Considering the efficacy of docetaxel (Taxotere, Rhône-Poulenc Rorer, Antony, France) and doxorubicin in advanced breast cancer and their potential noncross-resistance, two pilot studies of docetaxel/doxorubicin (TA)-based combinations were conducted, one being a phase I dose-finding study of TA and the second a phase II study of docetaxel/doxorubicin/cyclophosphamide (TAC). The only significant toxicity, seen in both trials, was neutropenia and its consequences such as febrile neutropenia without significant documented infections. Extrahematologic and particularly docetaxel-specific side effects (fluid retention) were mild. Particularly noteworthy was the absence of significant cardiac toxicity; overall, there was only one case of congestive heart failure (1%). In terms of efficacy, response rates in excess of 70% and 80% were noted in both studies, even for patients with visceral metastases. Several phase III randomized trials using TA or TAC are presently being performed in first-line metastatic breast cancer and most importantly in the adjuvant setting to assess whether TA-based combinations will change the natural history of breast cancer.