Phase II study of vinorelbine monotherapy in anthracycline and taxane pre-treated metastatic breast cancer.

We performed a single-institution phase II study to evaluate the efficacy and toxicities of vinorelbine monotherapy in patients previously treated with anthracyclines and taxanes. Vinorelbine was administered at a dose level of 25 mg/m² intravenously on days 1, 8, 15 and 22, every four weeks, and responses were assessed after every two cycles of treatment. All of the patients had previously been treated with anthracyclines and taxanes. A total of 26 patients were enrolled in this study between April 2004 and August 2009. The median age of the patients was 47 years (range, 37 to 71 years), and 80.8% had an Eastern Cooperative Oncology Group performance status of 0 or 1. Out of 24 evaluable patients, five partial responses were observed, giving an overall response rate of 20.8%, with a median response duration of 2.8 months. The median time to progression was 3.7 months (range, 0.5 to 22.6 months), and median overall survival duration was 10.4 months (range, 1.3 to 57.6 months). The major toxicities observed were neutropenia, anemia and peripheral neuropathy. Grade 3 or 4 hematologic toxicities included neutropenia in 18 patients (69.2%) and anemia in four patients (15.3%). Grade 1 or 2 peripheral neuropathy was observed in 11 patients (42.3%), however there were no cases of grade 3 or 4 peripheral neuropathy. The results of this study indicate that vinorelbine monotherapy was feasible regimen with manageable toxicities in patients with metastatic breast cancer who were previously exposed to anthracyclines and taxanes.