nivolumab + tislelizumab

This is a combination of two separate PD-1 inhibitor monoclonal antibodies. Nivolumab is a fully human IgG4 antibody targeting the immune checkpoint programmed death receptor-1 (PD-1). Tislelizumab is a humanized IgG4 variant monoclonal antibody against PD-1 that was engineered to have a nullified Fc portion, minimizing binding to FcγR on macrophages and limiting treatment resistance via antibody-dependent phagocytosis. Both drugs work by blocking PD-L1/PD-L2–mediated cell signaling, restoring T-cell function and resulting in immune-mediated antitumor responses. While both are PD-1 inhibitors, they have different binding characteristics - tislelizumab has a much slower dissociation rate from PD-1 compared to nivolumab, resulting in higher target affinity.