Mitomycin C plus Capecitabine (MiXe) in Anthracycline- and Taxane-pretreated Metastatic Breast Cancer. A Multicenter Phase II Study

Background: Capecitabine is considered the treatment of choice for anthracycline- and taxane-pretreated metastatic breast cancer. Mitomycin C seems to improve the activity of capecitabine by up-regulation of thymidine phosphorylase. Patients and Methods: Fifty-five women with metastatic breast cancer previously treated with anthracycline-taxane were treated with mitomycin C 10 mg/m 2 on day 1 every six weeks and capecitabine 1000 mg/m 2 on days 2-15 every three weeks. Results: An overall response rate of 38% was found, consisting of 3 (5%) complete responses (CR) and 18 (33%) partial responses (PR); 8 patients (14%) had a stable disease (SD) for more than 4 months. The combination was well-tolerated, with the main toxicities being neutropenia, diarrhea and fatigue; other toxicities were of mild to moderate intensity without impairment in the quality of life of the patients. Conclusion: Capecitabine is confirmed as the drug of choice in the treatment of anthracycline- and taxane-pretreated metastatic breast cancer and its combination with mitomycin appears to improve its efficacy.