topotecan + etoposide

Topotecan + etoposide is a combination chemotherapy regimen consisting of two small molecule antineoplastic agents, topotecan and etoposide. This combination has been studied as a platinum-free regimen for the first-line treatment of extensive disease small cell lung cancer (ED SCLC). Topotecan is a topoisomerase I inhibitor that induces DNA damage by stabilizing the cleavable complex between DNA and topoisomerase I, leading to replication arrest and apoptosis. Etoposide is a semisynthetic podophyllotoxin derivative that inhibits DNA synthesis by forming a complex with topoisomerase II and DNA, causing double-stranded breaks in DNA and preventing repair, which leads to cell death. The combination exploits sequential inhibition of both type I and type II topoisomerases to enhance cytotoxicity against rapidly dividing tumor cells[1][2][4].