Study of CD19 Allogeneic Memory T-cell Therapy for Relapsed/Refractory CD19+ Leukemia

Inclusion Criteria Eligibility Criteria for Donors: Apheresis and Manufacturing * Age ≥ 18 years old * At least single haplotype matched (≥ 3/6) family member * HIV negative * For females of child bearing age: Not pregnant as confirmed by negative serum or urine pregnancy test within 14 days prior to enrollment AND Not lactating with intent to breastfeed * Completed the process of donor eligibility determination as outlined in 21 CFR 1271 and agency guidance. \*For Cohort A only, an ineligible donor may be used under urgent medical need if the reason for ineligibility was previously present at time of transplant determination. For Cohort A only, identified recipient with relapsed and/or refractory CD19-positive leukemia For Cohort B only, iIdentified recipient with relapsed and/or refractory CD19-positive leukemia who is not suitable to receive autologous CD19-CAR T-cell therapy as defined by the following: * Relapsed and/or refractory disease despite prior treatment with autologous CD19- CAR T-cell therapy * History of prior autologous leukapheresis failure * History of prior autologous CAR T-cell manufacturing failure * Unable to undergo autologous leukapheresis in the opinion of the study PI(s): examples may include - patient small size/low weight, inadequate T-cell counts, rapidly progressive leukemia, clinical status not amenable to apheresis Eligibility Criteria for Patients: Pre-Treatment Evaluation\* Inclusion • MEMCAR19 recipient candidate ≤\<21 years old with rRelapsed and/or refractory CD19-positive leukemia. \*Due to potential scheduling challenges, all recipients may not be offered the Pre-Treatment Evaluation consent. This will not be counted as a deviation. Eligibility Criteria for Patients:Treatment * Age ≤ 21 years old * Relapsed and/or refractory CD19-positive leukemia\*: * Refractory disease (defined as any of the following): * Primary refractory disease despite at least 2 cycles of an intensive chemotherapy regimen designed to induce remission * Refractory disease despite salvage therapy * Relapsed disease (defined as any of the following): * 2nd or greater relapse * Any relapse after allogeneic hematopoietic cell transplantation (HCT) * 1st relapse if patient requires an allogeneic HCT as part of standard of care relapse therapy, but is found to be ineligible and/or unsuitable for HCT CD19-positivity confirmed within 2 months and after receipt of any CD19-directed therapy * Patient cohorts: * Cohort A: patient has previously received a HCT from the selected CAR T-cell donor * Cohort B - patient has NOT previously received a HCT from the selected CAR T-cell donor. * For Cohort B only, not suitable to receive autologous CD19-CAR T-cell therapy as defined above in Criteria: Eligibility Criteria for Donors: Apheresis and Manufacturing * Detectable medullary CD19-positive leukemia * Estimated life expectancy of ≥ 8 weeks * Karnofsky or Lansky performance score ≥ 50 * No CNS-3 disease or any level of detectable leukemia in CNS with associated neurologic symptoms * If history of allogeneic HCT (regardless of donor type), prior to planned CAR T-cell infusion, must meet the following criteria: * ≥ 3 months from HCT * have recovered from prior HCT therapy * have no evidence of active GVHD within prior 2 months * have not received a donor lymphocyte infusion (DLI) within the 28 days prior to planned CAR T-cell infusion * Adequate cardiac function: left ventricular ejection fraction ≥ 40% or shortening fraction ≥ 25% (function may be supported by pharmacologic therapy) * EKG without evidence of clinically significant arrhythmia * Adequate renal function: creatinine clearance or radioisotope GFR 50 ml/min/1.73m2 (GFR 40 ml/min/1.73m2 if \< 2 years of age) * Adequate pulmonary function: forced vital capacity (FVC) ≥ 50% of predicted value; or pulse oximetry ≥ 92% on room air if patient is unable to perform pulmonary function testing * Total bilirubin ≤ 3 times the upper limit of normal for age, except in subjects with Gilbert's syndrome * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≤ 5 times the upper limit of normal for age * No history of HIV infection * No evidence of severe, uncontrolled bacterial, viral or fungal infection * Has recovered from all NCI CTAE grade III-IV, non-hematologic acute toxicities from prior therapy * For females of child bearing age: * Not pregnant with negative serum or urine pregnancy test ≤ 7 days prior to enrollment AND Not lactating with intent to breastfeed * If sexually active, agreement to use birth control until 6 months after CAR T-cell infusion * No history of hypersensitivity reactions to murine protein-containing products * Not receiving systemic steroids therapy exceeding the equivalent of 0.5 mg/kg/day of methylprednisolone ≤ 7 days prior to CAR T-cell infusion * Not receiving systemic therapy ≤ 14 days prior to CAR T-cell infusion, which will interfere with the activity of the CAR T-cell product in vivo (in the opinion of the study PI(s)) * Not receiving intrathecal chemotherapy ≤ 7 days prior to CAR T-cell infusion Exclusion Criteria: NA