Gemcitabine, paclitaxel, and trastuzumab in metastatic breast cancer.

A phase II trial evaluated the effectiveness and toxicity of combination paclitaxel (Taxol), gemcitabine (Gemzar), and trastuzumab (Herceptin) as first-line therapy for patients with newly diagnosed HER2-overexpressing metastatic breast cancer. To date, 27 patients have received paclitaxel at 175 mg/m2 over 3 hours on day 1, plus gemcitabine at 1,200 mg/m2 on days 1 and 8, plus trastuzumab at a 4-mg/kg loading dose on day 1, followed by 2 mg/kg weekly. Treatment cycles were repeated every 21 days. Responding or stable patients who had received six cycles of combination therapy continued single-agent trastuzumab weekly until disease progression. Treatment was generally well tolerated with grade 4 toxicity limited to myelosuppression. In all, 12 patients have achieved a partial remission and 1 patient had progressive disease; 14 patients continue treatment and have not yet been evaluated for response. Combination treatment with paclitaxel, gemcitabine, and trastuzumab is well tolerated and appears to be highly active. Accrual will continue to a total enrollment of 46 patients.