Objective. Topotecan and carboplatin are active in relapsed ovarian cancer, but attempts to combine these agents are limited by myelotoxicity. This phase I/II trial combined weekly topotecan, which is less myelosuppressive than the standard 5-day regimen, with carboplatin in patients with potentially platinum-sensitive relapsed ovarian or peritoneal carcinoma (PS-OVCa/PCa). Methods. Eligible patients had PS-OVCa/PCa, performance status 0-2, and normal bone marrow, renal, and hepatic functions. On day 1 of a 21-day cycle, patients received carboplatin (area under the curve [AUC] 5) followed by topotecan 2.0 mg/m2, both via 30-min intravenous infusion. Topotecan 2.0 mg/m2 also was administered on days 8 and 15. Treatment was withheld for neutropenia or thrombocytopenia on day 8 or 15. Dose escalation was planned. Results. Seventeen patients received a total of 115 (median, 6)-cycles of chemotherapy. With carboplatin AUC 4, neutropenia prevented dose escalation of topotecan; hematologic toxicity caused 34/105 (32%) weekly treatments to be withheld. However, carboplatin could be dose escalated to AUC 5 when the day 15 dose of topotecan was withheld. In the intent-to-treat population, there were 4 (24%) complete and 9 (53%) partial responses, 2 (12%) patients (at the carboplatin AUC 4 dose) with stable disease, and 2 (12%) nonevaluable patients. Conclusion. Carboplatin (AUC 5) on day 1 in combination with topotecan 2.0 mg/m2 on days 1 and 8 of a 21-day cycle is well tolerated and active in patients with PS-OVCa/PCa. A phase II trial comparing this with other carboplatin therapeutic doublets in patients with recurrent ovarian cancer is warranted. Objective. Topotecan and carboplatin are active in relativizing ovarian cancer, but trying to combine these agents are limited by myelotoxicity. This phase I / II trial combined weekly topotecan, which is less myelosuppressive than the standard 5-day regimen, with carboplatin in patients with potentially volunteer had PS-OVCa / PCa, performance status 0-2, and normal bone marrow, renal, and hepatic functions. On day 1 of a 21-day cycle, patients received carboplatin (area under the curve [AUC] 5) were topotecan 2.0 mg / m2, both via 30-min intravenous infusion. Topotecan 2.0 mg / m2 also was administered on days 8 and 15. Treatment was withheld for neutropenia or thrombocytopenia on day 8 or 15. Dose escalation was planned. Results Seventeen patients received a total of 115 (median, 6) -cycles of chemotherapy. With carboplatin AUC 4, neutropenia dose escalation of topotecan; hematologic t However, carboplatin could be dose escalated to AUC 5 when the day 15 dose of topotecan was withheld. In the intent-to-treat population, there were 4 (24% Carboplatin (AUC 5) on day 1 in combination (2%) patients (at the carboplatin AUC 4 dose) with stable disease, and 2 with topotecan 2.0 mg / m2 on days 1 and 8 of a 21-day cycle is well tolerated and active in patients with PS-OVCa / PCa. A phase II trial comparing this with other carboplatin therapeutic doublets in patients with recurrent ovarian cancer is warranted .