This study aims to evaluate the safety, tolerability, efficacy and pharmacokinetics of HRS-6208 in combination with HRS-8080 ± HRS-6209, or in combination with fulvestrant ± HRS-6209, or in combination with letrozole ± HRS-6209 in patients with advanced unresectable or metastatic breast cancer.
Female, aged 18-75 (inclusive);
ECOG score 0-1;
Estimated survival time ≥ 12 weeks;
Possessing adequate bone marrow and organ function;
Within 5 years prior to the first dose of study medication, the occurrence of other malignancies, except for fully treated cervical carcinoma in situ, basal cell or squamous cell skin cancer, and post-radical surgery thyroid papillary carcinoma;
Active brain metastasis, carcinomatous meningitis, spinal cord compression, or history of primary central nervous system tumors;
Severe bone damage caused by tumor bone metastasis as determined by the investigator;
Adverse events caused by previous anti-tumor treatment have not been resolved;