TQB2930 Injection for the Treatment of HER2-positive Advanced Breast Cancer

Inclusion Criteria:

* Subjects voluntarily participate in this study and sign the informed consent form;
* Age: 18-75 years (at time of signing Informed Consent Form (ICF); Eastern Cooperative Oncology Group (ECOG) performance status ≤1; estimated life expectancy \>3 months;
* Cytologically or histologically confirmed Human Epidermal Growth Factor Receptor 2 (HER2)-positive recurrent or metastatic breast cancer;
* Received ≥2 prior lines of anti-HER2 targeted therapy in the advanced setting;
* At least one measurable lesion meeting Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST 1.1) criteria (excluding brain lesions);
* Willing to receive one of the investigator-selected chemotherapy regimens;
* Adequate organ function;
* Female subjects of childbearing potential must agree to use effective contraception (e.g., Intrauterine Device (IUD), oral contraceptives, or condoms) during the study and for 6 months after study completion.

Exclusion Criteria:

* Concurrent Diseases and Medical History:

  * Other malignancies within 5 years before randomization or concurrent malignancies (except adequately treated non-melanoma skin cancer, in situ cervical cancer, or other cancers with curative treatment and no recurrence for ≥3 years);
  * Uncontrolled toxicities (\>CTCAE Grade 1) from prior therapies (excluding alopecia);
  * Major surgery, open biopsy, or significant traumatic injury within 28 days before randomization;
  * Non-healing wounds or fractures;
  * Arterial/venous thromboembolic events within 6 months before randomization;
  * History of drug abuse or psychiatric disorders that may affect compliance;
  * Poorly controlled hypertension (e.g., Systolic Blood Pressure (SBP) \>160 mmHg despite treatment);
  * ≥Grade 2 myocardial ischemia/infarction, arrhythmias, or congestive heart failure (New York Heart Association （NYHA）Class ≥II);
  * Active or uncontrolled severe infections (≥CTCAE Grade 2);
  * Known chronic hepatitis B;
  * Active syphilis infection;
  * Renal failure requiring hemodialysis/peritoneal dialysis;
  * Immunodeficiency disorders (e.g., Human Immunodeficiency Virus (HIV) ;
  * Poorly controlled diabetes;
  * Urine protein ≥++ on dipstick with 24-hour urine protein \>1.0 g;
  * Epilepsy requiring medication.
* Tumor-Related Conditions and Treatments:

  * Chemotherapy, radiotherapy, or immunotherapy within 4 weeks before randomization (or within 5 half-lives of prior drugs, whichever is shorter);
  * Chinese herbal medicines with approved antitumor indications (per National Medical Products Administration (NMPA) labeling) within 2 weeks;
  * Severe Bone Lesions from bone metastases;
  * Untreated brain metastases, Leptomeningeal metastases, or carcinomatous meningitis;
  * Prior HER2-targeted therapy-induced Left Ventricular Ejection Fraction (LVEF) decline to \<50% or absolute reduction \>15%;
  * Uncontrolled or symptomatic Hypertension requiring ongoing bisphosphonates;
  * Uncontrolled cancer-related pain;
  * Existed Lymphangitis Carcinomatosa or uncontrolled effusions;
  * Use of Immunosuppressant or systemic corticosteroids (≥10 mg/day prednisone equivalent) within 2 weeks.
* Severe hypersensitivity to monoclonal antibodies;
* Participation in other antitumor clinical trials with investigational drugs within 4 weeks before randomization;
* Any condition deemed by the investigator to jeopardize subject safety or study completion.