Release brakes: chimeric antigen receptor T cells with PD-1 switch receptor

Adoptive cell therapy chimeric antigen receptor (CAR) redirected T cells is efficacious in the therapy of hematologic malignancies, however, challenging in the treatment of solid cancer due to massive immune repression within the tumor lesion. Recent reports by Kobold et al. (1) and Liu et al. (2) explored the concept to provide CD28 costimulation by a co-expressed “switch receptor” targeting PD-1 ligands to overcome repression and to make the redirected T cell response more durable in the tumor tissue.