Precision-T: A Randomized Study of Orca-T in Recipients Undergoing Allogeneic Transplantation for Hematologic Malignancies

Key Inclusion Criteria: * Matched to a related or unrelated donor who is an 8/8 match for HLA-A, -B, -C, and DRB1 * Diagnosed with one of the following diseases: * Acute myeloid, lymphoid or mixed phenotype leukemia in complete remission (CR) or CR with incomplete hematologic recovery (CRi), with or without the presence of known minimal residual disease * Myelodysplastic syndromes (MDS) that are indicated for alloHSCT per 2017 International Expert Panel recommendations and/or have therapy-related/secondary MDS, with ≤ 10% blast burden in the bone marrow * Planned to undergo MA-alloHCT including one of the following myeloablative conditioning regimens: * TBI/Cy * TBI/Etoposide * BFT * Cardiac ejection fraction at rest ≥ 45% or shortening fraction of ≥ 27% by echocardiogram or radionuclide scan (MUGA) * Diffusing capacity of the lung for carbon monoxide (DLCO) (adjusted for hemoglobin) ≥ 50% * Negative serum or urine beta-HCG test in females of childbearing potential * ALT/AST \< 3 times ULN * Recipients in screening must screen negative for SARS-CoV-2 RNA using a PCR-based test * Disease Risk Index (DRI) overall risk categorization of intermediate or high * Total bilirubin ≤ upper limit of normal (ULN) * Estimated glomerular filtration rate (eGFR) ≥ 60 mL/minute Key Exclusion Criteria: * Prior allogeneic HCT * Currently receiving corticosteroids or other immunosuppressive therapy. Topical corticosteroids or oral systemic corticosteroid doses less than or equal t…