Participate in Research at CU Anschutz

The main purpose of this study is to measure how well 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-). Participants must have already taken endocrine therapy for two to five years and must have a higher-than-average risk for their cancer to return. Study participation could last up to 10 years.

This study plans to learn more about how safe an investigational drug known as imlunestrant is and how well it will work to help people with Estrogen receptor positive (ER+), human epidermal growth factor receptor 2-negative (HER2-), early breast cancer with an increased risk of recurrence as compared to endocrine therapy. “Investigational” means that the study drug has not been approved by the U.S. Food and Drug Administration (FDA). Endocrine therapy drugs used in this study include anastrozole, letrozole, tamoxifen and exemestane. They are all approved for adjuvant breast cancer treatment. Patients with estrogen receptor positive (ER+) early breast cancer receive estrogen signaling blocking agents (anti-estrogens) as standard of care for their disease. Estrogen signaling plays an important role in organ development and growth. In certain cancers, abnormal estrogen signaling through the estrogen receptor is a key component of tumor growth. Disruption of estrogen signaling by drugs called selective estrogen receptor degraders (SERDs) is one of the treatment options for patients with estrogen receptor positive (ER+) cancers. Imlunestrant is a SERD that disrupts estrogen signaling, and therefore should stop or slow down tumor growth in ER+ cancers. The main reason for you to take part in this study is not to necessarily treat you for your condition but to help in answering the following research questions: The safety of imlunestrant and any side effects you might have when you take it. Whether imlunestrant can help study participants with early breast cancer. How imlunestrant compares to standard-of-care endocrine therapy. You are being asked to be in this research study because you have ER+, HER2- early breast cancer.