Objective. To investigate weekly topotecan in heavily pretreated patients with recurrent ovarian cancer. Methods. The records of patients with recurrent epithelial ovarian cancer who were treated with weekly topotecan after failure of ≥ 1 prior regimen were reviewed. Patients received topotecan (median starting dose 2.5 mg/m2) on days 1, 8, and 15 of a 28- day cycle. Antitumor response was assessed after 2 cycles by serial CA- 125 levels. Results. Thirty-five heavily pretreated patients received a mean of 5 cycles of topotecan (range, 1- 13 cycles)- . Thirty-two patients had definable platinum sensitivity (16 sensitive, 8 resistant, 8 refractory). Median age was 56 years. A total of 177 cycles (534 weeks) of topotecan was administered. Hematologic toxicity was generally mild, and no grade 4 toxicities were observed. Grade 3 hematologic toxicity, including leukopenia, neutropenia, thrombocytopenia, and anemia, was observed in 2, 2, 1, and 0 patients, respectively. No patients experienced grade 3 or 4 nonhematologic toxicity. Based on serial CA- 125 measurements, there were 1 (3% ) complete and 5 (15% ) partial responses, with 1 of the partial responses in a patient with platinum-refractory disease. Stable disease was reported in 13 (38% ) patients, including 5 patients with platinum-resistant/refractory disease. Conclusion. Weekly topotecan demonstrates activity and is well tolerated compared with historical data with the standard 5- day schedule. Higher doses may be warranted because of the high tolerability shown for weekly topotecan. Weekly topotecan may be an appropriate treatment option for patients with recurrent ovarian cancer, especially heavily pretreated patients who might require dosing schedules with improved tolerability. Methods for investigating weekly topotecan in heavily pretreated patients with recurrent ovarian cancer. Methods. The records of patients with recurrent epithelial ovarian cancer who were treated with weekly topotecan after failure of ≥ 1 prior regimen were reviewed. Patients received topotecan (median starting dose 2.5 mg / m2) on days 1, 8, and 15 of a 28- day cycle. Antitumor response was assessed after 2 cycles by serial CA- 125 levels. Results. Thirty-five heavily pretreated patients received a mean of 5 cycles of topotecan Thirty-two patients had definable platinum sensitivity (16 sensitive, 8 resistant, 8 refractory). Median age was 56 years. A total of 177 cycles (534 weeks) of topotecan was administered. Hematologic toxicity Grade 3 hematologic toxicity, including leukopenia, neutropenia, thrombocytopenia, and anemia, was observed in 2, 2, 1, and 0 patients, respectively. No patients experien Based on serial CA-125 measurements, there were 1 (3%) complete and 5 (15%) partial responses, with 1 of the partial responses in a patient with platinum-refractory disease. Stable disease Weekly topotecan demonstrates activity and is well tolerated compared with historical data with the standard 5-day schedule. Higher doses may be warranted because of the high tolerability shown for weekly topotecan. Weekly topotecan may be an appropriate treatment option for patients with recurrent ovarian cancer, especially heavily pretreated patients who might require dosing schedules with improved tolerability.