PD-1, short for Programmed Death 1 (PD-1) receptor, a member of the B7 protein superfamily, is overexpressed on certain tumor cell types and on various tumor-infiltrating immune cells, and has two ligands, PD-L1 and PD-L2. An advantage of targeting PD-1 is that it can restore immune function in the tumor microenvironment.



PD-1, a programmed death receptor 1, is a member of the b7 protein superfamily, which expressed in some types of tumor cells and in immune cells that infiltrate various types of tumors. PD-L1 is a ligand of PD-1. The immunomodulation targeting PD-1 is of great significance in anti-tumor, anti-infection, anti-autoimmune disease and organ transplantation.

PD-1 is an important immunosuppressive molecule, mainly expressed in activated T cells and B cells. At the same time, PD-L1, a ligand with high expression of PD-1, was found in tumor cells. When the immune system of the body is monitored, the PD-1 pathway in tumor microenvironment is continuously activated, which results in the decrease of immune function. PD-1/ PD-L1 inhibitor can block the binding of PD-1 and PD-L1, block the negative regulatory signal, restore the activity of T cells, and enhance the immune response. PD-1 / PD-L1 inhibitor is effective in tumor immunotherapy.

PD-1 inhibitors

Pembrolizumab (Keytruda)

Pembrolizumab is an effective and highly selective monoclonal antibody against IgG4-kappa, which can target against PD-1 and is an inhibitor of PD-1. Pembrolizumab is used to treat advanced or unresectable melanoma that is unresponsive to other drugs. The side effects of pembrolizumab are often accepted by patients, and the curative effect is improved in patients with high expression of PD-L1 in tumor cells. Now embroplizumab, a new cancer drug for cancer immunotherapy, has been approved by the Food and Drug Administration (FDA).


Nivolumab is a monoclonal antibody that binds to the programmed death receptor (PD-1). By blocking the interaction between PD-1 and its ligand PD-L1 and PD-L2, it blocks the immunosuppressive response mediated by PD-1 pathway. Including anti-tumor immunoreaction. Nivolumab is mainly used in the treatment of melanoma and non-small cell lung cancer.

Immunotherapy of tumor

Normally, the immune system can identify and remove tumor cells from the tumor microenvironment, but in order to survive and grow, tumor cells can adopt different strategies to suppress the immune system of the human body and not kill tumor cells normally. Tumor immunotherapy is a method to control and remove tumor by restarting and maintaining tumor-immune circulation and restoring normal anti-tumor immune response.

Nonsmall-cell lung cancer (NSCLC)

In the clinical study, both NSCLC treated patients and pembrolizumab showed higher activity. Nivolumab could make the total remission rate of NSCLC patients up to 17, and the duration of remission could reach more than 18 months. The total remission rate of NSCLC patients was 21.


Nivolumab and pembrolizumab have significant immunological effects on melanoma. When nivolumab and ipilimumab were used together, the patients benefited greatly. Similarly, the remission rate of the patients was greatly increased to 57.6, nivolumab was 43.7, and the remission rate of ipilimumab was 19.7%.