Irinotecan (Camptosar, Campto) is a drug used for the treatment of cancer.
Irinotecan prevents DNA from unwinding by inhibition of topoisomerase 1.
In chemical terms, it is a semisynthetic analogue of the natural alkaloid camptothecin.
Its main use is in colon cancer, in particular, in combination with other chemotherapy agents. This includes the regimen FOLFIRI, which consists of infusional 5-fluorouracil, leucovorin, and irinotecan.
Irinotecan received accelerated approval by the U.S. Food and Drug Administration (FDA) in 1996 and full approval in 1998.
During development, it was known as CPT-11.
It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.