Study to Compare the Efficacy and Safety of F-627 and GRAN®

Inclusion Criteria:

1. Willing to sign the informed consent form and able to comply with protocol requirements;
2. 18-75 years old;
3. Female postoperative patients with breast cancer who require adjuvant chemotherapy, and are planned to receive at least 4 cycles of EC chemotherapy, namely epirubicin 100 mg/m\^2 + cyclophosphamide 600 mg/m\^2;
4. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2;
5. Absolute neutrophil count (ANC) ≥ 2.0 × 10\^9/L, hemoglobin (Hb) ≥ 11.0 g/dL, and platelet (PLT) ≥ 100 × 10\^9/L prior to enrollment;
6. Hepatic and renal functions: Total bilirubin ≤ 1.5 × upper limit of normal (ULN), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 × ULN, serum creatinine ≤ 1.5 × ULN;
7. Left ventricular ejection fraction \> 50%;
8. Women without child-bearing potential, i.e., women who have had menopause for at least 1 year or who have undergone sterilization (bilateral tubal ligation, double oophorectomy or hysterectomy); patients with child-bearing potential should agree to take appropriate contraceptive measures, including condoms, spermicidal condoms, foams, gels, contraceptive barrier, intrauterine devices (IUD), and contraceptives (oral or injection), starting from 1 month before the start of the study until 30 days after the end of the study.

Exclusion Criteria:

1. Radiation therapy within 4 weeks prior to enrollment;
2. Patients with breast cancer who have received neoadjuvant chemotherapy before surgery;
3. Prior bone marrow or stem cell transplant;
4. With other malignant tumors other than breast cancer;
5. Patients who have received a treatment with recombinant human granulocyte colony stimulating factor within 6 weeks prior to randomization;
6. Diagnosed with acute congestive heart failure, cardiomyopathy, or myocardial infarction by clinical diagnosis, ECG or other approaches;
7. With any disease that may cause splenomegaly;
8. With acute infection, chronic active Hepatitis B within 1 year (unless patients tested negative for HBsAg prior to enrollment), or Hepatitis C;
9. Women in pregnancy or breastfeeding;
10. Known HIV positive or AIDS;
11. With active tuberculosis (TB); history of TB exposure, unless negative for tuberculin test; TB patients undergoing treatment; or suspected TB evaluated by chest x-ray;
12. With sickle cell anemia;
13. With alcohol or drug abuse that may affect the compliance with the study;
14. With known hypersensitivity to granulocyte colony stimulating factor or excipients;
15. Have received any other investigational drug within 1 month or 5 half-lives of the investigational drugs prior to enrollment (whichever is longer);
16. Patients with diseases or symptoms unsuitable for participating in the trial. For example, the study drugs may compromise the health of the patient or the assessment of adverse events may be affected.