irinotecan + fluorouracil + leucovorin + triacetyluridine

This is a **combination chemotherapy regimen** comprising **irinotecan**, **fluorouracil** (5-FU), **leucovorin** (folinic acid), and **triacetyluridine**. Irinotecan is a topoisomerase I inhibitor that induces DNA damage and apoptosis in cancer cells. Fluorouracil is an antimetabolite that inhibits thymidylate synthase, resulting in impaired DNA synthesis. Leucovorin enhances the binding of fluorouracil to thymidylate synthase, thereby increasing 5-FU efficacy. Triacetyluridine is an orally active prodrug of uridine, used to increase uridine levels and potentially to reduce the gastrointestinal toxicity of 5-FU by counteracting its effects in normal tissues. The combination of irinotecan, fluorouracil, and leucovorin is approved and widely used in **metastatic colorectal cancer** therapy, improving progression-free and overall survival compared to fluorouracil/leucovorin alone[1][2][3][4]. The addition of triacetyluridine is not standard in every guideline but may be used in specific settings to ameliorate 5-FU toxicity.