A Study of CD19 Targeted CAR T Cell Therapy in Adult Patients With Relapsed or Refractory B Cell Acute Lymphoblastic Leukaemia (ALL)

Inclusion Criteria: * Age 18 years or older Age 18 years or older * ECOG performance status of 0 or 1 * Relapsed or refractory B cell ALL * Patients with Ph+ ALL are eligible if intolerant to TKI, failed two lines of any TKI, or failed one line of second-generation TKI, or if TKI is contraindicated * Documented CD19 positivity within 1 month of screening * Phase Ib: Primary Cohort IA: Presence of ≥5% blasts in BM at screening * Phase Ib: Exploratory Cohort IB: MRD-positive defined as ≥ 1e-4 and \<5% blasts in the BM at screening * Phase II: Primary Cohort IIA: Presence of ≥5% blasts in BM at screening * Phase II: Cohort IIB: ≥2nd CR or CRi with MRD-positive defined as ≥1e-3 by central ClonoSEQ® NGS testing and \<5% blasts in the BM at screening * Adequate renal, hepatic, pulmonary, and cardiac function Exclusion Criteria: * Phase Ib (Cohort IA and Cohort IB) and Phase II (Cohort IIA and Cohort IIB) B-ALL with isolated EM disease * Diagnosis of Burkitt's leukaemia/lymphoma or CML lymphoid in blast crisis * History or presence of clinically relevant CNS pathology * Presence of CNS-3 disease or CNS-2 disease with neurological changes * Presence of active or uncontrolled fungal, bacterial, viral, or other infection requiring systemic antimicrobials for management * Active or latent Hepatitis B virus or active Hepatitis C virus * Human Immunodeficiency Virus (HIV), HTLV-1, HTLV-2, syphilis positive test * Prior CD19 targeted therapy other than blinatumomab. Patients who have experienced Grade 3 or higher neurotoxicity following blinatumomab.