Neutropenia is one of the most frequent adverse effects of chemotherapy, and the main factor to limit the dosage and the continuation of chemotherapy. A newly pegylated rhG-CSF was independently developed by JIANGSU HENGRUI Medicine Co., Ltd, China. Phase 1a, 1b trials have shown that pegylated rhG-CSF has decreased renal clearance, increased plasma half-life, and prolonged efficacy in compare with rhG-CSF. The purpose of this study is to determine the safety and effectiveness of pegylated rhG-CSF in preventing neutropenia following chemotherapy in patients with breast cancer.

Inclusion Criteria:

• Pathology diagnosis of breast cancer,Chemotherapy naïve
• ECOG performance status 0-1
• Age 18 to 70 years
• Available for at least 2 cycles of consistent neoadjuvant/adjuvant therapy
• White blood cell ≥ 4.0×109/L; absolute neutrophil count ≥2.0 × 109/L; platelet count ≥ 100 × 109/L
• Alanine aminotransferase ≤1.5×ULN; aspartate aminotransferase ≤1.5×ULN; serum creatinine ≤1.5×ULN
• No obvious cardiac dysfunction

Exclusion Criteria:

• Prior bone marrow or stem cell transplantation
• Received systemic antibiotics treatment within 72 h of chemotherapy
• Other disease might have influence on bone marrow function
• Radiation therapy within 4 weeks of randomization into this study
• Previous exposure or or allergic to Pegylated rhG-CSF
• Pregnancy, lactation