Kaplan-Meier curves of (A) Leukemia-Free Survival (LFS) (B) Event-Free Survival (EFS) (C) Overall Survival (OS), and (D) time to loss of B-cell aplasia (BCA), comparing subjects treated with SCRI-CAR19v2 (purple) versus SCRI-CAR19v1 (green). Subjects treated with SCRI-CAR19v2 had significantly better LFS (P=0.0091), EFS (P=0.043), and time to loss of BCA (P=0.019). No significant difference was observed in OS (P=0.26) between groups. P values were calculated via log-rank test with weights=1. (E) Mean absolute CAR T–cell engraftment (cells/μL) values at infusion and 10, 14, 21, and 63 days after T-cell infusion are plotted on the primary y-axis along with standard error of the mean. Mean CAR T–cell composition breakdown, namely %CD4+ and %CD8+ of total EGFRt+ cells, at 10, 14, 21, and 63 days after T-cell infusion are scaled to 100% and plotted on the secondary y-axis. (F) CAR T–cell composition breakdown at long term follow up (LTFU) visits ranging from 3 months (3M) to 54 months (54M) after T-cell infusion are plotted in scattered dots. The colors of the dots denote the corresponding LTFU visit timepoint and the sizes of the dots represent the total CAR T–cell engraftment in %EGFRt+ of CD3+ detected at each visit timepoint. Regions corresponding to more %CD8+ and %CD4+ in the CAR T-cell composition breakdown are highlighted for clarity.