paclitaxel + carboplatin + cisplatin + pemetrexed

This is a **combination chemotherapy regimen** consisting of four cytotoxic agents: paclitaxel, carboplatin, cisplatin, and pemetrexed. All four are small molecule chemotherapy drugs commonly used in the treatment of various solid tumors, especially non-small cell lung cancer (NSCLC) and mesothelioma. **Paclitaxel** is a microtubule inhibitor that stabilizes microtubules, preventing cell division. **Carboplatin** and **cisplatin** are platinum-containing compounds that form DNA adducts, inhibiting DNA replication and transcription, and leading to apoptosis. **Pemetrexed** is a folate antimetabolite that inhibits several enzymes involved in purine and pyrimidine synthesis, disrupting DNA and RNA synthesis and cell proliferation. This particular four-drug combination is not standard as a named regimen but each of these drugs is well established as part of various platinum-doublet or triplet regimens for advanced non-squamous NSCLC and other cancers[1][2][3][7][8]. The four-drug combination may be considered in a research or salvage therapy context due to cumulative toxicity.