The objectives of this study were to determine the toxicity and phase II dose of weekly paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) administration and to describe our initial experience with salvage weekly intravenous paclitaxel in women with advanced recurrent ovarian carcinoma. We conducted a phase I trial of paclitaxel administered as a 1-hour infusion in advanced ovarian cancer patients, using doses of 40 to 100 mg/m2/wk. As a follow-up study, we retrospectively reviewed the medical records of 45 patients with advanced, recurrent epithelial ovarian cancer treated between January 1, 1996, and October 30, 1996, with single-agent weekly intravenous paclitaxel (60 to 100 mg/m2, 1-hour infusions). Response for patients with measurable disease was based on improvements in physical examination or a greater than 50% reduction in the perpendicular diameters of all lesions in serial computed tomography. Since many of the patients did not have measurable disease, some evaluations of response to therapy were based on decline in serum carbohydrate antigen-125 according to published criteria. In our phase I study, 18 patients received 194 weekly courses of therapy at doses of 40, 50, 60, 80, and 100 mg/m2. The dose-limiting toxicity was defined as two or more patients with treatment delay or grade 3 toxicity (National Cancer Institute common toxicity criteria) at the same dose level. Treatment was delayed in two of three patients (for neutrophil counts < 1,500/microL at the 100 mg/m2 dose level); therefore, a phase II dose of 80 mg/m2/wk is recommended. No patient required hospitalization for neutropenia/fever. In the retrospective cohort review, the median patient age was 55 years (range, 32 to 79 years). All patients were heavily pretreated with multiple systemic chemotherapy regimens, including paclitaxel, with a median of four regimens (range, one to eight) before receiving weekly paclitaxel. Patients received a median of nine cycles of weekly paclitaxel (range, three to 37), with a median interval of 8 months (range, 1 to 32 months) between the last paclitaxel treatment and the institution of weekly therapy. Response was noted in 13 of 45 (28.9%) patients, with a median of seven treatments to achieve response. Chemotherapy was generally well tolerated, with treatments completed on a weekly schedule and only one hospitalization for nadir fever. We conclude that weekly intravenous paclitaxel is an active and well-tolerated regimen in heavily pretreated women with recurrent ovarian carcinoma. Prior therapy with paclitaxel does not preclude response to this regimen. A phase II trial of weekly paclitaxel in paclitaxel-refractory patients is under way.