CD19 and acute lymphoblastic leukemia: These unprecedented outcomes, including complete responses in >80–90% of adults and children with relapsed/refractory acute lymphoblastic leukemia (ALL),3 led to rapid Food and Drug Administration (FDA) regulatory approval of the CD19-directed CAR-T cell products Kymriah and Yescarta in the United States in 2017, and in Europe and other parts of the world the following year, to treat ALL and diffuse large B cell lymphoma.