capecitabine + ropidoxuridine

Capecitabine + ropidoxuridine is an investigational combination of two oral small molecule drugs used as radiosensitizing agents in cancer therapy. Capecitabine is a prodrug of 5-fluorouracil (5-FU), an antimetabolite that inhibits DNA synthesis by interfering with thymidylate synthase after conversion to 5-FU within tumor cells[7][8]. Ropidoxuridine (IPdR) is a halogenated pyrimidine analog and prodrug of iododeoxyuridine (IUdR), which incorporates into DNA during replication and increases the sensitivity of cancer cells to radiation by disrupting DNA repair mechanisms[4][5]. The combination has been studied primarily in rectal adenocarcinoma as part of chemoradiotherapy regimens, aiming to enhance the efficacy of radiotherapy. Clinical development has included phase I trials; however, significant toxicity such as treatment-related typhlitis has been reported, leading to early trial termination for this specific regimen[1][3][6].