Clinical Research Directory

Inclusion Criteria: * Subjects voluntarily enrolled in this study with good compliance * Age: 18-75 years old; Eastern Cooperative Oncology Group Performance Status (ECOG PS) score: 0-1 * HER2 positive, recurrent or metastatic invasive breast cancer confirmed by histopathology or cell pathology * Defined hormone receptor (HR) status * Has not received systemic anti-tumor therapy during the recurrence/metastasis stage (acceptable ≤ first-line endocrine therapy) * If receiving (new) adjuvant therapy, it is required that the time interval between the end of systemic therapy (excluding endocrine therapy) and the discovery of recurrence/metastasis be greater than 12 months * Have at least one measurable lesion according to RECIST 1.1 criteria; * Good major organ function Exclusion Criteria: * It is known that there is spinal cord compression or active central nervous system metastasis; * Subjects with only skin and/or brain lesions as target lesions * Combined diseases and medical history 1. Have had or currently have other malignant tumors within the past 5 years of randomization 2. Unrelieved toxic reactions above Common Terminology Criteria (CTC) AE grade 1 caused by any previous treatment 3. Received major surgical treatment, open biopsy, or significant traumatic injury within 4 weeks prior to randomization 4. There are diseases that affect intravenous injection and venous blood collection 5. There are congenital bleeding and coagulation disorders present 6. An arterial/deep vein thrombosis event occurred within 6 months prior to the first administration 7. Poor blood pressure control 8. Suffering from significant cardiovascular disease 9. There is an uncontrolled infection of ≥ CTC AE grade 2 within 14 days before the start of treatment 10. History of interstitial lung disease/pneumonia (non infectious) requiring steroid medication intervention in the past 11. Individuals with moderate to severe pulmonary dysfunction/disease within 3 months prior to the first administration 12. Active viral hepatitis with poor control 13. Active syphilis infected individuals in need of treatment 14. Individuals who are preparing for or have previously undergone allogeneic bone marrow transplantation or solid organ transplantation 15. Immunosuppressants or systemic or absorbable local hormone therapy are required to achieve immunosuppression 16. History of immunodeficiency, including HIV positivity or other acquired or congenital immunodeficiency diseases 17. Urine routine shows urinary protein ≥++and confirms 24-hour urinary protein quantification\>1.0 g 18. Patients with renal failure requiring hemodialysis or peritoneal dialysis 19. Poor control of diabetes 20. Individuals with epilepsy who require treatment 21. Individuals with a history of abuse of psychotropic drugs who are unable to quit or have mental disorders * Tumor related symptoms and treatment 1. There is a third interstitial fluid accumulation or cancerous lymphangitis that cannot be controlled by drainage or other methods 2. History of cumulative dose exposure to anthracyclines in the past 3. Received radiation therapy within 3 weeks prior to the start of study treatment and endocrine therapy within 2 weeks prior to the start of study treatment 4. Traditional Chinese patent medicines and simple preparations with anti-tumor indications specified in the National Medical Products Administration (NMPA) approved drug instructions within 2 weeks before the start of the study treatment * Research treatment related 1. Previously received antibody conjugate therapy consisting of topoisomerase I inhibitors,; 2. Allergic to any research drug or any ingredient or excipient in the drug; 3. Individuals who experience severe hypersensitivity reactions after using monoclonal antibodies; 4. Participated in other clinical trials of anti-tumor therapy within 4 weeks before the start of the research treatment. * According to the researcher's judgment, there are situations that seriously endanger the safety of the subjects or affect their ability to complete the study.