immune checkpoint inhibitor medicine Ask the Chatbot a Question More Actions Share Share Share to social media Facebook X URL https://www.britannica.com/science/immune-checkpoint-inhibitor Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.

　　External Websites Ask the Chatbot a Question Also known as: ICI Written by Kara Rogers Kara Rogers is the senior editor of biomedical sciences at Encyclopædia Britannica, where she oversees a range of content from medicine and genetics to microorganisms. She joined Britannica in 2006 and... Kara Rogers Fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... The Editors of Encyclopaedia Britannica Last Updated: Aug 25, 2025 • Article History Table of Contents Table of Contents Ask the Chatbot { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type" : "Question", "name" : " What are immune checkpoint inhibitors (ICIs)? ", "acceptedAnswer" : { "@type" : "Answer", "text" : "Immune checkpoint inhibitors (ICIs) are drugs that enhance the immune systemu2019s ability to detect and attack cancer cells by blocking proteins known as checkpoints, which help regulate immune activity." } } , { "@type" : "Question", "name" : " How did the concept of immune checkpoint inhibitors develop? ", "acceptedAnswer" : { "@type" : "Answer", "text" : "The concept of leveraging the immune system for the treatment of disease emerged in the mid-20th century, facilitated by the discovery of molecules involved in immune surveillance. By the late 1990s researchers understood the role of regulatory molecules such as CTLA-4, PD-1, and PD-L1 in limiting T-cell activity, which cancer cells exploit to evade detection." } } , { "@type" : "Question", "name" : " What was the first immune checkpoint inhibitor (ICI) approved by the U.S. Food and Drug Administration (FDA)? ", "acceptedAnswer" : { "@type" : "Answer", "text" : "Ipilimumab was the first immune checkpoint inhibitor (ICI) approved by the FDA. It was approved in 2011 for the treatment of advanced melanoma." } } , { "@type" : "Question", "name" : " What challenges have immune checkpoint inhibitors (ICIs) introduced to cancer care? ", "acceptedAnswer" : { "@type" : "Answer", "text" : "Although highly effective in some patients, immune checkpoint inhibitors (ICIs) have introduced challenges for cancer care, particularly in the area of immune-related toxicities, which are highly variable and unpredictable. Other issues associated with ICIs center on treatment cost and access." } } ] } Top Questions What are immune checkpoint inhibitors (ICIs)? Immune checkpoint inhibitors (ICIs) are drugs that enhance the immune system’s ability to detect and attack cancer cells by blocking proteins known as checkpoints, which help regulate immune activity.

　　How did the concept of immune checkpoint inhibitors develop? The concept of leveraging the immune system for the treatment of disease emerged in the mid-20th century, facilitated by the discovery of molecules involved in immune surveillance. By the late 1990s researchers understood the role of regulatory molecules such as CTLA-4, PD-1, and PD-L1 in limiting T-cell activity, which cancer cells exploit to evade detection.

　　What was the first immune checkpoint inhibitor (ICI) approved by the U.S. Food and Drug Administration (FDA)? Ipilimumab was the first immune checkpoint inhibitor (ICI) approved by the FDA. It was approved in 2011 for the treatment of advanced melanoma.

　　What challenges have immune checkpoint inhibitors (ICIs) introduced to cancer care? Although highly effective in some patients, immune checkpoint inhibitors (ICIs) have introduced challenges for cancer care, particularly in the area of immune-related toxicities, which are highly variable and unpredictable. Other issues associated with ICIs center on treatment cost and access.

　　immune checkpoint inhibitor (ICI), class of drugs that enhance the ability of the immune system to detect and attack cancer cells. Immune checkpoint inhibitors (ICIs) are so-named because they block proteins known as checkpoints, which normally help regulate the immune system by preventing it from becoming overactive and damaging healthy cells. The development of ICIs is considered one of the most significant breakthroughs in cancer treatment since the advent of chemotherapy. The concept of immune surveillance—the idea that the immune system can recognize and destroy cancer cells—emerged in the mid-20th century. By the late 1990s researchers had elucidated the role ...(100 of 583 words)

　　Unlock the full article Access our trusted destination for facts and information 7-Day Free Trial, No Ads, Unlimited Access, Exclusive Content Subscribe Today