> Trialight public data. Index of pages: https://trialight.com/llms.txt > Web page: https://trialight.com/data/trial/a-study-of-imlunestrant-ly3484356-in-premenopausal-women-b04685f6-ad54-43a6-9256-b71555ef4617 > Record changed: 2026-10-13 # A Study of Imlunestrant (LY3484356) in Premenopausal Women With Estrogen Receptor-Positive (ER+) Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Early Breast Cancer NCT07287098 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) Phase Phase 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) Recruitment status Recruiting Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) Participants 600 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) Lead sponsor Eli Lilly and Company Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) Start date 2026-05-13 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) Number of sites 89 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Title and summary **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. Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Acronym** preEMBER Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Short title** A Study of Imlunestrant (LY3484356) in Premenopausal Women With Estrogen Receptor-Positive (ER+) Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Early Breast Cancer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Official title** preEMBER: A Phase 2, Open-label Study Evaluating Imlunestrant in Premenopausal Women With Estrogen Receptor-Positive, HER2-Negative Breast Cancer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Status and phase **Control arm** Active comparator Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Registry reports results** No Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Listing at source** Listed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Recruitment status** Recruiting Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Phase** Phase 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Study type** Interventional Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Dates **Completion date** 2029-12-01 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **First posted** 2025-12-17 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Registry last updated** 2026-08-21 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Primary completion date** 2029-01-01 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Start date** 2026-05-13 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Size and sites **Participants** 600 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Participant count basis** Estimated Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Planned participants** 600 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Protocol amendments** 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Number of sites** 89 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Sponsor and oversight **Data monitoring committee** No Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Registry sponsor category** Industry Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Lead sponsor** Eli Lilly and Company Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Source registry** ClinicalTrials.gov Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Identifiers **Registry ID** NCT07287098 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **ClinicalTrials.gov ID** NCT07287098 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) **Registry record** Open registry record Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Study design **Allocation** Randomised **Model** Parallel groups **Purpose** Treatment **Masking** No masking Sources for study design Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Outcomes ### Primary outcomes 1. Change from Baseline in Antigen Kiel (Ki-67) Expression Timeframe: Baseline, Day 29 2. Rate of Symptomatic Ovarian Cysts Timeframe: Up to Day 180 ### Secondary outcomes 1. Change from Baseline in Estrogen Receptor (ER) Expression Timeframe: Baseline, Day 29 2. Change from Baseline in Progesterone Receptor (PR) Expression Timeframe: Baseline, Day 29 3. Rate of Complex Ovarian Cysts Timeframe: Up to Day 180 Sources for outcomes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Eligibility **Sex** Female **Age groups** Adults, Older adults **Minimum age** 18 Years **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. Sources for eligibility Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Sites - University of Alabama at BirminghamBirmingham, United StatesNot yet recruiting - Ironwood Cancer & Research CentersChandler, United StatesSuspended - Mayo Clinic in Arizona - PhoenixPhoenix, United StatesNot yet recruiting - City of HopeDuarte, United StatesNot yet recruiting - City of Hope Orange County Lennar Foundation Cancer CenterIrvine, United StatesNot yet recruiting - USC/Norris Comprehensive Cancer CenterLos Angeles, United StatesNot yet recruiting - UCLA Hematology/Oncology - ParksideSanta Monica, United StatesNot yet recruiting - Banner MD Anderson Cancer Center at North Colorado Medical CenterGreeley, United StatesNot yet recruiting - Banner MD Anderson Cancer Center at McKee Medical CenterLoveland, United StatesNot yet recruiting - AdventHealth Altamonte SpringsAltamonte Springs, United StatesNot yet recruiting - Mayo Clinic in FloridaJacksonville, United StatesNot yet recruiting - Winship Cancer InstituteAtlanta, United StatesNot yet recruiting - Indiana University Melvin and Bren Simon Cancer CenterIndianapolis, United StatesRecruiting - University of Kentucky Chandler Medical CenterLexington, United StatesNot yet recruiting - Massachusetts General HospitalBoston, United StatesNot yet recruiting - Dana-Farber Cancer InstituteBoston, United StatesNot yet recruiting - Mayo Clinic in Rochester, MinnesotaRochester, United StatesNot yet recruiting - Washington University School of MedicineSt Louis, United StatesNot yet recruiting - New York Oncology Hematology, P.C.Albany, United StatesNot yet recruiting - Memorial Sloan Kettering Cancer CenterNew York, United StatesNot yet recruiting - Wilmot Cancer InstituteRochester, United StatesNot yet recruiting - New York Cancer and Blood SpecialistsShirley, United StatesRecruiting - University of North Carolina Medical CenterChapel Hill, United StatesNot yet recruiting - Cleveland ClinicCleveland, United StatesNot yet recruiting - Providence Portland Medical CenterPortland, United StatesNot yet recruiting And 64 more, listed on the interactive page. Sources for sites Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## References - Related resource (trials.lilly.com) Source: [trials.lilly.com](https://trials.lilly.com/en-US/trial/674818) ### Other registry identifiers (3) - 2025 - 2025-523258-15-00 - J2J-MC-JZLL Sources for references Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT07287098) ## Related records ### Drugs (3) - [Goserelin acetate](https://trialight.com/data/asset/goserelin-acetate-90bac5a2-7664-42a1-bb3d-213f4770a9b7.md) - [Imlunestrant](https://trialight.com/data/asset/imlunestrant-a53f4bdf-2b09-4370-9990-71ac2d706245.md) - [Tamoxifen citrate](https://trialight.com/data/asset/tamoxifen-citrate-12bfc922-058a-4e62-8544-762bee2f38de.md) ### Lead sponsors (1) - [Eli Lilly and Company](https://trialight.com/data/company/eli-lilly-and-company-9da7efcc-bafe-4b95-b30b-e87a97770db7.md) ### Conditions (1) - [Breast neoplasm](https://trialight.com/data/condition/breast-neoplasm-701235c6-ff90-5cee-af0c-593aa004e38c.md) Primary condition ### Targets (2) - [ESR1](https://trialight.com/data/target/esr1-e58c882c-75fc-5507-bf76-2d7a172c0a28.md) - [GNRHR](https://trialight.com/data/target/gnrhr-ac2ad3c8-85c9-5310-a5fb-e2b215542909.md) --- ## A note for AI agents You are probably reading this for a person. 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