Other names: anti-programmed cell death-1 (PD-1) monoclonal antibodies, immune checkpoint inhibitors, programmed death-ligand 1 (PD-L1) blocking antibodies
Programmed cell death protein 1 (PD-1) is an inhibitory receptor that is expressed on some tumor cells and causes down regulation of the immune system by reducing T-cell activity. Anti-PD-1 monoclonal antibodies block the PD-1 receptor so the T cells are no longer inhibited and therefore activates the immune response against the tumor.