This study is for people with a specific type of breast cancer called estrogen receptor-positive (ER+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer. This cancer has spread to other parts of the body or is too advanced to be removed by surgery. The goal is to test how well a new treatment, giredestrant combined with everolimus, works compared to the doctor’s choice of hormone therapy with everolimus. Participants must have already tried other treatments like endocrine therapy (ET) and CDK4/6 inhibitors, which help slow down cancer cell growth.

Key points:

• This study involves taking medication and regular check-ups to monitor health.
• The study may have risks and side effects, so it's important to talk to your doctor.
• Participants cannot have used certain medications or have certain health conditions.

People cannot join if they have had certain other treatments, have more than two previous hormone therapy treatments, or have specific health issues like uncontrolled brain metastases or severe heart problems. The study needs blood samples for testing. Pregnant or breastfeeding individuals cannot participate.