- Adoptive cellular therapy with T cells genetically modified using viral-basedvectors to express chimeric antigen receptors targeting the CD19 molecule have demonstrated dramatic clinical responses in patients with acute lymphoblastic leukemia (ALL). However, not all patients respond and CD19-negative escape has been observed following CD19 CAR therapy, as well as anti-CD19/CD3 bispecific antibody therapy. Thus, additional targets are needed.