The purpose of this study is to evaluate the efficacy and safety of SKB264 in patients with unresectable locally advanced, recurrent, or metastatic HR+/HER2- breast cancer who have previously failed endocrine therapy.
Aged ≥ 18 and ≤ 75 years at the time of signing the ICF, male or female;
Histologically and/or cytologically confirmed HR+/HER2- BC based on pathological reports from the most recent biopsy or other pathological specimens;
Subjects must have radiologically documented disease progression during or after the most recent treatment prior to enrollment;
No prior systemic chemotherapy for locally advanced, relapsed, or metastatic stages. Subjects who previously received adjuvant/neoadjuvant chemotherapy and progressed >6 months after completion of the last chemotherapy treatment will be allowed for study inclusion;
Subjects with locally advanced breast cancer suitable for curative therapy at study enrollment;
Other malignancies (except those tumors cured by local treatment, such as basal cell carcinoma of skin, squamous cell carcinoma of skin, carcinoma in situ of the cervix) within 3 years prior to randomization;
Subiects with known meningeal metastases, brainstem metastases, spinal cord metastases and/or compression or active centralnervous system (CNS) metastases.
Presence of any serious cardiovascular and cerebrovascular diseases or cardiovascular and cerebrovascular risk factors;