Phase II Study of Gemcitabine Monotherapy as a Salvage Treatment for Japanese Metastatic Breast Cancer Patients after Anthracycline and Taxane Treatment

This Phase II study was conducted to evaluate efficacy and safety of gemcitabine monotherapy in anthracycline and taxane pre-treated Japanese metastatic breast cancer patients. At Step 1, twelve patients were divided into two groups of six patients each and the dose-limiting toxicity was evaluated at gemcitabine 1000 and 1250 mg/m(2) to determine the dose for Step 2. At Step 2, an additional 56 patients were assessed for efficacy and safety of gemcitabine monotherapy. Patients were treated with gemcitabine on days 1 and 8 of a 21-day cycle and explored incidence of adverse events graded by Common Terminology Criteria for Adverse Events (CTCAE) version 3.0, overall response rate (RR), time to progression disease and overall survival time. Gemcitabine 1250 mg/m(2) was determined as the dose for Step 2. Adverse events reported in this study were similar in type, frequency and toxicity grades as seen in other tumor types. Of the 62 patients at 1250 mg/m(2), 1 complete response (1.6%), 4 partial response (6.5%) and 20 stable disease (32.3%) were achieved, yielding an RR of 8.1% (95% CI: 2.7%, 17.8%). Median time to progression was 92.0 days (range: 29-651 days). The median survival time was 17.8 months (95% CI: 14.9 months to incalculable). Gemcitabine at 1250 mg/m(2) on days 1 and 8 of a 21-day cycle was tolerable and can be a salvage treatment option for Japanese metastatic breast cancer patients previously treated with anthracyclines and taxanes.