PD-1 /PD L-1 checkpoint inhibitor is the new hope for Cancer Treatment

 What are Checkpoint inhibitors?

Checkpoint inhibitors are a group of proteins that can treat cancer potentially. Checkpoint inhibitor therapy is a form of cancer immunotherapy that targets immune checkpoint.

Immune checkpoints are the immune regulators, as the name denotes itself, that regulate or control the activity of immune cells, enhancing the self-tolerance of the immune system. These inhibitors when stimulated hampers the immune response to an immunologic stimulus.

Checkpoint Therapy to combat Cancer

Some cancerous cells do protect themselves from getting attacked by activating the immune checkpoint targets. Once activated, they block the inhibitory checkpoints, and restore the functioning of the immune checkpoints.

CTLA-4 inhibitors, PD-1 inhibitors and PD-L1 inhibitors are the checkpoint inhibitors that are used to treat cancers.

PD-1 inhibitors and PD-L1 inhibitors are a group of checkpoint inhibitors that are present on the surface of the cell. These immune checkpoint inhibitors are recognized as the emerging front-line treatment for the cancer.

The first anti-cancer drug developed to target immune checkpoint was ipilimumab, a CTLA4 blocker, which was approved in the US in the year 2011.

PD-1, a checkpoint protein present on immune T cells, normally prevent the attack by T-cells on other cells in the body. When PD-1 attaches to PD-L1, it releases a protein telling T-cells to not attack the other cells.

This property is highly utilized by some cancerous cells as they have large amounts of PD-L1, thus evading the attack.

So, basically PD-1 and PD-L1 switches off the T-cells.

Some of the therapies developed using PD-1 checkpoint inhibitors are Opdivo and Keytruda.

Opdivo

Opdivo (Nivolumab), a targeted therapy, is a human programmed death receptor-1 (PD-1) blocking antibody.

Opdivo  has been approved for the treatment of unresectable or metastatic melanoma, advanced renal cell cancer in, Hodgkin’s lymphoma (cHL), locally advanced or metastatic urothelial carcinoma, metastatic small cell lung cancer (SCLC), unresectable or metastatic, microsatellite instability-high (MSI-H), hepatocellular cancer (HCC) under specific conditions.

Keytruda

Keytruda therapy is administered when the tumour tests positive for PD-1.

Keytruda has been recommended for skin cancer called melanoma; a kind of lung cancer called non–small cell lung cancer (NSCLC), head and neck squamous cell cancer (HNSCC), classical Hodgkin lymphoma (cHL) primary mediastinal B-cell lymphoma (PMBCL), Advanced urothelial cancer, advanced gastric cancer and others.

Atezolizumab

Atezolizumab is a drug which binds to a protein called PD-L1 and is traded under the name Tecentriq. It has been approved for the treatment of locally advanced or metastatic urothelial carcinoma.