A review of the efficacy and safety of docetaxel as monotherapy in metastatic breast cancer.

To date, although statistically significant, the overall impact of adjuvant chemotherapy on the survival of women with nonmetastatic breast cancer has been disappointing. Hence, new agents that have shown good activity against metastatic disease should be assessed quickly in the adjuvant setting. Docetaxel (Taxotere; Rhône-Poulenc Rorer, Antony, France) is one of the most promising drugs that has emerged in recent years, with phase II studies in previously untreated metastatic breast cancer indicating a high overall response rate of approximately 60%. A recent large, randomized comparison demonstrated docetaxel to be superior to doxorubicin with regard to response rate, and it is the only agent to have shown this superiority. Docetaxel was also tolerated better. A second randomized trial in patients who had already failed an anthracycline-containing regimen showed that docetaxel-treated patients survived significantly longer than those treated with the combination of mitomycin C and vinblastine. The apparent superiority of docetaxel over doxorubicin and the lack of complete cross-resistance between these drugs, which has been demonstrated in trials involving anthracycline-resistant patients, suggest a possible future role for docetaxel, either alone or in combination with the anthracycline, in earlier stages of metastatic breast cancer and indeed in the adjuvant treatment of early stage disease. The combination of docetaxel with doxorubicin appears particularly promising in this regard and, unlike the doxorubicin/paclitaxel doublet, has not been reported to produce clinically significant cardiomyopathy. The high activity of docetaxel provides a compelling rationale for its study as a component of adjuvant therapies. Investigators in Brussels and Dublin have recently demonstrated the feasibility of two candidate adjuvant programs. Large phase II adjuvant trials involving docetaxel are now being assessed.