cisplatin + pemetrexed or cisplatin + gemcitabine

This entry refers to two alternative platinum-based chemotherapy combinations used primarily in the treatment of non-small cell lung cancer (NSCLC) and other solid tumors. The regimens are: - cisplatin + pemetrexed - cisplatin + gemcitabine **Cisplatin + Pemetrexed:** This combination is approved for the initial treatment of locally advanced or metastatic non-squamous NSCLC and for malignant pleural mesothelioma that is unresectable or not suitable for curative surgery. Pemetrexed is a folate antimetabolite that inhibits multiple enzymes involved in folate metabolism and DNA synthesis, while cisplatin forms DNA crosslinks, leading to apoptosis in rapidly dividing cells[1][5][7]. This regimen is generally administered intravenously every 21 days, with supplementation of folic acid and vitamin B12 to reduce toxicity[1][8]. **Cisplatin + Gemcitabine:** This combination is also widely used as first-line therapy for advanced NSCLC. Gemcitabine is a nucleoside analog that inhibits DNA synthesis by incorporation into DNA strands during replication, causing chain termination. Cisplatin acts as described above. Both regimens are considered standard-of-care options for advanced NSCLC; choice between them may depend on tumor histology (pemetrexed combinations are preferred in non-squamous histology), patient comorbidities, toxicity profiles, and physician preference[5][8].