Strategies for delivery of dual-targeting CAR T cells. CD19 and CD22 are shown as an example of antigenic targets. (A) Coadministration: 2 independent products are generated and infused into patients. (B) Cotransduction: T cells are transduced with 2 different vectors, generating 1 single product with a mixed population of single antigen–targeted and bispecific CAR T cells. (C) Bicistronic vector: 1 single vector with binding domains for 2 different antigens is used. The vector is then cleaved and generates CAR T cells with 1 CAR for each antigen on their surface. (D) Bivalent tandem CAR: 1 vector generates 1 single CAR on the surface of the cell. That CAR has binding domains for 2 different antigens. TM, transmembrane; VH, variable heavy chain; VL, variable light chain.