A phase I study of escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) given in combination with high-dose carboplatin was conducted to identify the antitumor efficacy and maximum tolerated dose of paclitaxel in patients who had received sequential cycles of paclitaxel/cyclophosphamide as prior treatment for ovarian carcinoma. Eighteen patients with advanced ovarian cancer were treated in this study. Induction therapy consisted of two cycles of cyclophosphamide 3.0 g/m2 plus high-dose paclitaxel 300 mg/m2 plus filgrastim and leukapheresis to harvest peripheral blood progenitor cells, followed by four courses of rapidly cycled high-dose carboplatin with planned dose escalation of paclitaxel (150, 200, 250, and 300 mg/m2) rescued with peripheral blood progenitor cells. The study was amended after accrual of 11 patients, and the remaining seven patients received a single cycle of induction therapy with paclitaxel/cyclophosphamide, followed by four courses of rapidly cycled high-dose carboplatin with planned dose escalation of paclitaxel through levels 200 and 250 mg/m2. All 18 patients have completed therapy. Of the 15 who are evaluable for response, the pathologic complete response was 33% (five of 15 patients). The administration of escalating doses of paclitaxel in combination with high-dose carboplatin following sequential cycles of paclitaxel/cyclophosphamide induction resulted in significant nonhematopoietic toxicity. Induction with a single cycle of paclitaxel/cyclophosphamide resulted in excellent progenitor cell mobilization, and significantly ameliorated the toxicity of this approach. The response rates thus far obtained are promising and warrant further evaluation.