A quinazoline folate analogue with antineoplastic activity. After transport into cells via the reduced folate carrier, raltitrexed undergoes intracellular polyglutamation and blocks the folate-binding site of thymidylate synthase, thereby inhibiting tetrahydrofolate activity and DNA replication and repair and resulting in cytotoxicity. or An anticancer drug that stops tumor cells from growing by blocking the ability of cells to make DNA. It belongs to the family of drugs called thymidylate synthase inhibitors. Also called ICI D1694.