Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have Not Received Anticancer Treatment for Advanced/Metastatic Disease
The purpose of this study is to determine the safety and efficacy of PF-07220060 with letrozole compared to approved treatments (ie, palbociclib, ribociclib or abemaciclib with letrozole) in people with breast cancer:
* HR-positive (breast cancer cells that need estrogen or progesterone to grow)
* HER2-negative (cells that have a small amount or none of a protein called HER2 on their surface);
* locally advanced (that has spread from where it started to nearby tissue or lymph nodes) or metastatic disease (the spread of cancer to other places in the body)
* who have not received any prior syst