Which PD-1 inhibitor is used in immunotherapy?

The correct answer is Keytruda (pembrolizumab), which is a PD-1 inhibitor used in immunotherapy. Pembrolizumab targets the programmed death-1 (PD-1) receptor on T cells, blocking its interaction with PD-L1 and PD-L2, which are ligands that promote immune suppression. This mechanism enhances the immune response against cancer cells, allowing the body’s immune system to recognize and attack tumors more effectively.

Nivolumab is also a PD-1 inhibitor and works on the same principle as pembrolizumab, so it’s important to recognize that both this option and pembrolizumab are significant in the field of cancer immunotherapy. However, Keytruda is more widely recognized and often referred to in practice and literature regarding PD-1 inhibitors.

Durvalumab and atezolizumab, while important in cancer treatment, are not classified as PD-1 inhibitors; they target the PD-L1 molecule instead, which is a different pathway in the immune checkpoint blockade strategy. This distinction clarifies the specific role of pembrolizumab as a PD-1 inhibitor in therapeutic applications.