OBJECTIVE: To determine the nature and degree of toxicity, response rate, quality of life (QOL), and progression-free interval in women with platinum-resistant refractory ovarian or peritoneal cancer receiving weekly topotecan and gemcitabine. METHODS: A Phase II trial of gemcitabine 800 mg/m(2) and topotecan 3.0 or 2.5 mg/m(2) administered on days 1 and 8 of a 21-day cycle was conducted. Response was assessed by RECIST criteria. Quality of life was assessed with FACT-O. RESULTS: Twenty-three patients were enrolled in the study and all were evaluable. One patient was later found to be ineligible due to a concurrent endometrial malignancy, but remains part of the analysis. Sixteen patients (70%) had measurable disease at baseline and 7 (30%) had elevated CA125 only. The median number of prior regimens was 1, range 1-4 and median number of prior cycles was 8, range 3-39. The first 6 patients received topotecan at a dose of 3.0 mg/m(2), but because of dose delays and need for GCSF the dose of topotecan was lowered to 2.5 mg/m(2). There were 4 (17%) partial responses, but only two (9%) were confirmed prior to progression; and 8 (35%) had stable disease. Toxicity was acceptable with only 8 of the 107 cycles given requiring a dose reduction. Four patients (17%) were taken off the study for toxicity, two at the higher dose and two at the lower dose. Median time to recurrence was 3.0 months and median overall survival was 12.6 months. QOL did not differ with subsequent cycles as compared to baseline. CONCLUSION: The combination of weekly topotecan and gemcitabine is well tolerated, but best response rate is 17%, and confirmed response is only 9%, which is not significantly better than single agent gemcitabine or topotecan. These results do not provide compelling evidence for the combination of weekly gemcitabine and topotecan as a promising therapy.