blasts) with adverse-risk disease related genetics at presentation (according to European Leukemia-Net guidelines \[ELN, Döhner 2017\]), or * Intermediate risk genetics in morphologic remission (\<5% blasts) with other recognized high risk criteria such as MRD+ following therapy, or * BM with evidence of persistent leukemia 5-10% blasts post induction/salvage therapy. Patients with BM Blast count \>10% may participate with Sponsor Medical Monitor approval. (Note: these patients may have disease-related genetics of any risk criteria at presentation), or * Any patient in second or greater remission. 3. Patients with MDS must have all of the following: * Previous or current IPSS-R score of High or Very High risk; AND * Previous or current MDS-IB1 or MDS-IB2 per the 2022 WHO criteria (Khoury 2022) 4. AML sample from the patient must have evidence of CD33 expression (\>0%) 5. Candidate for HLA-matched allogeneic HCT using a myeloablative conditioning regimen. 6. Must have a related or unrelated stem cell donor that is a 8/8 match for HLA-A, -B, -C, and -DRB1. 7. Must have adequate performance status and organ function as defined below: 1. Performance Status: Karnofsky score of ≥70. 2. Cardiac: left ventricular ejection fraction (LVEF) ≥50% 3. Pulmonary: diffusing capacity of lung for carbon monoxide (DLCO), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) ≥66%. 4. Renal: estimated glomerular filtration rate (GFR) \>60 mL/min 5. Hepatic: total bilirubin \<1.5 × ULN, or if ≥1.5 × ULN direct bilirubin \<ULN and ALT/AST \<1.5 × ULN (per institutional criteria). Exclusion Criteria: 1. Prior autologous or allogeneic stem cell transplantation. 2. Presence of the following disease-related genetics: t(15; 17)(q22; q21), or t(9; 22)(q34; q11), or other evidence of acute promyelocytic leukemia or chronic myeloid leukemia. 3. Prior treatment with Mylotarg™ (gemtuzumab ozogamicin) in the past 3.5 months. 4. Active central nervous system (CNS) leukemia. 5. Patients diagnosed with Gilbert's syndrome. 6. Uncontrolled bacterial, viral, or fungal infections; or known human immunodeficiency virus (HIV), Hepatitis B, or Hepatitis C infection.