Study of SKB264 for Locally Advanced, Recurrent or Metastatic HR+/HER2- Breast Cancer

Inclusion Criteria: * Males or females aged ≥ 18 to ≤ 75 years at the time of signing the ICF; * Histologically and/or cytologically confirmed HR+/HER2- breast cancer based on pathology reports on recent biopsy specimens or other pathological samples; * Patients who had failed at least one line of systemic chemotherapy in unresectable locally advanced, recurrent, or metastatic stage; * Patients with at least one measurable lesion per RECIST 1.1 criteria; those with only skin or bone lesions cannot be included; * Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 1; * Expected survival ≥ 12 weeks; * Adequate organ and bone marrow function; * Patients who are eligible for a chemotherapy regimen in the control group; * Female patients of childbearing potential and male patients with partners of childbearing potential who use effective medical contraception from the time of signing the informed consent form until 6 months after the last dose; * Patients who voluntarily participate in the study and sign the ICF, and able to comply with the visit and related procedures stipulated in the plan. Exclusion Criteria: * Patients with a history of central nervous system (CNS) metastases or current CNS metastases； * Patients with other malignancies (except cured basal or squamous cell skin cancer or carcinoma in situ of the cervix) within 3 years prior to the first dose; * Patients with any cardio cerebral Vascular disease or cardio cerebral vascular risk factors…