SHR-A1811 Plus Pertuzumab in the Neoadjuvant Treatment of HER2 Positive BC

Inclusion Criteria:

* Age: 18-70 years old, ECOG 0-1 point.
* Clinical T2-T4, with any LN, M0.
* HER2+, invasive breast cancer confirmed by histopathology;(HER2 positive expression means that there is at least one case of tumor cell immunohistochemical staining intensity of 3+or positive confirmed by fluorescence in situ hybridization \[FISH\] in the pathological test/review of the primary focus conducted by the Pathology Department of the Research Center Hospital).
* Having clinically measurable lesions: measurable lesions displayed on ultrasound, mammography, or MR (optional) within the first month of randomization.
* Organ and bone marrow function tests within one month before chemotherapy indicate no contraindications to chemotherapy：Absolute value of neutrophil count ≥ 1.5 × 10\^9/L; Hemoglobin ≥ 90g/L; Platelet count ≥ 100 × 10\^9/L; Total bilirubin≤1.5 ULN (upper limit of normal value); Creatinine≤1.5 × ULN; AST/ALT ≤ 2.5 × ULN.
* Cardiac ultrasound: Left ventricular ejection fraction (LVEF ≥ 50%).
* Women of childbearing age tested negative for serum pregnancy test 7 days before randomization.
* Sign an informed consent form.

Exclusion Criteria:

* Stage IV (metastatic) breast cancer.
* Has received chemotherapy, endocrine therapy, targeted therapy, reflex therapy, etc. for this disease.
* The patient has a second primary malignant tumor, except for fully treated skin cancer.
* The patient had undergone major surgical procedures unrelated to breast cancer within 4 weeks before enrollment, or the patient has not fully recovered from such surgical procedures.
* The presence of uncontrolled cardiovascular and cerebrovascular disease, including (but not limited to) any of the following within the 6 months prior to the first dose: congestive heart failure (NYHA III or IV), myocardial infarction or cerebral infarction, pulmonary embolism, unstable angina, or arrhythmia requiring treatment at the time of screening; Primary cardiomyopathy (e.g., dilated cardiomyopathy, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, restricted cardiomyopathy, undefined cardiomyopathy); A clinically significant history of prolonged QTc, grade II type II atrioventricular block or grade III atrioventricular block or QTc interphase (F method) \> 470 msec (female); Atrial fibrillation (EHRA grade ≥2b); Unmanageable hypertension, which the investigators judged unsuitable for study participation.
* Due to serious and uncontrollable other medical diseases, researchers believe that there are contraindications to chemotherapy.
* Individuals with a known history of allergies to the drug components of this protocol;
* Having a history of immunodeficiency, including HIV testing positive, or suffering from other acquired or congenital immunodeficiency diseases, or having a history of organ transplantation.