Paclitaxel Administered Weekly in Patients with Docetaxel-Resistant Metastatic Breast Cancer: A Single-Center Study

AIMS AND BACKGROUND: We evaluated retrospectively the efficacy and toxicity of paclitaxel in patients with docetaxel-resistant metastatic breast cancer. STUDY DESIGN: Paclitaxel (80 mg/m2) was administered weekly to 44 patients who had previously received chemotherapy regimens for metastatic breast cancer. All patients had progressive disease in spite of having received docetaxel therapy. RESULTS: Treatment was repeated until there was evidence of disease progression. Objective responses were obtained in 14 of 44 assessable patients (31.8%; 95% confidence interval, 17.5-46.1). Fourteen patients had partial responses; none responded completely. Seven of 14 responders had primary resistance to docetaxel therapy. The median duration of response was 6.1 months (range, 2.1-12.7). The median time to progression was 5.0 months. Clinically severe adverse events (grade 3 or 4) included neutropenia (27.2%), leukopenia (25.0%), neuropathy-sensory (13.6%), febrile neutropenia (6.8%), anemia (2.2%), constipation (2.2%), and edema (2.2%). Treatment was generally well tolerated and could be continued on an out-patient basis. CONCLUSIONS: Weekly paclitaxel is effective in patients with docetaxel-resistant metastatic breast cancer. This observation suggests partial cross-resistance between paclitaxel and docetaxel. There was no evidence for additive cumulative toxic effects of the two taxanes.