diflomotecan diflomotecan diflomotecan (also known as bn80905) is a chemotherapeutic agent that is a topoisomerase inhibitor (top1). it varies from other camptothecin based top1 inhibitors like topotecan in having a 7-membered e-ring. the oxepan-2-one ring in the homocamptothecin analogues is more stable in plasma compared to the 6-membered lactone in camptothecin. diflomotecan was the first homocamptothecin to enter clinical trials and is currently in phase i for treating patients with sensitive small cell lung cancer (sclc). diflomotecanclinical datatrade namesdiflomotecanidentifiers iupac name (r)-5-ethyl-9,10-difluoro-5-hydroxy-4,5-dihydrooxepinoindolizinoquinoline-3,15(1h,13h)-dione cas number220997-97-7pubchem cid219023chemspider189858uniiqkt1lc4j1pchebichebi:144046chemblchembl306280chemical and physical dataformulac21h16f2n2o4molar mass398.366 g·mol−13d model (jsmol)interactive image smiles o=c1n2c(c3=nc(c=c(f)c(f)=c4)=c4c=c3c2)=cc((o)(cc)c5)=c1coc5=o inchi inchi=1s/c21h16f2n2o4/c1-2-21(28)7-18(26)29-9-12-13(21)5-17-19-11(8-25(17)20(12)27)3-10-4-14(22)15(23)6-16(10)24-19/h3-6,28h,2,7-9h2,1h3/t21-/m1/s1key:lfqcjsbxbzrmtn-oaqylsrusa-n