Paclitaxel combination therapy in the treatment of metastatic breast cancer.

After the single-agent activity of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) was confirmed, trials to develop a synergistic combination began. Doxorubicin, the most active agent for breast cancer, was studied first. As paclitaxel became more available, other combinations, including high-dose regimens and adjuvant therapies, have been studied. No optimal combination regimen has been defined. Recent and/or ongoing trials are looking at paclitaxel in combination with cisplatin, cyclophosphamide, 5-fluorouracil/ folinic acid, and mitoxantrone combinations, as well as with high-dose regimens and as adjuvant therapy. This review describes a plethora of combination studies finally under way to better define the optimal use of paclitaxel in breast cancer therapies, both as adjuvant treatment and for metastatic disease. Because of the unpredictable nature of drug interactions related to schedule and sequence, ad hoc combinations should not be undertaken outside the context of a well-designed trial.