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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
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07287098
Acronym
preEMBER
Enrollment
600
Registered
2025-12-17
Start date
2026-05-01
Completion date
2029-12-01
Last updated
2026-03-27

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast Neoplasms

Brief 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.

Interventions

Given orally

DRUGGoserelin

Given SC

Given orally

Sponsors

Eli Lilly and Company
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

Cohort 1: * Have histologically confirmed Stage I to III Estrogen Receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) invasive breast carcinoma with Ki-67 at least 10% * Be willing and able to provide pre- and on-treatment tumor samples. * Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Be able to swallow capsules or tablets. * Be premenopausal women. * If of childbearing potential must use 1 highly effective method of non-hormonal contraception while receiving study treatment and for the duration specified in protocol. * Have adequate organ function. Cohort 2: * Have a diagnosis of ER+, HER2- early-stage, resected, invasive breast cancer without evidence of distant metastasis * Have undergone definitive loco-regional therapy. * Have received at least 4.5 years of any adjuvant endocrine therapy (ET), or at least 2 years of adjuvant ET with no additional ovarian suppression planned. * Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Be able to swallow capsules or tablets. * Be premenopausal women * If of childbearing potential must use 1 highly effective method of non-hormonal contraception while receiving study treatment and for the duration specified in protocol. * Have adequate organ function.

Exclusion criteria

Cohort 1: * Have bilateral invasive metastatic, occult primary, or inflammatory breast cancer. * Have had prior bilateral oophorectomy or ovarian ablation. * Have a serious medical condition * Had major surgery within 28 days prior to randomization. * Have a history of other cancer (except non melanoma skin cancer, Stage I uterine cancer, or carcinoma in situ of the cervix or other in situ cancer), unless in complete remission with no therapy for a minimum of 1 year. * Plan to receive concurrent neoadjuvant therapy with any other non-protocol anticancer therapy. * Have had any prior therapy for an invasive or non-invasive breast cancer. * Have had prior radiotherapy to the ipsilateral chest wall for any malignancy. * Have received prior anti-estrogen therapy, including for osteoporosis or prevention of breast cancer. * Have had prior treatment with any Gonadotropin-releasing hormone (GnRH) agonist within 12 months prior to randomization. * Receiving current exogenous reproductive hormone therapy Cohort 2: * Have ovarian cyst(s) greater than (\>) 1 centimeter (cm) at screening. * Have metastatic occult primary, or inflammatory breast cancer. * Have had prior bilateral oophorectomy or ovarian ablation. * Have a serious medical condition * Had major surgery within 28 days prior to randomization. * Have a history of other cancer (except non melanoma skin cancer or carcinoma in situ of the cervix or other in situ cancer), unless in complete remission with no therapy for a minimum of 1 year. * Completed or discontinued prior adjuvant ET \>6 months prior to screening. * Have received prior therapy with any selective estrogen receptor degrader (SERD). * Receiving current exogenous reproductive hormone therapy.

Design outcomes

Primary

MeasureTime frame
Change from Baseline in Antigen Kiel (Ki-67) ExpressionBaseline, Day 29
Rate of Symptomatic Ovarian CystsUp to Day 180

Secondary

MeasureTime frame
Change from Baseline in Estrogen Receptor (ER) ExpressionBaseline, Day 29
Change from Baseline in Progesterone Receptor (PR) ExpressionBaseline, Day 29
Rate of Complex Ovarian CystsUp to Day 180

Countries

Belgium, France, Germany, Italy, United States

Contacts

CONTACTTrial questions or participation questions: 1-877-CTLILLY (1-877-285-4559) or
LillyTrials@Lilly.com1-317-615-4559
CONTACTPhysicians interested in becoming principal investigators please contact
clinical_inquiry_hub@lilly.com
STUDY_DIRECTORCall 1-877-CTLILLY (1-877-285-4559) or 1-317-615-4559 Mon - Fri 8 AM - 8 PM Eastern time (UTC/GMT - 5 hours, EST)

Eli Lilly and Company

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 28, 2026