A dose-finding study was performed in 27 ovarian cancer patients to define the maximum tolerated dose of a 3-hour infusion of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in combination with a fixed dose of carboplatin. The median age of the patients was 55 years (age range, 30 to 74 years), the median performance status was 0 (range, 0 to 2), and the sizes of tumors residual to first surgery were identified as > or = 1 cm (14 patients) or less than 1 cm (13 patients). All patients received carboplatin at a fixed dose of 300 mg/m2 over 1 hour. Paclitaxel was administered as a 3-hour infusion at five dose levels, starting at 150 mg/m2 and increasing in 25 mg/m2 increments to 250 mg/m2. In the absence of toxicity, courses were repeated every 4 weeks for a total of six cycles. Mild emesis, general alopecia, and moderate myalgias occurred. Hypersensitivity and cardiotoxicity were observed in 7.4% and 14.8% of patients, respectively. Moderate peripheral neuropathy was experienced by 30% of patients. Grade 3 and 4 neutropenia lasted less than 7 days; no patients required hospitalization for sepsis or febrile neutropenia, and no supportive treatment with granulocyte/granulocyte-macrophage colony-stimulating factor was needed. Twenty-one patients were evaluable for response. Overall response rate (complete response+partial response) was 81%, and responses were observed at all paclitaxel dose levels. The maximum tolerated dose was not achieved. In conclusion, with a fixed dose (300 mg/m2) of carboplatin, paclitaxel can be administered by 3-hour infusion at 250 mg/m2 with manageable toxicity and no supportive care is needed.