Phase II trial of docetaxel in advanced anthracycline-resistant or anthracenedione-resistant breast cancer.

PURPOSE: The purpose of this study was to evaluate the clinical efficacy and safety of docetaxel in patients with metastatic breast cancer (MBC) resistant to doxorubicin or mitoxantrone. PATIENTS AND METHODS: Docetaxel 100 mg/m2 was administered as a 1-hour intravenous (IV) infusion every 3 weeks to 42 patients registered at four centers. Patients must have received at least one but no more than two prior chemotherapy regimens for MBC (in addition to any prior adjuvant therapy). One of the regimens for metastatic breast cancer must have included an anthracycline or anthracenedione and the cancer must have progressed on that regimen. RESULTS: Objective responses were seen in 20 of 35 assessable patients (three complete responses CRs and 17 partial responses PRs), for an objective response rate of 57% (95% confidence interval CI, 39% to 74%) and in 21 of 42 registered patients (50% response rate RR; 95% CI, 34% to 66%) entered onto the trial. The median response duration was 28 weeks. The most common toxicity in this study was grade 4 neutropenia, which occurred in 95% of patients. Other clinically significant nonhematologic side effects included stomatitis, skin reactions, neurosensory changes, asthenia, and fluid retention. Patients who received dexamethasone premedication had a later onset of fluid retention than those who did not receive dexamethasone (onset at a median cumulative docetaxel dose of 503 mg/m2 and 291 mg/m2, respectively). CONCLUSION: Docetaxel at this dose and schedule has a high level of antitumor activity in patients with treatment-refractory advanced breast cancer, and appears to be one of the most active agents for the treatment of this patient population.