Myers RM, Li Y, Leahy AB, et al. - A humanized CD19 chimeric antigen receptor (CAR) T-cell product (huCART19) was developed by researchers with an objective of offering an effective treatment for relapse due to poor CAR T-cell persistence. In this pilot clinical trial, they tested huCART19 among children and young adults suffering from relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL) (n = 72) or B-lymphoblastic lymphoma (n = 2), treated in two cohorts: with (retreatment, n = 33) or without (CAR-naive, n = 41) prior CAR exposure. The likelihood of losing huCART19 persistence, at 6 months, was estimated to be 27% and 48% for CAR-naive and for retreatment patients, respectively, whereas the incidence of B-cell recovery was 15% and 58%, respectively. In the CAR-naive cohort, the relapse-free survival at 12 and 24 months was estimated to be 84% and 74%, and it was 74% and 58%, respectively, in the retreatment cohort. Findings showed that durable remissions with long-term persistence were conferred by huCART19 in children and young adults experiencing relapsed or refractory B-ALL, including post-failure of prior CAR T-cell therapy.