Daily oral topotecan: Utilization of a metronomic dosing schedule to treat recurrent or persistent solid tumors

2571 Background: Topotecan has antiangiogenic properties when administered on a metronomic schedule. This study investigated the safety, efficacy, and pharmacokinetics of oral topotecan, utilizing continuous low dose daily therapy without drug free intervals. Methods: This phase I, single-center, open-label, dose-ranging study consisted of 30-day treatment cycles of daily oral topotecan at dose levels of 0.25, 0.50, 0.75, 1.00, and 1.25 mg. Because our intent was to administer a continuous daily dose, the dose-limiting toxicity (DLT) was defined as a grade 2 adverse event. At least 3 patients (pts) were enrolled at each dose level. If 1 of 3 pts treated at a given dose level experienced a DLT, the level was expanded to 6 pts. If more than 2 of 6 pts had a DLT at that dose level, the previous dose level was considered the MTD. Results: 16 heavily pretreated pts with various solid tumors were enrolled, with an average of 4 prior regimens (range 2–11). Mean cycles received on protocol were 2 (range 1–6). 3 p...