Clinical Study on Adjuvant Therapy of TQB3616 Combined With Endocrine Therapy Compared With Placebo Combined With Endocrine Therapy in Patients With Breast Cancer

Inclusion Criteria:

• The subjects voluntarily joined the study and signed the informed consent, with goodcompliance.

• Age: 18-75 years old (upon signing the informed consent); Eastern CooperativeOncology Group Performance Status (PS) score: 0~1;

• Surgical treatment of radical mastectomy;

• Pathological examination confirmed HR positive and HER2 negative invasive breastcancer;

• The major organs are functioning well, meeting the following criteria：

1. Blood biochemical tests should meet the following criteria (no correctivetherapy has been used within 7 days prior to screening)：

2. Hemoglobin (HB) ≥90 g/L；

3. Neutrophil absolute value (NEUT) ≥ 1.5×109/L；

4. Platelet count (PLT) ≥ 100 ×109/L；

5. Blood biochemical tests should meet the following criteria (no correctivetherapy has been used within 7 days prior to screening)：

6. Total bilirubin (TBIL) ≤ 1.5 times the upper limit of normal (ULN)；

7. Alanine transferase (ALT) and aspartate transferase (AST) ≤ 1.5×ULN；

8. Serum creatinine (Cr) ≤ 1.5×ULN, or creatinine clearance (Ccr) ≥ 60ml/min；

9. Blood clotting tests must meet the following criteria (no anticoagulanttherapy)：

10. Prothrombin time (PT) ≤ 1.5×ULN;

11. Activated partial thromboplastin time (APTT) ≤ 1.5×ULN;

12. International Normalized ratio (INR) ≤ 1.5×ULN.

13. Left ventricular ejection fraction (LVEF) ≥50%.

Exclusion Criteria:

• Complicated diseases and medical history:

1. Has had other malignant tumors within 5 years or currently has other malignanttumors;

2. Have a variety of factors that affect oral medication (such as inability toswallow);

3. Current history of serious lung disease such as interstitial pneumonia；

4. Severe infections common terminology criteria for adverse events (≥CTCAE (common terminology criteria for adverse events) 2 grade) that were active oruncontrolled before the study treatment started (Except hair loss andhemoglobin)；

• Known allergy to aromatase inhibitors, tamoxifen, TQB3616/ placebo, or anyexcipients;

• There was a history of live attenuated vaccine vaccination within 28 days prior torandomization or live attenuated vaccine vaccination was planned during the studyperiod;

• Participated in clinical trials of other antitumor agents within 4 weeks prior torandomization；

• The presence of other serious physical or mental illnesses or abnormalities inlaboratory tests that may increase the risk of study participation or interfere withthe study results, as well as subjects who are deemed unsuitable for studyparticipation for other reasons by the investigator.