cisplatin + erlotinib + pemetrexed

This is a combination regimen consisting of three drugs—cisplatin, erlotinib, and pemetrexed—used primarily in the treatment of certain cancers, most notably non-small cell lung cancer (NSCLC). - **Cisplatin** is a platinum-based chemotherapeutic agent that forms DNA crosslinks and inhibits DNA synthesis and function, leading to apoptosis in rapidly dividing cells. - **Erlotinib** is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that blocks EGFR signaling pathways involved in tumor cell proliferation and survival. - **Pemetrexed** is an antifolate antineoplastic agent that disrupts folate-dependent metabolic processes essential for cell replication by inhibiting multiple enzymes involved in purine and pyrimidine synthesis[1][2][3][4][5]. This combination targets cancer cells through complementary mechanisms—DNA damage (cisplatin), inhibition of growth signaling (erlotinib), and disruption of nucleotide synthesis (pemetrexed)—and has been investigated or used as a first-line or subsequent therapy for advanced or metastatic NSCLC, particularly non-squamous subtypes[1][2][3].