capecitabine + raltitrexed

Capecitabine + raltitrexed is an experimental combination of two small-molecule chemotherapeutic agents, both of which act as antimetabolites targeting DNA synthesis. Capecitabine is an orally administered prodrug that is converted in vivo to 5-fluorouracil (5-FU), which inhibits thymidylate synthase and disrupts DNA synthesis and repair, leading to apoptosis[3][7]. Raltitrexed is a direct and potent inhibitor of thymidylate synthase, mimicking folate cofactors required for the enzyme's activity, resulting in decreased production of thymidine triphosphate necessary for DNA replication[6][7]. Both drugs are primarily used in the treatment of advanced colorectal cancer and other gastrointestinal malignancies. The rationale for combining these agents would be to enhance inhibition of thymidylate synthase through complementary mechanisms; however, this specific combination does not appear to be standard clinical practice or widely studied together. Each drug has been combined with other agents or substituted for one another in cases where toxicity limits use[1][4].