Trial Evaluating MGTA-456 in Patients With High-Risk Malignancy

Age, Unit Cell Dose and HLA Match Criteria * Subjects must be ≤55 years of age * Subjects must weigh \>11 kg * Subjects must have a partially HLA matched UCB unit with a pre-cryopreserved TNC dose \>1.0 x 107 per kilogram recipient weight. HLA matching is initially based on a minimum of 5 of 8 HLA alleles at high resolution A, B, C, DRB1 typing; searches will be performed according to the current Magenta Cord Blood Search Algorithm. Eligible Diseases: * Acute myelogenous leukemia (AML) in morphological complete remission with: * Minimal residual disease (MRD) by flow cytometry, or * Intermediate to high risk leukemia in first (CR1) based on institutional criteria, eg. not favorable risk AML which is defined as having one of the following: * t(8,21) without cKIT mutation * inv(16) or t(16;16) without cKIT mutation * Normal karyotype with mutated NPM1 but FLT3-ITD wild type * Normal karyotype with double mutated CEBPA * Acute promyelocytic leukemia (APL) in first molecular remission at the end of consolidation * Any second or subsequent CR, or * Secondary AML with prior malignancy that has been in remission for at least 12 months. * Acute lymphocytic leukemia (ALL) at the following stages: * High risk first morphological, cytogenetic and molecular CR with: * MRD by flow cytometry, or * Diagnosis of Philadelphia chromosome (Ph)+ ALL, or * MLL rearrangement at diagnosis with slow early response at Day 14, or * Hyp…