Weekly Paclitaxel in the Treatment of Advanced or Metastatic Breast Cancer Previously Treated or Not Treated with Docetaxel: A Phase II Study

BACKGROUND: Paclitaxel has been approved for 3-weekly administration in Japan. Recent reports suggest that weekly paclitaxel can achieve a higher tumor response and lower toxicity. METHODS: This study was designed to investigate the usefulness and tolerability of weekly paclitaxel by 1-hour infusion in patients with metastatic breast cancer who were previously treated with docetaxel or other anticancer agents. RESULTS: Thirty-five patients were enrolled. The overall response rate was 41.2% (14/34, 95% confidence interval: 24.6-59.3%). The median time to progression and the median survival time were 218.5 and 624 days, respectively. One patient developed dyspnea, probably induced by a hypersensitivity reaction. The most common hematological toxicities were leukopenia and neutropenia, although no patients developed grade 4 leukopenia or neutropenia and G-CSF support was not required. CONCLUSIONS: Weekly paclitaxel could be safely administered and achieved a relatively high response rate. Weekly paclitaxel would be a good candidate second-line therapy for recurrent or advanced breast cancer.