RecruitingPhase 1Drug trialUCD19 CAR T Therapy in Adults With B-ALL and MRD Positivity in CR1This open-label, single arm Phase 1/1b trial aims to determine the safety and tolerability of anti-CD19 chimeric antigen receptor-expressing (CAR) T cells (UCD19 CAR T) in adults with B-ALL that are in first complete remission with MRD positivity. This trial will enroll 10 patients during Phase 1 for apheresis, treatment with lymphodepleting chemotherapy, and UCD19 CAR T cell infusion. Patients will be assessed for DLTs (within 42 days after CAR T infusion) to determine a maximum tolerated dose (MTD), duration of B cell aplasia, overall response rate (at 1-3-, 6- and 12-months), and overall survival and event free survival (at 12- and 24- months) post UCD19 CAR T infusion. After the initial dose escalation phase, an additional 12 participants will be enrolled in the dose expansion at the MTD to determine preliminary efficacy.