Dose response of pegfilgrastim in Japanese breast cancer patients receiving six cycles of docetaxel, doxorubicin, and cyclophosphamide therapy: a randomized controlled trial

PURPOSE: A phase II, open-label, dose-finding, randomized study was performed to evaluate the recommended dose of pegfilgrastim in Japanese breast cancer patients. METHODS: Patients received 1.8, 3.6, or 6.0 mg of pegfilgrastim once per chemotherapy cycle for up to 6 cycles. Patients received docetaxel, doxorubicin, and cyclophosphamide (TAC) therapy followed by pegfilgrastim on the next day. RESULTS: Pegfilgrastim was administered to 87 women with stage II/III invasive breast carcinoma. The duration of grade 4 neutropenia in the first cycle, the primary endpoint, was 2.2 ± 0.9 days, 1.5 ± 0.9 days, and 1.4 ± 0.7 days in the 1.8, 3.6, and 6.0 mg groups, respectively. This finding indicated that pegfilgrastim efficacy peaked at 3.6 mg. Pegfilgrastim doses up to 6.0 mg were considered safe. CONCLUSION: A 3.6-mg pegfilgrastim dose may be safe and effective for Japanese patients. A confirmatory study is required to establish safety and efficacy at this dose for intensive anti-cancer chemotherapy.