Pirarubicin in combination chemotherapy for metastatic breast cancer

Pirarubicin is an anthracycline with broad antitumor activity, and without significant cardiotoxicity in preclinical and early clinical trials. We treated 40 evaluable patients with metastatic breast cancer and no prior exposure to chemotherapy with 5-fluorouracil, pirarubicin, and cyclophosphamide at 21-day intervals until reaching cumulative doses of 800 mg/m² of pirarubicin, or the development of progressive disease. The median age was 56 years and the median performance status, 1. Seventeen patients had prior hormone therapy and 12 had prior radiotherapy. The median number of metastatic sites was three, with 11 patients having less than three sites. Twelve patients were premenopausal. The median disease-free interval was 6 months. Four patients achieved a complete remission and 21 a partial remission, for an overall response rate of 63%. The median response duration was 8 months and the median time to progression for all patients was 9 months. The median survival has not been reached, but will exceed 13 months. Gastrointestinal toxicity was minimal to moderate, whereas myelosuppression was severe. Complete hair loss was observed by only 58% of patients. There were two episodes of mild congestive heart failure at high cumulative doses of pirarubicin; both were controlled with medical treatment. This three-drug combination containing pirarubicin is effective in treating metastatic breast cancer, with less severe toxicity than other anthracycline-containing combinations.