Phase II Study of Vinorelbine Plus Trastuzumab in HER2 Overexpressing Metastatic Breast Cancer Pretreated with Anthracyclines and Taxanes

PURPOSE: The role of first-line trastuzumab-based therapy has been firmly established in patients with human epidermal growth factor receptor-2 (HER2) positive metastatic breast cancer. In this trial, we evaluated the efficacy and safety of a vinorelbine and trastuzumab combination chemotherapy in patients who were pretreated with anthracyclines and taxanes. METHODS: Thirty-three patients with HER2 overexpressing metastatic breast cancer, all of whom had previously been treated with anthracyclines and taxanes, were included in this study. The patients were treated with 25 mg/m(2) of vinorelbine (over a 15-minute infusion) on days 1 and 8 every 3 weeks. Additionally, trastuzumab was administered at an initial dose of 4 mg/kg over 90 minutes, and was subsequently administered at weekly doses of 2 mg/kg (over 30 minutes). RESULTS: The median age of the patients was 53 years (range, 39-72 years). The overall response rate was 30.3% (10 patients; 95% confidence interval [CI], 23-57%). The median time to progression was 6.8 months (95% CI, 5.3-8.2 months). The median overall survival was 12.4 months (95% CI, 10.3-14.6 months). In the 194 cycles of treatment, the incidence rates of grade ≥3 neutropenia and anemia were 7.2% and 1.0%, respectively. Neutropenic fever was detected in three cycles (1.5%). The non-hematological toxicities were not severe: grade 1 or 2 nausea or vomiting was detected in 15.2%, and grade 2 neuropathy was noted in 6.1% of patients. None of the patients experienced any serious cardiac toxicity, and no treatment-related deaths occurred. CONCLUSION: These results show that a combination chemotherapy consisting of vinorelbine and trastuzumab is useful in patients with HER2-overexpressing metastatic breast cancer who were pretreated with anthracyclines and taxanes, with a favorable toxicity profile.