A randomized phase II study of alternating and sequential regimens of docetaxel and doxorubicin as first-line chemotherapy for metastatic breast cancer

Background: This phase II study evaluated the feasibility and efficacy of alternating and sequential regimens of docetaxel and doxorubicin as first-line chemotherapy for metastatic breast cancer (MBC). Patients and methods: Women with MBC requiring first-line chemotherapy for progressive disease (n = 106) were randomized and received 3-weekly monotherapy with docetaxel (T, 100 mg/m(2), 1-h i.v. infusion) and doxorubicin (A, 75 mg/m(2), 20-30-min i.v. infusion) either on a cycle-by-cycle alternating basis (ATATATAT, n = 51) or sequentially each for four cycles (TTTTAAAA, n = 55). Results: For both regimens, the median number of cycles administered was the maximum of eight. The alternating and sequential groups achieved similar objective tumor response rates (60% and 67%, respectively) and similar median duration of response (47 and 44 weeks, respectively). With a median follow-up of 31 months, median survival times were estimated at 20 and 26 months in the alternating and sequential groups, respectively. No unexpected toxicities were reported. Compared with alternating therapy, patients receiving sequential therapy were more likely to complete the planned eight chemotherapy cycles (69% versus 63%), and had a lower incidence of febrile neutropenia (2% versus 14%). Conclusions: Alternating and sequential docetaxel-doxorubicin regimens are viable alternatives to simultaneous combination therapy in MBC, with sequential therapy achieving slightly higher response rates and improved tolerability compared with alternating therapy.