Weekly Gemcitabine and Trastuzumab in the Treatment of Patients With HER2-Overexpressing Metastatic Breast Cancer

BackgroundThe use of trastuzumab in combination with either a taxane or vinorelbine has improved the efficacy of treatment for women with HER2-positive (HER+) breast cancer. We investigated the activity and toxicity of the gemcitabine/trastuzumab combination as first- or second-line treatment in women with HER2+ metastatic breast cancer (MBC).Patients and MethodsForty-one women with HER2+ MBC were treated with gemcitabine 1000 mg/m2 intravenously (I.V.) days 1, 8, and 15 and trastuzumab 4-mg/kg I.V. loading dose and then 2 mg/kg weekly. Cycles were repeated every 28 days. Patients were evaluated after 8 weeks of treatment; responders/stable patients continued treatment until progression.ResultsPatients received a median of 28 weeks of treatment. Eleven of 37 evaluable patients (30%; 95% CI, 17%–46%) had major responses. The median progression-free survival (PFS) was 4 months (95% CI, 1.9–5.3 months), with a 1-year PFS of 17%. Four of 15 patients (27%) who had previously received trastuzumab for MBC had partial responses. The gemcitabine/trastuzumab combination was well tolerated.ConclusionThe combination of gemcitabine and trastuzumab is an active regimen but appears less active than trastuzumab in combination with either taxanes or vinorelbine. The role of gemcitabine/trastuzumab (versus gemcitabine alone) in women who have already received a trastuzumab-containing regimen for HER2+ MBC is not defined by this study.