SHR-A1811 for HER2-positive Breast Cancer With Suboptimal Neoadjuvant Response

Inclusion Criteria:

* 1.Female patients with newly diagnosed breast cancer aged 18 to 70 years old;
* 2.Early or locally advanced HER2-positive invasive breast cancer;
* 3.Known hormone receptor status;
* 4.ECOG score of 0-1;
* 5.Patients who were determined by the researchers to have poor therapeutic effect after 4 cycles of neoadjuvant therapy;
* 6.Organ function levels must meet the following requirements:
* 7.Women of childbearing age must undergo a serum pregnancy test within 7 days before enrollment, with a negative result, and be willing to use a medically approved highly effective contraceptive method during the study and within 3 months after the last administration of the study drug.
* 8.The subjects voluntarily participate in this study and sign the informed consent form.

Exclusion Criteria:

* 1\. Patients with metastatic or bilateral breast cancer, or inflammatory breast cancer
* 2\. Patients with grade 3 or higher thrombocytopenia during previous treatment, or grade 3 or higher nausea and vomiting despite primary prevention
* 3\. History of other malignant tumors (except cured carcinoma in situ of the cervix, basal cell carcinoma, etc.) and related treatment history
* 4\. Patients who received major non-breast cancer surgery within 4 weeks before enrollment and have not recovered (except biopsy and PICC)
* 5\. Autoimmune diseases (except special cases such as hypothyroidism and stable type 1 diabetes)
* 6\. Interstitial lung disease, non-infectious pneumonia, uncontrolled systemic diseases
* 7\. History of or planned administration of live attenuated vaccines within 28 days
* 8\. HIV infection, active hepatitis (hepatitis B, hepatitis C, etc.), autoimmune hepatitis
* 9\. Severe infection within 4 weeks, CTCAE grade ≥ 2 active infection within 2 weeks (except neoplastic fever), or evidence of active tuberculosis within 1 year
* 10\. History of allogeneic bone marrow or solid organ transplantation
* 11\. Peripheral neuropathy of grade ≥ 2
* 12\. Severe heart diseases
* 13\. Receipt of systemic immunostimulant therapy within 4 weeks
* 14\. Receipt of systemic immunosuppressant therapy within 2 weeks (except local or physiological dose of hormones)
* 15\. Allergy to study drugs/excipients, or history of severe allergic reaction to other monoclonal antibodies
* 16\. Pregnant or lactating women; fertile women with positive pregnancy test or unwilling to take effective contraception throughout the trial
* 17\. History of neurological/psychiatric disorders , or history of substance abuse, alcoholism, or drug addiction
* 18\. Other circumstances deemed unsuitable for enrollment by the researcher