5-fluorouracil + bevacizumab + cetuximab + leucovorin + oxaliplatin

This is a combination regimen consisting of five agents used in the treatment of advanced or metastatic colorectal cancer. The components are: - **5-fluorouracil** (5-FU): a pyrimidine analog and antimetabolite that inhibits DNA synthesis by incorporating into DNA and RNA, leading to cell death. - **Bevacizumab**: a monoclonal antibody targeting vascular endothelial growth factor A (VEGF-A), inhibiting angiogenesis required for tumor growth. - **Cetuximab**: a chimeric monoclonal antibody against the epidermal growth factor receptor (EGFR), blocking downstream signaling pathways involved in cell proliferation and survival. - **Leucovorin** (folinic acid): enhances the cytotoxic effects of 5-fluorouracil by stabilizing its binding to thymidylate synthase. - **Oxaliplatin**: a platinum-based chemotherapeutic agent that forms DNA crosslinks, inhibiting DNA replication and transcription. This combination is not standard but has been studied in clinical trials for metastatic colorectal cancer. The addition of both bevacizumab and cetuximab to chemotherapy regimens has not shown superior efficacy compared to regimens with only one biologic agent, and concurrent use is generally not recommended due to lack of added benefit and increased toxicity[3][5]. Each component targets different mechanisms critical for tumor progression.