Weekly topotecan: an alternative to topotecan's standard daily x 5 schedule?

Relapsed ovarian cancer and small cell lung cancer are frequently treated with topotecan (Hycamtin), for which the standard dose and schedule are 1.5 mg/m(2) daily for five consecutive days every 3 weeks. Clinical experience has shown that this dose and schedule may be too toxic for some patients, especially those who have been heavily pretreated with platinum-based therapeutics, and it has been suggested that starting doses of topotecan be reduced to 1.0-1.25 mg/m(2)/d. Recently, multiple clinical trials have begun to evaluate the feasibility and preliminary antitumor activity of an alternative schedule based on weekly administration of topotecan. The potential benefits of weekly administration include not only reduced toxicity without significant compromise of antitumor activity, but also greater patient convenience and quality of life and greater potential for developing new topotecan-containing combination therapies. This report reviews the rationale for a weekly schedule, as well as a growing base of emerging clinical data. These preliminary data suggest that weekly topotecan is active; further evaluations are planned to confirm the activity and therapeutic index and to determine optimal dosing of a weekly schedule.