Purpose: Several groups have reported that the combination of doxorubicin plus paclitaxel given as a 3-hour intravenous (IV) infusion for up to eight cycles produces a high response rate (> 80%) and complete response rate (> 20%) in metastatic breast cancer, but is also complicated by a 20% incidence of congestive heart failure (CHF). The purpose of this phase II trial was to evaluate the antineoplastic activity of the regimen in a multi-institutional setting and to reduce the incidence of cardiotoxicity by limiting treatment to a maximum of six cycles.
Patients and methods: Fifty-two patients with advanced breast cancer received doxorubicin (60 mg/m(2) by IV injection) followed 15 minutes later by paclitaxel (200 mg/m(2) by IV infusion over 3 hours) every 3 weeks for four to six cycles.
Results: Objective responses occurred in 25 of 48 assessable patients (52%; 95% confidence interval [CI], 38% to 66%), including four complete responses (8%; 95% CI, 0% to 16%). The median cumulative doxorubicin dose given was 240 mg/m(2) (range, 132 to 360 mg/m(2)). Eleven patients (21%) were documented as having a decrease in the LVEF below normal, including three patients (6%; 95% CI, 0% to 12%) who developed CHF.
Conclusion: The doxorubicin/paclitaxel regimen that we used is unlikely to produce an objective response rate of more than 70% and a complete response rate of more than 20% in patients with metastatic breast cancer, and proved to be excessively cardiotoxic for use in the adjuvant setting.