Background: The observed activity of cisplatin in breast cancer and its unattractive toxicity profile in palliative treatment warranted further study of platinum analogues in this disease.
Patients and methods: Sixty-two patients with recurrent or metastatic breast cancer, 61 of whom had been previously treated with chemotherapy, were randomly assigned to therapy with either iproplatin (n = 32) or carboplatin (n = 30). Both platinum analogues were administered intravenously, iproplatin at a dose of 240 mg/m2 every 4 weeks and carboplatin at a dose of 450 mg/m2 every 5 weeks.
Results: Only two patients responded to iproplatin (7%) for durations of 21 and 61 weeks, and one patient responded to carboplatin (3%) for a duration of 64 weeks. All responses were complete. At the given dose schedules carboplatin was more myelosuppressive than iproplatin. Non-hematologic toxicities included nausea and vomiting (93% vs. 90%), diarrhea (20% vs. 10%) and hemorrhage (16% vs. 10%) for iproplatin and carboplatin, respectively. Two patients developed alopecia with carboplatin. No renal toxicity was observed.
Conclusions: Both iproplatin and carboplatin have limited activity in previously treated women with advanced breast cancer when given in conventional dosages.