Phase II study of gemcitabine plus paclitaxel in metastatic breast cancer patients with prior anthracycline exposure

Chemotherapy provides palliation and modest prolongation of symptom-free survival in metastatic breast cancer. Taxane containing regimens are commonly considered to be among the initials in metastatic setting due to earlier use of anthracyclines in the course of breast cancer. Therefore, we conducted this Phase II study to assess efficacy and safety of gemcitabine plus paclitaxel (GT) combination therapy in anthracycline pretreated metastatic first-line setting. Patients and Methods: The study enrolled 26 women with pathologically confirmed and measurable metastatic breast cancer who were previously treated with anthracycline but no prior chemotherapy for metastatic disease. Twenty six and twenty four patients were eligible for toxicity and efficacy evaluations respectively. Mean age was 47.3 years and median ECOG performance status was 0. Twenty patients (76.9 percent) had visceral metastases, most commonly located in liver and lung. Treatment schedule was as follows: paclitaxel 175 mg/m² was administered intravenously in 3 hours on Day 1 and gemcitabine 1000 mg/m² was administered intravenously in 30 minutes on Day 1 after paclitaxel application, and on Day 8 every 21 days. Results: Objective response rate was 41.7 percent (95 percent CI: 21.9-61.4) with 16.7 percent (95 percent CI: 1.7-31.6 percent) CR, and 25.0 percent (95 percent CI: 7.6-42.3 percent) PR. Median time to progression and overall survival were 9.6 and 14.5 months, respectively. Grade 3-4 toxicity was observed in 34.6 percent (9) patients. Treatment of two patients was discontinued due to toxicity, consisting of Grade 3 hypersensitivity reactions and Grade 4 infections in one patient each. Dose reductions due to myelotoxicity were performed in 4 (15.3 percent) patients. Hematologic toxicities were generally manageable with appropriate dose modifications and supportive care. Conclusion: Gemcitabine and paclitaxel combination regimen is effective and has manageable toxicity profile as first line metastatic setting.