OBJECTIVE: To determine the response rate, progression-free survival and toxicity associated with weekly topotecan administered to patients with platinum-sensitive recurrent epithelial ovarian (EOC) in the third-line setting. METHODS: Patients with measurable platinum-sensitive EOC following failure of second-line chemotherapy were eligible for this phase II study. All patients were initially treated with cytoreductive surgery and platinum/paclitaxel-based chemotherapy. Continuous, weekly topotecan was administered at a starting dose of 4 mg/m(2). Toxicity and efficacy were assessed at various time points after initiation of therapy. RESULTS: Twenty nine patients were enrolled in this prospective study. Toxicity was acceptable with grade 1/2 nausea being the most commonly experienced side effect (52%). Nine patients (31%) had grade 3/4 leukopenia; however, only 3 patients had febrile neutropenia. Thirteen patients had a treatment delay and six required dose reductions. Twenty two patients were evaluable for efficacy. The overall response rate for weekly topotecan was 13.6% [95% CI; -0.7-27.9%] with 1 complete response, and 2 partial responses. Twelve patients (54.5%), including 2 with minor responses, had stable disease for a median duration of 18 weeks. CONCLUSIONS: Weekly topotecan at the current schedule in the third-line setting in patients with platinum-sensitive recurrent EOC has modest clinical activity. Toxicity associated with this regimen is acceptable but growth factor support, dose reductions, or schedule alterations may need to be considered in many of these patients.