The efficacy and safety of gemcitabine plus paclitaxel combination first-line therapy for Japanese patients with metastatic breast cancer including triple-negative phenotype

Purpose Gemcitabine (GEM)-paclitaxel combination therapy has been confirmed as a standard therapy for metastatic/recurrent breast cancer (MBC) in Western countries. This study was conducted to assess the efficacy and safety of GEM-paclitaxel combination therapy in Japanese MBC patients. Methods Patients were administered paclitaxel 175 mg/m(2) on day 1, and GEM 1,000 or 1,250 mg/m(2) on days 1 and 8 of 21-day cycle. The primary endpoint of this study was overall response rate; secondary endpoints were duration of response, time to progression, survival time and rate. Results Paclitaxel 175 mg/m(2) plus GEM 1,250 mg/m(2) was determined as the recommended dose. A total of 56 patients received 506 cycles of treatment (median: 7.5 cycles) with a relative dose intensity of 79.6% for GEM and 85.8% for paclitaxel. The response rate was 44.6% (25/56 patients), median time to progression 8.6 months and median survival time 27.1 months. In triple-negative patients, the response rate was 35.7% (5/14 patients), and the median time to progression was 6.0 months. The most frequent grade a parts per thousand yen 3 toxicities were neutropenia (82.1%), leukopenia (62.5%) and ALT increase (14.3%). Conclusions This study confirmed the efficacy and safety of GEM-paclitaxel combination therapy in Japanese MBC patients.