Loqtorzi (toripalimab) is a programmed death receptor-1 (PD-1) blocking antibody that binds to the PD-1 protein on T-cells (a type of immune cell). It works by blocking PD-L1 and PD-L2 molecules found on the surface of some cancer cells. This allows the immune system to activate and kill the tumor. Loqtorzi is the first FDA-approved agent for nasopharyngeal carcinoma (NPC).