A Study of SHR-A1811 as Neoadjuvant Treatment for Patients With HR-Positive, Low HER2 Expression Breast Cancer

Inclusion Criteria:

1. Patients aged 18 to 70 years old (inclusive);

2. Treatment-naive patients with clinically confirmed T2-T3, any nodal status and M0;

3. HR-positive, HER2 low expression, the expression of Ki-67 exceed 14% invasive breastcancer confirmed by histology or cytology;

4. ECOG performance status of 0-1;

5. Normal organ and bone marrow function;

6. Patients of childbearing age must consent to use highly effective contraception for 7 months from the start of study screening until the last study medication and agreenot to breastfeeding;

7. Patients voluntarily joined the study and signed informed consent;

Exclusion Criteria:

1. Patients have evidence of metastatic breast cancer, or inflammatory breast cancer;

2. Patients previously received antineoplastic therapy or radiotherapy for anymalignancy, excluding cured malignancies such as cervical carcinoma in situ, basalcell carcinoma, or squamous carcinoma;

3. Patients received any other anti-tumor therapy at the same time, including endocrinetherapy, bisphosphonates or immunotherapy;

4. Patients have major surgical procedures unrelated to breast cancer within 4 weeksbefore the first medication, or not fully recovered from surgical procedures;

5. Clinically significant pulmonary or cardiovascular disease;

6. Failure to swallow, chronic diarrhea, intestinal obstruction, or presence of otherfactors affecting drug administration and absorption;

7. Known to be allergic to any study drug or any of its excipients;

8. History of immunodeficiency, including HIV-positive, or other acquired or congenitalimmunodeficiency diseases, or history of organ transplantation;

9. Pregnant and lactating women;

10. Patients with serious concomitant diseases or other comorbidities that willinterfere with the planned treatment, or any other condition that is not suitablefor participation assessed by investigator.