A phase 2, global, multicenter study evaluated the safety and efficacy of tisagenlecleucel, an anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, in children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). The study included 75 patients who received a single infusion of tisagenlecleucel. The overall remission rate within 3 months was 81%, with all patients achieving negative minimal residual disease. Event-free survival at 6 months was 73%, and overall survival at 6 months was 90%. At 12 months, event-free survival was 50% and overall survival was 76%. The median duration of remission was not reached, but tisagenlecleucel persisted in the blood for up to 20 months. Grade 3 or 4 adverse events occurred in 73% of patients, with cytokine release syndrome affecting 77% of patients. Neurologic events occurred in 40% of patients, managed with supportive care. The therapy showed durable remission with long-term persistence of CAR T cells, and the safety profile was comparable to a previous single-center study. The study demonstrated that tisagenlecleucel is effective in treating relapsed or refractory B-cell ALL, with high remission rates and long-term survival. The therapy was associated with transient high-grade toxic effects, including cytokine release syndrome and neurologic events, which were managed with supportive care and cytokine blockade. The study highlights the potential of CAR T-cell therapy in treating pediatric and young adult patients with B-cell ALL, with a favorable safety profile and durable remission. The results support the use of tisagenlecleucel as a promising treatment option for relapsed or refractory B-cell ALL.A phase 2, global, multicenter study evaluated the safety and efficacy of tisagenlecleucel, an anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, in children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). The study included 75 patients who received a single infusion of tisagenlecleucel. The overall remission rate within 3 months was 81%, with all patients achieving negative minimal residual disease. Event-free survival at 6 months was 73%, and overall survival at 6 months was 90%. At 12 months, event-free survival was 50% and overall survival was 76%. The median duration of remission was not reached, but tisagenlecleucel persisted in the blood for up to 20 months. Grade 3 or 4 adverse events occurred in 73% of patients, with cytokine release syndrome affecting 77% of patients. Neurologic events occurred in 40% of patients, managed with supportive care. The therapy showed durable remission with long-term persistence of CAR T cells, and the safety profile was comparable to a previous single-center study. The study demonstrated that tisagenlecleucel is effective in treating relapsed or refractory B-cell ALL, with high remission rates and long-term survival. The therapy was associated with transient high-grade toxic effects, including cytokine release syndrome and neurologic events, which were managed with supportive care and cytokine blockade. The study highlights the potential of CAR T-cell therapy in treating pediatric and young adult patients with B-cell ALL, with a favorable safety profile and durable remission. The results support the use of tisagenlecleucel as a promising treatment option for relapsed or refractory B-cell ALL.