A Multicenter, Randomized, Open, Phase III Trial of ddEC-THPvs Evaluating the Efficacy and Safety of TCHP Neoadjuvant Therapy for HER2-positive Breast Cancer

Inclusion Criteria:

1. Age: 18 \~70 years old, female;
2. Histologically confirmed patients with previously untreated stage Ⅱ-Ⅲ HER2-positive breast cancer;
3. HER-2 positive breast cancer, defined as immunohistochemical (IHC) detection of 3+ or in situ hybridization (FISH) results of HER2 gene amplification;
4. There is at least one measurable objective lesion according to RECIST 1.1 criteria;
5. ECOG Physical fitness score is 0-2;
6. Left ventricular ejection fraction LVEF≥50%;
7. Bone marrow function: neutrophils ≥1.5×109/L, platelets ≥100×109/L, hemoglobin ≥90g/L;
8. Liver and kidney function: serum creatinine ≤1.5 times the upper limit of normal value; AST and ALT≤2.5 times the upper limit of normal, or ≤5 times the upper limit of normal in the presence of liver metastasis; Total bilirubin ≤1.5 times the upper limit of normal, or ≤2.5 times the upper limit of normal in patients with Gilbert's syndrome, creatinine clearance greater than 30 mL/min;
9. For female patients who are not menopausal or have not been surgically sterilized: consent to abstinence or use an effective contraceptive method during treatment and for at least 7 months after the last dose in the study treatment
10. The patient has good compliance with the planned treatment, can understand the research process of the study and sign the written informed consent.

Exclusion Criteria:

1. Stage IV (metastatic) breast cancer patients;
2. Patients with inflammatory breast cancer
3. Serious heart disease or discomfort, including but not limited to:

   * History of heart failure or systolic dysfunction (LVEF \< 50%)
   * High-risk uncontrolled arrhythmias such as atrial tachycardia, resting heart rate \> 100 bpm, significant ventricular arrhythmias (e.g., ventricular tachycardia) or higher-grade atrioventricular block (i.e., Mobitz II second-degree atrioventricular block or third-degree atrioventricular block) Angina pectoris that requires antiangina medication
   * valvular heart disease of clinical significance
   * ECG showed transmural myocardial infarction
   * Poor hypertension control (systolic blood pressure \> 180 mmHg and/or diastolic blood pressure \> 100 mmHg)
4. Known allergic history of drug components of this protocol; A history of immunodeficiency, including HIV positive, or other acquired, congenital immunodeficiency diseases, or a history of organ transplantation;
5. Patients with severe systemic infection or accompanied by other serious diseases;
6. Have developed other malignant tumors within the previous 5 years, except for cured cervical carcinoma in situ and non-melanoma skin cancer;
7. Pregnant and lactating women, fertile women who tested positive for baseline pregnancy tests, or patients of childbearing age who were unwilling to take effective contraceptive measures during the entire trial period and within 6 months after the last study;
8. Patients who participated in other studies within 30 days prior to the first dose of the investigational drug;
9. Patients deemed unsuitable for this study by the investigator.
10. The patient has good compliance with the planned treatment, can understand the research process of the study and sign the written informed consent.