Intoplicine (RP 60475) dimesylate, an antitumor derivative in the 7H-benzo[e]pyrido[4,3-b]indole series, is a DNA topoisomerase I and II inhibitor. Intoplicine dimesylate strongly binds DNA (K A = 2 x 10 5 /M) and thereby increases the length of linear DNA In Vitro With 1-hour exposure to Intoplicine dimesylate at final concentrations of 2.5 micrograms/mL and 10.0 micrograms/mL, 26% and 54% of the assessable specimens shows positive in vitro responses, respectively. With continuous exposure to Intoplicine dimesylate at concentrations of 0.25 micrograms/mL and 2.5 micrograms/mL, 16% and 71% of the assessable specimens showed positive responses, respectively. Activity is seen against breast (71%), non-small-cell lung (69%), and ovarian (45%) cancer colony-forming units at a Intoplicine dimesylate concentration of 10.0 micrograms/mL after 1-hour exposure. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo At the highest non-toxic dose (HNTD) (6 mg/kg/injection, total dose, 36 mg/kg), intoplicine dimesylate shows highly active with a T/C of 0% and a corresponding total log cell kill of 3. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:Topoisomerase I Topoisomerase II