5-fluorouracil + OK-432 + mitomycin C + uracil + tegafur

This is a multi-agent combination regimen consisting of five components: - **5-fluorouracil (5-FU):** A pyrimidine antimetabolite that inhibits thymidylate synthase, disrupting DNA synthesis and leading to cell death, primarily in rapidly dividing cancer cells. - **OK-432 (Picibanil):** An immunotherapeutic agent derived from a low-virulence strain of Streptococcus pyogenes, used as an immune modulator to stimulate the host's immune response against tumors. - **Mitomycin C:** An antitumor antibiotic that acts as an alkylating agent, cross-linking DNA and inhibiting DNA synthesis. - **Uracil:** A naturally occurring pyrimidine base; when combined with tegafur, it inhibits the degradation of 5-FU by dihydropyrimidine dehydrogenase, increasing its bioavailability and enhancing its antitumor effect. - **Tegafur:** An oral prodrug of 5-FU designed for improved absorption; it is converted in vivo to active 5-FU. This combination has been studied as adjuvant therapy for colorectal cancer (colon and rectal), aiming to combine cytotoxic chemotherapy with immunomodulation. The regimen leverages both direct tumoricidal effects and stimulation of anti-tumor immunity. Clinical trials have shown these combinations are generally well tolerated but did not significantly prolong survival compared to other regimens[1][4][6].