Treatment of advanced breast cancer with sterically stabilized liposomal doxorubicin: results of a multicenter phase II trial.

Abstract

PURPOSE: A multicenter phase II study to determine the activity and toxicity of Caelyx (Doxil; Sequus Pharmaceuticals Inc, Menlo Park, CA) in patients with metastatic breast cancer. PATIENTS AND METHODS: Seventy-one patients with stage IV breast cancer were treated with Caelyx at doses of 45 to 60 mg/m2 every 3 to 4 weeks for a maximum of six cycles. Twenty-eight patients had received prior chemotherapy with a nonanthracycline regimen. Fifty-two patients had disease at multiple sites. Hepatic and pulmonary disease were the predominant metastatic site in 50 patients. Response was assessable in 64 cases. RESULTS: Sixteen patients achieved a partial response and a complete response (overall response rate, 31%; (95% confidence interval, 20% to 43%). Twenty patients (31%) had stable disease on treatment. Neutropenia > or = grade 3 occurred in 10% of cycles (27% of patients) and mucositis > or = grade 3 in 10% of cycles (32% of patients). Significant alopecia was rare and routine prophylactic antiemetics were not required. At doses of 60 mg/m2 every 3 weeks, seven of 13 patients had > or = grade 3 skin toxicity; overall, this toxicity complicated 25% of treatment cycles. The incidence of > or = grade 3 skin toxicity was greatly reduced at doses of 45 mg/m2 every 4 weeks, occurring in five of 32 patients and affecting only 5% of 126 treatment cycles. CONCLUSION: Caelyx is an active agent in advanced breast cancer with a safety profile that differs markedly from nonliposomal doxorubicin. A regimen of 45 mg/m2 every 4 weeks was well tolerated in this cohort of women with advanced poor-prognosis breast cancer. The mild myelosuppression seen with this regimen would favor its use in combination chemotherapy.