Phase II Study of Concurrent Administration of Doxorubicin and Docetaxel as First-Line Chemotherapy for Metastatic Breast Cancer

Objective: To evaluate the efficacy and toxicity of concurrent administration of doxorubicin and docetaxel, without prophylactic use of granulocyte colony-stimulating factor, as first-line chemotherapy in patients with metastatic breast cancer (MBC). Methods: This multi-institutional study enrolled 40 women; 37 were assessable for efficacy and all 40 patients were evaluated for toxicity. Treatment consisted of 50 mg/m2 doxorubicin and 60 mg/m2 docetaxel on day 1 every 3–4 weeks. Results: Patients received a total of 251 cycles of chemotherapy (median, 5 cycles; range, 1–13 cycles). Of the 37 patients assessable for efficacy, 2 had a complete response and 24 had partial responses, which accounted for a 70% objective response rate (95% confidence interval, 53–84%). The median time to treatment failure was 30.1 weeks (range, 3.3–80.7 weeks). Grade 4 neutropenia was observed in 88% of patients and was the most frequent haematological toxicity. Febrile neutropenia was seen in 40% of patients, but no severe infections were observed. Non-haematological toxicity was generally tolerable. There were 2 grade 4 adverse events, which included 1 bleeding duodenal ulcer and 1 hypersensitivity reaction, but grade 3 episodes were infrequent. None of the patients developed congestive heart failure or asymptomatic decrease of left ventricular ejection fraction to less than 50%. Fluid retention syndrome ≤ grade 2 was observed in 25% of patients at a median cumulative dose of docetaxel of 270 mg/m2. Conclusion: Concurrent administration of 50 mg/m2 doxorubicin and 60 mg/m2 docetaxel is active with a manageable toxicity profile as first-line chemotherapy for MBC.