Single-agent docetaxel (Taxotere) in randomized phase III trials

Until recently, there has been no standard treatment for patients with metastatic breast cancer who have failed an anthracycline-containing regimen, and no definitive phase III trials had been conducted in this setting. The results of three randomized phase III clinical trials of single-agent docetaxel (Taxotere, Rhône-Poulenc Rorer, Collegeville, PA) 100 mg/m2 every 3 weeks in comparison to combination chemotherapy regimens in patients with metastatic breast cancer pretreated with an anthracycline-based chemotherapy regimen are reviewed and reported. An overall response rate of between 30% and 42% was reported for single-agent docetaxel, which was higher in comparison to response rates attained with the combination chemotherapy regimens in all three trials. Noteworthy were findings of a significantly improved overall survival for docetaxel-treated patients in one of the comparative trials. These results firmly establish docetaxel as preferred therapy over combination chemotherapy regimens with mitomycin C plus vinblastine, methotrexate plus 5-fluorouracil, or 5-fluorouracil plus vinorelbine in the therapy of anthracycline-resistant and/or anthracycline-pretreated metastatic breast cancer patients. The results document the continued high level of docetaxel antitumor activity in previously anthracycline-exposed patients initially reported in phase II trials and confirm a substantial lack of anthracycline cross-resistance. The higher response rate of single-agent docetaxel versus single-agent doxorubicin as demonstrated in a fourth randomized phase III trial gives credence to the presumption that the combination of these two agents may provide a highly effective chemotherapy regimen in the management of breast cancer patients.