Phase II study of doxorubicin versus epirubicin in advanced breast cancer

Doxorubicin and its epimerized analog epirubicin were tested at a dose of 75 mg/m2 given iv every 3 weeks to 42 patients with advanced breast cancer, 23 of whom were in relapse from prior cyclophosphamide, methotrexate, and 5-FU (CMF) chemotherapy. The median cumulative dose was 540 mg/m2 (range, 225-650) for doxorubicin and 565 mg/m2 (range, 150-600) for epirubicin. Complete plus partial response was documented in 11 of 21 patients (52%) following doxorubicin and in 13 of 21 patients (62%) following epirubicin. The median observation period was 22 months (range, 14-30); the median duration of response and the median survival were superimposable. Doxorubicin and epirubicin exhibited a superior response rate in previously untreated patients [six of eight (75%) vs eight of 11 (73%)] compared to those previously given CMF with or without endocrine therapy [five of 13 (38%) vs five of ten (50%)]. Vomiting, mucositis, and leukopenia were documented less frequently following administration of epirubicin as compared to doxorubicin. Regarding cardiac evaluation, no significant differences were evident between the two drugs. However, a significant fall in the left ventricular ejection fraction was documented in women who received doxorubicin following a cumulative dose greater than 550 mg/m2. Following completion of doxorubicin therapy at cumulative doses of 580 and 562 mg/m2, two women developed left ventricular failure at 6 and 14 months, respectively. Epirubicin appears to be an effective drug for the treatment of breast cancer and, given at equal doses, is less toxic than doxorubicin.