This study is to examine which dose of DA-3031(PEG-G-CSF) has similar efficacy and safety compared to daily G-CSF in chemotherapy-induced neutropenia.

Eligible subjects are randomly assigned to receive once-per-cycle DA-3031(PEG-G-CSF) or daily G-CSF(up to 10 days). This study is conducted for 1 cycles of chemotherapy.

Inclusion Criteria:

1. Diagnosis of stage II or III breast cancer
2. Age : ≥18, ≤70
3. TAC regimen as adjuvant therapy
4. ANC≥1,500/mm3, Platelet≥100,000/mm3, ECOG : 0 or 1
5. Creatinine < 1.5 x ULN
6. Total bilirubin/AST/ALT < 1.5 x ULN, ALP < 2.5 x ULN
7. Have given a written, informed consent

Exclusion Criteria:

1. Received any other investigational drugs within 30 days of informed consent date
2. Received systemic antibiotics within 72 hours of chemotherapy into this study or Radiation therapy within 4 weeks of informed consent date
3. Infective symptom before chemotherapy into this study
4. Pregnant or lactating women
5. Prior bone marrow or stem cell transplantation
6. Other malignancy history within 5 years
7. HIV positive
8. Prior exposure to pegfilgrastim or filgrastim or other colony-stimulating factors within 6 weeks of informed consent date
9. Prior chemotherapy