A Phase II Study to Evaluate the Efficacy and Safety of HLX43 in Patients With Hormone Receptor Positive, HER2 Negative Locally Advanced or Metastatic Breast Cancer

This is a Phase II Study of HLX43 in Hormone Receptor Positive，HER-2 negative Locally Advanced or Metastatic Breast Cancer Patients with Disease Progression on Standard of Care. Eligible subjects will be treated with the study drug until the loss of clinical benefit, death, intolerable toxicity, withdrawal of informed consent, or other reasons specified by the protocol (whichever occurs first)