Study of Imlunestrant in Premenopausal Women With Early Estrogen Receptor-Positive, HER2-Negative Breast Cancer

What this Trial Is About

Researchers are evaluating the effects of the drug imlunestrant LY3484356 in premenopausal women with early estrogen receptor-positive ER, HER2-negative breast cancer. The study includes two groups one that explores imlunestrant alone or combined with ovarian suppression, and another that studies imlunestrant without ovarian suppression. The trial compares imlunestrants impact on breast cancer cells and ovarian function to tamoxifen, a known treatment. Participants in Cohort 1 will receive imlunestrant orally either alone or with goserelin a drug given by injection to suppress ovarian function for up to 29 days. Some in this group will take tamoxifen orally as a comparator. Cohort 2 participants will take imlunestrant or tamoxifen orally for up to 6 months without ovarian suppression. The study is open-label, randomized, and phase 2, designed to assess treatment effects in parallel groups. During the study, participants will provide tumor samples before and during treatment, and researchers will monitor changes in specific cancer markers like Ki-67, estrogen receptor ER, and progesterone receptor PR expression. They will also track the rate of ovarian cysts up to 180 days. Participants must attend scheduled visits for evaluations, including performance status checks and safety assessments. The trial is expected to continue until December 2029.

A Study of Imlunestrant (LY3484356) in Premenopausal Women With Estrogen Receptor-Positive (ER+) Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Early Breast Cancer