CD19 and acute lymphoblastic leukemia: In pivotal phase 2 trials of relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL), tisagenlecleucel achieved an overall remission rate (complete remission or complete remission with incomplete hematologic recovery) of 81% within 3 months in pediatric and young adult patients (3), and CD19-directed CAR T cells induced complete remission in 83% of adults with B-ALL (4).