About the Study
The main purpose of this study is to test a potential new treatment for early breast cancer. The study will measure how well a new hormone therapy (imlunestrant) works compared to standard hormone therapy in participants with early breast cancer that is estrogen receptor positive (ER+) and human epidermal receptor 2 negative (HER2-).
Who Can Participate
- 18+
- Have a diagnosis of ER+, HER2- early-stage, resected, invasive breast cancer without evidence of distant metastasis.
- Must have already taken endocrine therapy for two to five years and must have a higher-than-average risk for cancer to return.
What to Expect During Study Participation
The duration of your participation depends on how well your disease responds to the study treatment. Your participation in this study is expected to last up to 10 years (5-year treatment phase and a 5-year posttreatment phase).
During the treatment period, you will need to attend the site for at least 18 visits (13 clinic visits and 5 phone visits) over 5 years. Each visit may be different in length depending on what tests will be done. Your study doctor will explain what you have to do and which tests you will have during the study. Each visit will take between 1-4 hours.
Study Medication
The study is a randomised, open-label trial. There are two treatment groups. You will have an equal chance (1 in 2) of being randomly assigned to one of the two treatment groups. Open-label means both you and your study doctor will know which treatment you are receiving after randomisation.
The two treatment groups are:
• Arm A: 400 mg imlunestrant
• Arm B: anastrozole OR letrozole OR exemestane OR tamoxifen
