To evaluate the safety, tolerability and efficacy of SHR-A1811 in combination with pyrotinib or pertuzumab or adebrelimab or albumin-bound paclitaxel in patients with breast cancer.

Inclusion Criteria:

1. Women aged 18 to 75 (inclusive)
2. Breast cancer confirmed by histology or cytology.
3. ECOG score is 0 or 1
4. An expected survival of ≥ 12 weeks
5. At least one measurable lesion according to RECIST v1.1 criteria
6. Have adequate renal and hepatic function
7. Patients voluntarily joined the study and signed informed consent

Exclusion Criteria:

1. Have other malignancies within the past 5 years
2. Active central nervous system metastasis without surgery or radiotherapy
3. Presence with uncontrollable third space effusion
4. Have undergone other anti-tumor treatment within 4 weeks before the first dose
5. Immunosuppressant or systemic hormone therapy was used within 2 weeks prior to the first dose
6. Any active autoimmune disease or a history of autoimmune disease
7. A history of immune deficiency
8. Clinically significant cardiovascular disorders
9. Clinically significant history of lung disease
10. The toxicity from previous anti-tumor treatment has not recovered to ≤ grade I
11. Known hereditary or acquired bleeding tendency
12. Active hepatitis and liver cirrhosis
13. Presence of other serious physical or mental diseases or laboratory abnormalities