CD19 and precursor B-cell acute lymphoblastic leukemia: In August 2017, a major milestone in the treatment of r/r B-cell acute lymphoblastic leukemia (B-ALL) was achieved with FDA approval of the first gene therapy (Novartis) (6), a CD19-targeted CAR-T cell–based product, tisagenlecleucel (CTL019) for B-ALL in children and young adults up to 25 years of age.