The immune system normally helps protect the body against germs, and it can also help destroy cancer cells. Immunotherapy is the use of medicines to stimulate a person’s own immune system to recognize and destroy cancer cells more effectively. It can be used to treat some people with advanced basal or squamous cell skin cancer.
An important part of the immune system is its ability to keep itself from attacking normal cells. To do this, it uses “checkpoints”, which are proteins on immune cells that need to be turned on (or off) to start an immune response.
Cancer cells sometimes use these checkpoints to avoid being attacked by the immune system. But drugs that target checkpoint proteins, called checkpoint inhibitors, can help restore the immune response against cancer cells.
Cemiplimab (Libtayo) and pembrolizumab (Keytruda) are drugs that target PD-1, a checkpoint protein on T cells (a type of immune system cell) that normally helps keep these cells from attacking other cells in the body. By blocking PD-1, these drugs can boost the immune response against cancer cells.
These drugs are given as an intravenous (IV) infusion. Cemiplimab is typically given once every 3 weeks, while pembrolizumab can be given every 3 weeks or every 6 weeks.
These drugs haven't been studied in people with weakened immune systems, such as people who take medicines for autoimmune diseases or who have had an organ transplant, so the balance between benefits and risks in these people isn’t clear.
Cemiplimab or pembrolizumab can be used to treat people with advanced squamous cell skin cancer that cannot be cured with surgery or radiation therapy.
Cemiplimab can be used to treat advanced basal cell skin cancer in people who are no longer being helped by (or cannot take) the targeted drugs called hedgehog pathway inhibitors.
Common side effects of these drugs can include:
Other, more serious side effects occur less often:
Infusion reactions: Some people might have an infusion reaction while getting one of these drugs. This is like an allergic reaction, and can include fever, chills, flushing of the face, rash, itchy skin, wheezing, and trouble breathing.
Autoimmune reactions: These drugs work by basically removing one of the safeguards that keeps the immune system from attacking other parts of the body. This can sometimes lead to serious or even life-threatening problems in the lungs, intestines, liver, hormone-making glands, kidneys, or other organs.
It’s very important to report any new side effects to your health care team right away. If serious side effects do occur, treatment may need to be stopped and you may get high doses of corticosteroids to suppress your immune system.
To learn more about this type of treatment, see Immune Checkpoint Inhibitors to Treat Cancer.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Christensen SR, Wilson LD, Leffell DJ. Chapter 90: Cancer of the Skin. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.
Martins RG. Systemic treatment of advanced cutaneous squamous and basal cell carcinomas. UpToDate. 2019. Accessed at https://www.uptodate.com/contents/systemic-treatment-of-advanced-cutaneous-squamous-and-basal-cell-carcinomas on June 4, 2019.
National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Squamous Cell Skin Cancer. Version 2.2019. Accessed at www.nccn.org/professionals/physician_gls/pdf/squamous.pdf on June 4, 2019.
Xu YG, Aylward JL, Swanson AM, et al. Chapter 67: Nonmelanoma Skin Cancers. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2020.
Last Revised: February 10, 2021
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.