A Study to Learn About the Study Medicine Called Vepdegestrant (ARV-471, PF-07850327) in People With ER+/HER2- Advanced Breast Cancer in China

The purpose of this clinical trial is to learn about the pharmacokinetics. safety and tolerability of the study medicine (called ARV-471) for the potential treatment of advanced estrogen receptor postive and human epidermal growth factor receptor 2 negative breast cancer. This study is seeking participants have * ER+/HER2- advanced breast cancer * received at least 1 line of endocrine therapy with or without CDK4/6 inhibitor * received up to 2 prior regimens of chemotherapy for advanced setting. All participants in this study will receive ARV-471. ARV-471 will be given by mouth at home once a day. The experiences of people receiving the study medicine will be examined. This will help determine if the study medicine is safe and effective. Participants will take part in this study until their cancer is no longer responding. During this time, they will have visits at the study clinic about every 4 weeks.