The purpose of this study was to evaluate the combination of cisplatin and vinorelbine (PVn) for relapsed and chemotherapy-pretreated metastatic breast cancer. Twenty-three patients with metastatic breast cancer and prior chemotherapy were entered in a phase II study between June 1993 and December 1994. Eleven patients were premenopausal and 12 were postmenopausal. Follow-up data up to June 1997 are presented. All patients received cisplatin at a dose of 90 mg/m2 divided over 3 days as 30 mg/m2 infused over 4 hours. Intravenous vinorelbine 25 mg/m2 was given on days 1 and 8 or 15 according to patients' blood counts. Cycles were given every 3 to 4 weeks. An overall response rate of 61% (16/23 patients) was observed. Complete remission was obtained in six patients (26%) and partial remission was obtained in nine patients (35%). The duration of response ranged from 3 to 9 months, with an average of 4 months. Stable disease was noted in 29.1% and progressive disease in 8.3%. Overall survival at 12 months was 50%, and at 36 months it was 8%. Five of 12 patients (42%) who had prior doxorubicin therapy responded well to cisplatin-vinorelbine. Of those 12, seven were refractory and progressive on a doxorubicin-containing regimen, one had complete remission, and four had partial remission. Hematologic toxicity was acceptable. Treatment was delayed because of neutropenia in nine cycles (9.2%) and grade 2 leukopenia occurred in 54% of cycles. Febrile neutropenia occurred in seven cycles (7.1%), and five cycles were complicated by documented sepsis (5.1%). No treatment-related mortality occurred. Thrombocytopenia (grade 3) was seen in 27% of cycles, with no patient having a platelet count below 50,000 or bleeding episodes. Other toxicities were not major or dose-limiting. In conclusion, the combination of cisplatin and vinorelbine produced good responses: 61% response rate (16 of 23 patients) in relapsed, refractory, and heavily pretreated metastatic breast cancer, with 50% survival at 1 year, 12% at 2 years, and 8% at 3 years. In addition, a response rate of 42% (5 of 12 patients) was seen in patients resistant to anthracyclines.