Phase II Study of Capecitabine Plus Trastuzumab in Human Epidermal Growth Factor Receptor 2–Overexpressing Metastatic Breast Cancer Pretreated With Anthracyclines or Taxanes

Abstract

The oral fluoropyrimidine carbamate, capecitabine, is a highly active and well-tolerated treatment for metastatic breast cancer. In patients treated previously with anthracyclines and taxanes, capecitabine is an approved single-agent therapy. Trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER-2), is also highly active in HER-2-overexpressing breast cancer. We have conducted a phase II study to confirm activity and feasibility of capecitabine and trastuzumab in combination in HER-2-overexpressing advanced/metastatic breast cancer. Twenty-seven patients with HER-2-overexpressing metastatic breast cancer previously treated with anthracyclines and/or taxanes received oral capecitabine 1,250 mg/m(2) bid for 14 days followed by a 7-day rest period combined with intravenous trastuzumab 4 mg/kg body weight on day 1 (loading dose) followed by 2 mg/kg weekly. Capecitabine/trastuzumab treatment achieved objective responses in 12 patients (45%), including complete response in four patients (15%) and partial response in eight patients (30%). Disease was stabilized in an additional nine patients (33%). The median overall survival time was 28 months, and the median progression-free survival time was 6.7 months. The safety profile of the combination was favorable and predictable, with a low incidence of grade 3/4 adverse events. The most common adverse events were pain, hand-foot syndrome, and GI toxicities. Severe myelosuppression was rare and severe alopecia did not occur. These data confirm that the combination of capecitabine and trastuzumab is highly active in patients with HER-2-overexpressing anthracycline- and/or taxane-pretreated breast cancer, with only slight restrictions regarding quality of life.