The evolving role of oral topotecan

Pharmacokinetic characteristics, efficacy, and safety of oral topotecan, a topoisomerase-I inhibitor, were evaluated in phase I and phase II clinical trials. Results of the pharmacokinetic analyses showed that orally administered topotecan has a lower peak plasma concentration (Cmax) and longer mean residence time than intravenously administered drug. Preliminary data suggest that the oral formulation has efficacy similar to that of the intravenous (IV) formulation in patients with recurrent or refractory ovarian and small-cell lung cancer. The type and degree of toxicity appeared to be related to the dosing schedule (number of days of consecutive treatment), but overall, oral topotecan appeared to be associated with less hematologic toxicity than the IV formulation.