Clinical Research Directory

Inclusion Criteria: Participants must meet all of the following inclusion criteria to be enrolled in this study： 1. The participant voluntarily joins this study, signs the informed consent form, and has good compliance. 2. Female, aged 18-75 years (at the time of signing the informed consent form), meeting one of the following criteria: 1. Has undergone bilateral oophorectomy, or is aged ≥60 years; 2. Aged \<60 years, with continuous amenorrhea for 12 months without pathological or physiological cause, and postmenopausal levels of estradiol (E2) and follicle-stimulating hormone (FSH); 3. Premenopausal or perimenopausal female, willing to receive luteinizing hormone-releasing hormone (LHRH) agonist therapy during the study. 3. ECOG performance status score: 0-1. 4. Life expectancy \>6 months. 5. Histologically or cytologically confirmed HER2-positive invasive breast carcinoma, with HER2 testing meeting the following requirements: 1. HER2 positivity confirmed or verified by the pathology department of the participating center: according to the 2018 ASCO/CAP HER2 testing guidelines, HER2 positivity is defined as immunohistochemistry (IHC) 3+ or in situ hybridization (ISH) positive; 2. For multicentric tumors (multiple tumors involving more than one breast quadrant), one lesion must be sampled from each involved quadrant, and all must be confirmed or verified as HER2 positive by the pathology department of the participating center. 6. HR-positive: ER-positive and/or PR-positive (according to the 2020 ASCO/CAP guidelines, HR positivity includes ER-positive and/or PR-positive, defined as positive staining in ≥1% of tumor cells). 7. Clinical stage at presentation: T2-4, any N, M0 OR any T, N1-3, M0 (per AJCC 8th edition breast cancer staging system). 8. The participant agrees to undergo breast cancer resection surgery when surgical criteria are met after neoadjuvant therapy. 9. Adequate major organ function, meeting the following criteria: 1. Hemoglobin (HGB) ≥90 g/L (without blood transfusion or use of hematopoietic stimulating factors within 7 days prior to examination); 2. Absolute neutrophil count (NEUT) ≥1.5 × 10⁹/L (without blood transfusion or use of hematopoietic stimulating factors within 7 days prior to examination); 3. Platelet count (PLT) ≥100 × 10⁹/L (without blood transfusion or use of hematopoietic stimulating factors within 7 days prior to examination); 4. Total bilirubin (TBIL) ≤1.5 × upper limit of normal (ULN); 5. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤1.5 × ULN; 6. Serum creatinine (CR) ≤1.5 × ULN or creatinine clearance (CCr) ≥60 mL/min (calculated using the standard Cockcroft-Gault formula); 7. Serum albumin ≥30 g/L; 8. Prothrombin time (PT) ≤1.5 × ULN (not receiving anticoagulant therapy); 9. Activated partial thromboplastin time (APTT) ≤1.5 × ULN (not receiving anticoagulant therapy); 10. International normalized ratio (INR) ≤1.5 × ULN (not receiving anticoagulant therapy); 11. Left ventricular ejection fraction (LVEF) ≥50% assessed by echocardiography; 12. QTc interval ≤480 ms on 12-lead electrocardiogram. 10. Female participants of childbearing potential must agree to use contraceptive measures (e.g., intrauterine device, contraceptive pills, or condoms) during the study and for 6 months after study completion; serum pregnancy test must be negative within 7 days prior to study enrollment, and participants must not be breastfeeding. Male participants must agree to use contraceptive measures during the study and for 6 months after study completion. Exclusion Criteria: Participants meeting any of the following criteria will not be enrolled in this study: 1. Female who has received any form of prior antitumor therapy (chemotherapy, radiotherapy, molecular targeted therapy, or endocrine therapy). 2. Currently receiving other antitumor drug therapy. 3. Has bilateral invasive breast cancer, inflammatory breast cancer, or occult breast cancer. 4. Clinical stage IV breast cancer. 5. Breast cancer not confirmed by histopathology. 6. Has had other malignancies within the past 5 years (excluding cured carcinoma in situ of the cervix). 7. Has severe organ dysfunction involving the heart, liver, kidney, or other major organs. 8. Has conditions that may affect drug administration and absorption, such as dysphagia, chronic diarrhea, intestinal obstruction, etc. 9. Has participated in another clinical drug trial within the past 4 weeks. 10. Has a known history of allergy to any component of the study drugs; has a history of immunodeficiency, including positive test for human immunodeficiency virus (HIV), positive test for hepatitis C virus (HCV), active hepatitis B, or other acquired or congenital immunodeficiency diseases, or has undergone organ transplantation. 11. Has a history of any cardiac disease, including arrhythmia requiring medical treatment or clinically significant, myocardial infarction, heart failure, or any other cardiac condition deemed by the investigator to be inappropriate for participation in this study. 12. Is pregnant or breastfeeding; is a woman of childbearing potential with a positive baseline pregnancy test; or is a woman of childbearing potential who is unwilling to take effective contraceptive measures during the entire study period. 13. Has concomitant diseases (including but not limited to severe hypertension, severe diabetes, active infections, etc., not controlled by medication) that, in the investigator's judgment, may pose potential harm to the participant's health or affect study completion. 14. Has a definite history of neurological or psychiatric disorders, including epilepsy or dementia. 15. Is considered by the investigator to be unsuitable for participation in this study for any other reason.