Abstract

Purpose: This randomized, multicenter, phase III study compared doxorubicin and docetaxel (AT) with doxorubicin and cyclophosphamide (AC) as first-line chemotherapy (CT) in metastatic breast cancer (MBC). Patients and Methods: Patients (n = 429) were randomly assigned to receive doxorubicin 50 mg/m 2 plus docetaxel 75 mg/m 2 (n = 214) or doxorubicin 60 mg/m 2 plus cyclophosphamide 600 mg/m 2 (n = 215) on day 1, every 3 weeks for up to eight cycles. Results: Time to progression (TTP; primary end point) and time to treatment failure (TTF) were significantly longer with AT than AC (median TTP, 37.3 v 31.9 weeks; log-rank P = .014; median TTF, 25.6 v 23.7 weeks; log-rank P = .048). The overall response rate (ORR) was significantly greater for patients taking AT (59%, with 10% complete response [CR], 49% partial response [PR]) than for those taking AC (47%, with 7% CR, 39% PR) (P = .009). The ORR was also higher with AT in patients with visceral involvement (58% v 41%; liver, 62% v 42%; lung, 58% v 35%), three or more organs involved (59% v 40%), or prior adjuvant CT (53% v 41%). Overall survival (OS) was comparable in both arms. Grade 3/4 neutropenia was frequent in both groups, although febrile neutropenia and infections were more frequent for patients taking AT (respectively, 33% v 10%, P < .001; 8% v 2%, P = .01). Severe nonhematologic toxicity was infrequent in both groups, including grade 3/4 cardiac events (AT, 3%; AC, 4%). Conclusion: AT significantly improves TTP and ORR compared with AC in patients with MBC, but there is no difference in OS. AT represents a valid option for the treatment of MBC.