Phase II study of capecitabine and trastuzumab combination chemotherapy in patients with HER2 overexpressing metastatic breast cancers resistant to both anthracyclines and taxanes.

Purpose: The purpose of this study was to investigate the activity of capecitabine and trastuzumab in patients with HER2-overexpressing metastatic breast cancer resistant to both anthracyclines and taxanes.

Method: From June 2003 and May 2006, 40 female patients with measurable or assessable metastatic breast cancer were enrolled and data from 38 patients were reviewed extramurally and analyzed. Patients were treated with weekly trastuzumab given at a dose of 2 mg/kg/day over 90 min (4 mg/kg/day on the first infusion) and capecitabine given at a dose 1,657 mg/m(2)/day during 21 days with a subsequent pause of 7 days. This cycle was repeated every 28 days. The primary endpoint was overall survival and secondary endpoints were progression-free survival and response rate.

Result: A median of 4.5 cycles (range 1-9 cycles) were delivered. The median age was 53 (range 30-69 years). Median overall survival and progression-free survival was 22.3 and 4.1 months, respectively. Survival rate at 1 and 2 year was 81.6 and 47.4%, respectively. Response rate was 18.4% (95% CI, 7.7-34.3%). All evaluable patients have responded with two CR (5.3%), 5 PR (13.2%), 20 SD (52.6%), 8 PD (21.1%) and 3 NE (7.9%). Regarding the hematological toxicities, grade 1/2/3 neutropenia, grade 1/2 anemia, grade 1 thrombocytopenia and grade 1/2 liver dysfunction were also common. No treatment-related death was reported.

Conclusion: The combination of capecitabine and trastuzumab is active and well-tolerated in patients with HER2-overexpressing breast caner resistant to both anthracyclines and taxanes.