A Phase 1 Study of HRS8807 Monotherapy and in Combination With SHR6390 in Subjects With ER-Positive, HER2-Negative Metastatic or Locally Advanced Breast Cancer

Inclusion criteria

• Histological diagnosis of metastatic or locally advanced breast cancer; Histologically proven diagnosis of ER-positive, HER2-negative;
• At least 1 line of endocrine therapy in the metastatic or advanced setting that had progressed or intolerance; ≤ 2 lines of chemotherapy for metastatic or advanced disease;
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 or 1;
• Expected survival of more than 3 months.

Exclusion criteria

• All patients in monotherapy and or in combination wih phase who are known allergic to HRS8807 or SHR6390 ingredient;
• Presence of symptomatic metastatic visceral disease ;
• Patients with known active brain metastases;
• Clinically serious cardiovascular disease;
• Abnormal electrocardiographic (ECG) with clinical significancy by investigator judgement;
• Abnormal thyroid function laboratory results;
• Active infection or unexplained fever >38.5℃ during screening period or on the day of the first dose.