Phase II study of 4-weekly capecitabine monotherapy in advanced/metastatic breast cancer

Background A multicenter, phase II study was conducted to evaluate the efficacy and safety of the Japanese intermittent 4-week regimen of capecitabine in patients with advanced/metastatic breast cancer. Methods Fifty patients who had received no more than one prior chemotherapy regimen for advanced/metastatic disease were enrolled from 23 centers and received at least two 4-weekly cycles of capecitabine (828 mg/m 2 orally twice daily for 3 weeks followed by a 1-week rest period). Results The overall response rate assessed by the Independent Review Committee (standard population, n = 46) was 28.3% (95% confidence interval 16.0–43.5%), including complete responses in 6.5%. Stable disease was observed in 20 patients and maintained for more than 6 months in 10 patients. The median duration of response in 13 evaluable responders was 5.3 months. Among evaluable patients ( n = 47), median time to disease progression was 5.1 months. Median overall survival was 20.2 months. The most common treatment-related adverse events (all grades) were hand–foot syndrome (66%), nausea (26%), stomatitis (22%) and diarrhea (20%). Grade 3/4 treatment-related adverse events were seen in 23 patients (46%). The most common grade 3/4 adverse events were lymphocytopenia (22%), hand–foot syndrome (18%) and hyperbilirubinemia (10%). Conclusions Although the target overall response rate was not reached, the Japanese intermittent 4-week regimen of capecitabine was shown to be an effective and well-tolerated first- or second-line therapy for advanced/metastatic breast cancer.