Dual Anti-CD22/CD19 Chimeric Antigen Receptor-directed T Cells (CART2219.1) for Relapsed Refractory B-Lineage Leukaemia

Inclusion Criteria: All Cohorts: * Age 2 to 75 years * Absolute blood CD3+ T cell count ≥100/μl * ECOG performance score of ≤2 if \>16 years old, or Lansky performance score of \>50 if ≤16 years old at screening * Patients and/or parents must give their written informed consent/assent. * Patients have relapsed/refractory B-lineage acute lymphoblastic leukaemia, includes persistent minimal residual disease (MRD) Cohort 1 (Phase I): Relapsed/Refractory B-ALL * Patients must have relapsed/refractory (r/r) B-lineage ALL meeting one of the following disease-specific criteria: * Patients with r/r ALL with \>5% blasts in BM (M2 or M3) after at least one standard chemotherapy and one salvage regimen who are ineligible for allogeneic stem cell transplant (alloSCT) or have refractory disease activity (e.g. persistent MRD in bone marrow) precluding alloSCT, or * Patients with Ph+ ALL if they are intolerant to tyrosine kinase inhibitor (TKI) therapy, or if they have r/r disease after treatment including TKI, or * Patients who have relapsed post-allogeneic HSCT and are at least 100 days post-transplant, with no evidence of active GVHD, \> 6 weeks post donor lymphocyte infusion (DLI) and no longer taking immunosuppressive agents for at least 30 days prior to enrolment. * Patients who have relapsed after prior CAR-T therapy who are not eligible for stem cell transplant and have \< 5% circulating CAR-T prior to apheresis * Patients with refractory/relapsed combined extramedullar…