See package insert for further information. 18.4 Etoposide Source and Pharmacology Etoposide ((VePesid®, Etopophos®,VP -16) NSC #141540 (112005)) is asemisynthetic der ivative of podophyllotoxin that forms a complex with topoisomerase II and DNA which results in single and double strand DNA breaks. Its main effect appears to be in the S and G2 phase of the cell cycle.