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.