Purpose: This phase II study was undertaken to define the efficacy and toxicity of pemetrexed in combination with gemcitabine in patients with metastatic breast cancer.
Patients and methods: Patients with measurable metastatic breast cancer who had previously received an anthracycline and a taxane in either the adjuvant or metastatic setting were treated with gemcitabine 1250 mg/m2 (intravenous; days 1 and 8) and pemetrexed 500 mg/m2 (intravenous; day 8) every 21 days.
Results: Fifty-nine patients received a median of five cycles (range one to 22) of treatment and were followed until death or for a median of 28 months (range 19.4-36.6) among living patients. Fourteen partial responses for an overall response rate of 24% [95% confidence interval (CI) 16% to 39%] were documented. Nine (15%; CI 5% to 32%) patients had stable disease for >6 months. The median survival time was 10.3 months (95% CI 8.3-18.9) and the 1 year survival rate was 49% (95% CI 38% to 64%). The median time to progression was estimated to be 3.7 months (95% CI 2.3-5.3). The most common grade 3 or 4 toxicities were neutropenia and thrombocytopenia in 83% and 27% of patients, respectively. Fourteen percent of patients experienced febrile neutropenia. Other common grade 3 or 4 non-hematological toxicities included fatigue (17%), dyspnea (15%), rash (7%) and anorexia (5%).
Conclusions: The combination of pemetrexed and gemcitabine is clinically active, with an overall response rate of 24% in patients with metastatic breast cancer who have previously been treated with an anthracycline and a taxane. Myelosuppression (66% grade 4 neutropenia and 14% febrile neutropenia) was the major treatment-related toxicity observed for this combination.