Pegfilgrastim is a long-acting recombinant human granulocyte-colony stimulating factor as support for chemotherapy, which can be used conveniently.

According to the package inserts in America, Europe, and China, the recommended dose for pegfilgrastim is 6mg per cycle, while it is recommended at a dose of 3.6mg in Japan. It is still unclear whether pegfilgrastim 3mg can produce similar efficacy with pegfilgrastim 6mg.

In this trial, the investigators prospectively compared the efficacy and safety of pegfilgrastim 3mg with 6mg in patients with breast cancer receiving AC regimen, a commonly used regimen in adjuvant chemotherapy for breast cancer.

All patients received AC regimen (epirubicin or pirarubincin in combination with cyclophosphamide) intravenously. Epirubicin 90mg/m^2 (or pirarubicin 60mg/m^2) and cyclophosphamide 600mg/m^2 were administered on day 1 of the chemotherapy cycle. AC regimen was administered bi-weekly or 3-weekly.

Eligible patients were randomly assigned to 3mg arm (the study arm) and 6mg arm (the control arm) in a 1:1 ratio, stratified according to body weight (≤60kg or >60kg). Patients in the study arm and the control arm received a subcutaneous injection of 3mg PEG-rhG-CSF and 6mg, respectively, forty-eight hours after completing chemotherapy infusion.

Inclusion Criteria:

• female aged 18-69 years
• diagnosed pathologically as early breast cancer
• with indication for adjuvant chemotherapy and suitable for AC regimen (epirubicin and cyclophosphamide, or pirarubicin and cyclophosphamide, planned chemotherapy with taxanes after AC regimen were allowed)
• received no prior chemotherapy (chemotherapy naïve)
• have Karnofsky performance status ≥ 80,
• baseline hemoglobin ≥90g/L, white blood cell count ≥4.0X10^9/L,ANC≥2.0X10^9/L, platelet count ≥100X10^9
• adequate cardiac, hepatic and renal function

Exclusion Criteria:

• enrolled onto or had not yet completed other investigational drug trials
• allergic to any component of PEG-rhG-CSF injection, or other biological products derived from genetically engineering Escherichia coli;
• pregnant or lactating women;
• previous large volume radiotherapy, or prior bone marrow or stem-cell transplantation