NCT07287098

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

preEMBER: A Phase 2, Open-label Study Evaluating Imlunestrant in Premenopausal Women With Estrogen Receptor-Positive, HER2-Negative Breast Cancer

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 600 (estimated)
• Sponsor: Eli Lilly and Company · Industry
• Sex: Female
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

This study will include two groups of patients: Cohort 1 and Cohort 2. Cohort 1: will help researchers learn how a medicine called imlunestrant (LY3484356) affects a specific type of breast cancer. Some patients will take both imlunestrant and another treatment to suppress their ovarian function. Some will take it without ovarian suppression. Researchers will compare the effects in breast cancer cells to those of another medicine called tamoxifen. All patients in this group will be premenopausal women who have a type of early breast cancer called estrogen receptor-positive, HER2-negative. The treatment in this group will last for up to 29 days. Cohort 2: will help researchers understand how imlunestrant affects the ovaries when it is taken without ovarian suppression. Researchers will compare the effects to those of another medicine called tamoxifen. This group will also include premenopausal women with the same type of breast cancer. The treatment in this group will last for up to 6 months.

Conditions

• Breast Neoplasms

Interventions

Type	Name	Description
DRUG	Imlunestrant	Given orally
DRUG	Goserelin	Given SC
DRUG	Tamoxifen 20 mg	Given orally

Timeline

• Start date: 2026-05-01
• Primary completion: 2029-01-01
• Completion: 2029-12-01
• First posted: 2025-12-17
• Last updated: 2026-04-17

Locations

42 sites across 6 countries: United States, Belgium, France, Germany, Italy, Taiwan

Regulatory

• FDA-regulated drug study