A Study of CD19 Targeted CAR T Cell Therapy in Pediatric Patients With Relapsed or Refractory B Cell Acute Lymphoblastic Leukemia (B ALL) and Aggressive Mature B-cell Non-Hodgkin Lymphoma (B NHL)

This trial is testing a personalized cell therapy called CAR T cell therapy — where a patient's own immune cells are reprogrammed to attack cancer — for children with relapsed or treatment-resistant B cell leukemia (B-ALL) or aggressive B cell lymphoma (B-NHL). **You may be eligible if...** - You are under 18 years old and weigh at least 6 kg - You have been diagnosed with relapsed or refractory B cell acute lymphoblastic leukemia (B-ALL) or aggressive B cell lymphoma (such as diffuse large B cell lymphoma or Burkitt's lymphoma) - Your cancer cells test positive for the CD19 protein - You have adequate kidney, liver, lung, and heart function **You may NOT be eligible if...** - You have chronic myelogenous leukemia in blast crisis - You have active, uncontrolled infections - You have significant central nervous system disease unrelated to leukemia - You have previously received certain CAR T cell therapies targeting CD19 Talk to your doctor to see if this trial is right for you.