ABSTRACT
This study was designed to determine the efficacy and toxicity of weekly docetaxel in metastatic breast cancer when given alone (for HER2/neu negative disease) or with trastuzumab (for HER2/neu overexpressing disease). Patients with metastatic breast carcinoma received docetaxel given on 2 different schedules (group 1A, 33 mg/m2 weekly [n = 21]; group 1B, 40 mg/m2 weekly for 3 weeks with 1 week off [n = 14]). Patients with HER2/neu overexpressing disease also received trastuzumab 4 mg/kg on day 1, then 2 mg/kg on days 8 and 15 of each 28-day cycle (group 2). Fifty-two patients were treated with docetaxel alone (group 1A/B, n = 35) or in combination with trastuzumab (group 2, n = 17). Prior taxane therapy given every 3 weeks had been used for metastatic disease in 19 of 35 patients (54%) in group 1A/B and in 2 of 17 patients (12%) in group 2. The mean delivered dose intensity of docetaxel was 29 mg/m2 per week. Partial response occurred in 7 of 35 patients (21%; 95% exact binomial confidence interval [CI], 9%-38%) treated with docetaxel alone, including 3 of 19 taxane-pretreated patients (16%) and 4 of 16 taxane-naive patients (25%). Partial response occurred in 10 of 17 patients (59%; 95% CI, 34%-82%) treated with docetaxel/trastuzumab. The most common grade 3/4 toxicities, occurring in more than or equal to 10% of patients, included neutropenia (21%), pulmonary toxicity (12%), and hyperglycemia (10%). The median times to disease progression were 4.5 months (95% CI, 2.5-6.5 months) in the docetaxel group and 8.5 months (95% CI, 4.5-12.5 months) in the docetaxel/trastuzumab group. Weekly docetaxel/trastuzumab is an effective regimen for patients with HER2/neu overexpressing metastatic breast cancer. Weekly docetaxel may be effective in as many as 20% of patients who had progressive disease after treatment with taxanes given every 3 weeks.