Key Points

Pembrolizumab (brand name: Keytruda) is a type of immunotherapy drug known as an Immune Checkpoint Inhibitor. It blocks the PD-1 (programmed death receptor-1) pathway to help prevent cancer cells from hiding from the immune system. Pembrolizumab is not a chemotherapy drug or radiation treatment and does not attack cancer cells directly.

Pembrolizumab treats many different types of cancers, including lung cancer, melanoma (a type of skin cancer), and triple negative breast cancer.

Here’s how it works:

• Checkpoint inhibitors like pembrolizumab help to boost your own immune system response against cancer.
• T-cells (also called T-lymphocytes) are a type of white blood cell. Normally, when cancer cells circulate in your body, your immune system activates T-cells to target and destroy these cells. T-cells help your body to detect and fight infections, disease and play an important role in fighting cancer, too.
• But some cancer cells can avoid detection by attaching to receptor sites found on the T-cells known as PD-1. This prevents the activation of the T-cell which normally would target and destroy the cancer. The cancer cells can then multiply and spread.
• When a PD-1 immune checkpoint inhibitor such as pembrolizumab (Keytruda) is given, it binds to the PD-1 receptor on the T-cell. This helps to block the cancer cells from linking to and inactivating the T-cells. Pembrolizumab can allow re-activation of the immune system T-cells to help fight off the cancer.
• While having an effect on the tumor, this could also affect normal healthy cells. It is important to understand the possible side effects with this drug. Discuss this information with your doctor.

Related: Pembrolizumab side effects (in more detail)

Bottom Line

Pembrolizumab (Keytruda) is a type of immunotherapy drug known as an Immune Checkpoint Inhibitor. It blocks the PD-1 (programmed death receptor-1) pathway to help prevent cancer cells from hiding from the immune system.

Pembrolizumab binds to the PD-1 receptor on the T-cell and helps to block the cancer cells from linking to and inactivating the cancer-fighting T-cells. While having an effect on the tumor, this could also affect normal healthy cells.

Pembrolizumab is not a chemotherapy drug or radiation treatment and does not attack cancer cells directly.

This is not all the information you need to know about pembrolizumab for safe and effective use and does not replace your doctor's advice. Review the full pembrolizumab (Keytruda) product information here, and discuss this information with your doctor or other health care provider before you start treatment.