Real-world Patient-reported Outcome of Sacituzumab Govitecan in Chinese Metastatic Breast Cancer

Inclusion criteria

• Patients aged 18 to 75 years.
• Patients have been diagnosed with metastatic HER2 negative breast cancer. HER2 status were determined locally by immunohistochemistry (IHC) of patients' primary or metastatic tumor sections. HER2-negative status was defined by IHC staining 0 to 1+ or fluorescence in situ hybridization ratio \<2.0 if IHC 2+ or IHC not performed.
• The metastatic disease was confirmed by clinical, imaging, histological, or cytological measures, including unresectable locally advanced breast cancer, de novo stage IV breast cancer, and recurrent metastatic breast cancer.
• ECOG-PS ≤2
• For patients with triple-negative breast cancer (TNBC): at least 1 line of systemic therapy in the metastatic setting; for patients with HR+/HER2- breast cancer: prior treatment with endocrine therapy and CDK4/6 inhibitors, and at least 1 line of systemic therapy in the metastatic setting.
• At least one evaluable lesion by CT or MRI according to RECIST 1.1.
• Willing to accept the treatment by the investigator based on the patient's preference, physical condition, prior treatment history, and financial circumstances.
• Willing to use contraceptive measures during the study period.
• Willing and able to complete electronic questionnaires/scales on a smartphone, tablet, or other electronic device.
• All patients can provide an informed consent before enrolment and data collection.

Exclusion criteria

• Insufficient bone marrow, hepatic, or renal function, defined as:
• Bone marrow: White blood cell count \< 3.0 × 10⁹/L, or absolute neutrophil count \< 1.5 × 10⁹/L, or platelet count \< 75 × 10⁹/L, or hemoglobin \< 8.0 g/dL.
• Hepatic function: Total bilirubin \> 1.5 × upper limit of normal (ULN), or ALT/AST \> 3.0 × ULN (or \> 5.0 × ULN in the presence of liver metastases).
• Renal function: Serum creatinine \> 1.5 × ULN, or creatinine clearance \< 50 mL/min.
• History of other malignancies or hematologic malignancies.
• Hypersensitivity to the study treatment drugs.
• Systemic anti-tumor therapy (including chemotherapy, radiotherapy, immunotherapy, etc.) within 2 weeks prior to study drug administration.
• Treatment with an investigational product within 4 weeks before the first treatment.
• Presence of any toxicity from prior therapy (excluding alopecia) ≥ Grade 2 according to CTCAE version 5.0, prior to study drug administration.
• Systemic inflammatory diseases, including but not limited to systemic lupus erythematosus, juvenile chronic arthritis, spondyloarthropathy, Crohn's disease, ulcerative colitis, psoriatic arthritis, or active vasculitis.
• Severe psychiatric or neurological disorders, including but not limited to schizophrenia, depression, mania, Alzheimer's disease, myasthenia gravis, seizure disorders, or known conditions that may provoke seizures.
• Pregnant or breastfeeding women.