Evolution of capecitabine dosing in breast cancer

In the United States, poor patient tolerability of the standard capecitabine dosing regimen (1250 mg/m² twice daily on days 1-14 administered every 21 days) limits the established benefit of the agent. The observation that patient tolerability improves and efficacy is maintained with lower doses led to the investigation of various doses and schedules in patients with metastatic breast cancer. Capecitabine monotherapy in daily doses of 1000-2560 mg/m² or in combination with a taxane in daily doses of 825-1250 mg/m² has confirmed that tolerability improves and efficacy is maintained with lower-than-standard doses. Similar results have been observed with various dosing schedules, including continuous administration and 28-day, 7-day, and 7-days-on/7-days-off cycles. These findings suggest that capecitabine administered in a variety of doses and schedules might be a viable alternative to anthracycline-containing regimens as first- or second-line treatment in patients with metastatic breast cancer.