5-fluorouracil + cyclophosphamide + leucovorin + methotrexate + prednisone

This is a combination chemotherapy regimen consisting of five drugs: - **5-fluorouracil (5-FU):** An antimetabolite that inhibits thymidylate synthase, disrupting DNA synthesis and leading to cell death, particularly in rapidly dividing cancer cells. - **Cyclophosphamide:** An alkylating agent that crosslinks DNA strands, preventing cell division and causing apoptosis. - **Leucovorin (folinic acid):** A reduced form of folic acid used to enhance the effects of 5-fluorouracil by stabilizing the binding of 5-FU’s active metabolite to thymidylate synthase; also used as a "rescue" agent with methotrexate to reduce toxicity. - **Methotrexate:** An antimetabolite and antifolate drug that inhibits dihydrofolate reductase, blocking DNA synthesis and repair. - **Prednisone:** A synthetic glucocorticoid corticosteroid with anti-inflammatory and immunosuppressive properties; it can induce apoptosis in certain cancerous lymphoid cells. This specific five-drug combination is not a standard named regimen but represents an intensive multi-agent chemotherapy protocol. Regimens containing subsets of these drugs (such as CMF—cyclophosphamide, methotrexate, fluorouracil) are established for breast cancer treatment[3][4]. The addition of leucovorin enhances 5-FU activity or mitigates methotrexate toxicity. Prednisone is commonly included in regimens for hematologic malignancies.