BCG vaccine + cyclophosphamide + fluorouracil + methotrexate

This is a multi-agent combination regimen consisting of the BCG vaccine (Bacillus Calmette-Guérin) and three chemotherapeutic agents—cyclophosphamide, fluorouracil (5-fluorouracil), and methotrexate. - **BCG vaccine** is an attenuated live strain of Mycobacterium bovis used as an intravesical immunotherapy for non-muscle invasive bladder cancer. It stimulates a local immune response in the bladder, leading to tumor cell rejection by activating macrophages, leukocytes, and other immune cells[4][8]. - **Cyclophosphamide** is an alkylating agent that crosslinks DNA strands, inhibiting DNA replication and leading to cell death[9]. - **Fluorouracil (5-FU)** is a pyrimidine analog that inhibits thymidylate synthase, disrupting DNA synthesis in rapidly dividing cells[9]. - **Methotrexate** is an antimetabolite that inhibits dihydrofolate reductase, blocking folic acid metabolism required for DNA synthesis[9]. The combination leverages both immunotherapeutic effects from BCG and cytotoxic effects from chemotherapy. While CMF (cyclophosphamide + methotrexate + fluorouracil) has established use in breast cancer and other malignancies[6][7][9], there are no widely recognized regimens or approvals specifically combining all four agents with BCG for any indication based on current evidence.