Keytruda (pembrolizumab) is an immunotherapy cancer treatment that stimulates the patient’s immune system to help fight certain types of cancers. Because cancer cells can use certain proteins, like the PD-1 protein, to shield themselves from detection, this enables cancer cells to grow and spread. Keytruda blocks these proteins, preventing the cancer from hiding. The treatment is then able to help the immune system do its job: Find the cancer cells and destroy them. In this video, oncologist Dr. Stephen Lemon explains how Keytruda works, including what types of side effects patients may experience. Keytruda is currently approved for the treatment of malignant Melanoma, as well for other types of cancers, including Non-small Cell Lung Cancer, Head and Neck Squamous Cell Cancer, Hodgkins Lymphoma, Bladder Cancer and other cancers that are positive for MSI. Keytruda is developed by Merck. It’s generic name is pembrolizumab. Stephen Lemon MD is a medical oncologist at the Overlake Hospital Cancer Treatment Center in Bellevue, WA.