Based on the efficacy of pegylated liposomal doxorubicin (PLD) in relapsed ovarian cancer, we are conducting a phase III study comparing carboplatin plus either paclitaxel or PLD as first-line therapy in advanced ovarian cancer. Because of limited phase I and II data on PLD plus carboplatin in this setting, we conducted an interim activity analysis. Patients with stage 1c-IV epithelial ovarian cancer were randomized to carboplatin AUC 5 plus either paclitaxel 175 mg/m(2) or PLD 30 mg/m(2) every 3 weeks for 6 cycles. The interim activity analysis was planned according to a single-stage phase II design with an auspicated 50% response rate; 50 patients eligible for response assessment were required. Response was defined according to RECIST (Response Evaluation Criteria in Solid Tumors). A complete response was achieved in 14 patients (28%) and a partial response in 20 (40%), which produced an overall response rate of 68%. The activity exceeded the minimum required for study continuation. Stable disease was reported in an additional 10 patients (20%). The adopted schedule of PLD plus carboplatin demonstrates activity as a first-line treatment for advanced ovarian cancer.