New pill could offer hope for younger breast cancer patients

NCT ID NCT07287098

Disease control Sponsor: Eli Lilly and Company Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Sep 04, 2026 · Updated 7 times

Summary

This study tests a new oral drug called imlunestrant in premenopausal women with estrogen receptor-positive, HER2-negative breast cancer. Some participants will also receive a drug to suppress ovarian function. The effects on tumor cells and ovaries will be compared with those of tamoxifen, a standard treatment. The trial has two groups: one treated for up to 29 days and another for up to 6 months, involving 600 women total.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance: Imlunestrant (a drug taken orally) and goserelin (a drug to suppress ovarian function), compared with tamoxifen
What this could lead to: If successful, this could point toward a new treatment option for premenopausal women with a common type of breast cancer, potentially offering an alternative to tamoxifen.
What could go wrong: This is an early Phase 2 study with only short-term outcomes (up to 6 months). It's not designed to prove long-term benefit, and the drug may not work better or may have side effects not yet seen.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 2

Tests whether the treatment actually works, and watches for side effects, in a larger group.

Participants

About 600 people

The number the study aims to enrol. It can still change while the study runs.

Started

May 2026

Expected to finish

Dec 2029

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 years and older

Sex

Female participants only

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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.

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Conditions

The condition(s) this trial relates to.

breast neoplasm estrogen-receptor positive breast cancer hormone receptor-positive breast cancer

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Breast neoplasm female Breast neoplasms

How to take part

Only the study team decides who joins. These are the ways to reach them.

The places running it

89 sites in 7 countries. The list below names each one and where it is.
The official record

ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

Open the record ↗
A doctor treating you

A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Contacts and locations

Locations

AdventHealth Altamonte Springs
NOT_YET_RECRUITING

Altamonte Springs, Florida, 32701, United States
Agaplesion Markus Krankenhaus
NOT_YET_RECRUITING

Frankfurt, 60431, Germany
Antwerp University Hospital
NOT_YET_RECRUITING

Edegem, 2650, Belgium
Augusta-Kranken-Anstalt
NOT_YET_RECRUITING

Bochum, 44791, Germany
Banner MD Anderson Cancer Center at McKee Medical Center
NOT_YET_RECRUITING

Loveland, Colorado, 80538, United States
Banner MD Anderson Cancer Center at North Colorado Medical Center
NOT_YET_RECRUITING

Greeley, Colorado, 80631, United States
Baylor Scott & White Medical Center - Round Rock
NOT_YET_RECRUITING

Round Rock, Texas, 78665, United States
CHRU de Brest
NOT_YET_RECRUITING

Brest, 29609, France
Centre de Cancérologie du Grand Montpellier
NOT_YET_RECRUITING

Montpellier, 34070, France
Chang Gung Medical Foundation-Linkou Branch
NOT_YET_RECRUITING

Taoyuan, 333, Taiwan
China Medical University Hospital
NOT_YET_RECRUITING

Taichung, 404332, Taiwan
City of Hope
NOT_YET_RECRUITING

Duarte, California, 91010, United States
City of Hope Orange County Lennar Foundation Cancer Center
NOT_YET_RECRUITING

Irvine, California, 92618, United States
Cleveland Clinic
NOT_YET_RECRUITING

Cleveland, Ohio, 44195, United States
Cliniques universitaires Saint-Luc
NOT_YET_RECRUITING

Brussels, 1200, Belgium
Dana-Farber Cancer Institute
NOT_YET_RECRUITING

Boston, Massachusetts, 02215, United States
Ente Ospedaliero Ospedali Galliera
NOT_YET_RECRUITING

Genova, 16128, Italy
Evangelisches Krankenhaus Bergisch Gladbach
NOT_YET_RECRUITING

Bergisch Gladbach, 51465, Germany
Evangelisches Krankenhaus Bethesda Mönchengladbach
NOT_YET_RECRUITING

Mönchengladbach, 41061, Germany
Fondazione Policlinico Universitario Agostino Gemelli
NOT_YET_RECRUITING

Roma, 00168, Italy
Frauenärzte am Bahnhofsplatz
RECRUITING

Hildesheim, 31134, Germany
Galway University Hospital
NOT_YET_RECRUITING

Galway, H91 YR71, Ireland
Gemeinschaftspraxis Hämatologie - Onkologie Freiberg-Richter, Jacobasch, Illmer, Wolf
NOT_YET_RECRUITING

Dresden, 01307, Germany
Gustave Roussy
NOT_YET_RECRUITING

Villejuif, 94800, France
Gynaekologisches Zentrum Bonn
NOT_YET_RECRUITING

Bonn, 53111, Germany
HELIOS Klinikum Wuppertal
NOT_YET_RECRUITING

Wuppertal, 42283, Germany
Helios HSK Wiesbaden
NOT_YET_RECRUITING

Wiesbaden, 65199, Germany
Houston Methodist Hospital
NOT_YET_RECRUITING

Houston, Texas, 77030, United States
Humanitas
NOT_YET_RECRUITING

Milan, 20089, Italy
Humanitas Istituto Clinico Catanese
NOT_YET_RECRUITING

Misterbianco, 95045, Italy
Huntsman Cancer Institute
NOT_YET_RECRUITING

Salt Lake City, Utah, 84112, United States
Hôpital Privé Des Côtes d'Armor
NOT_YET_RECRUITING

Plérin, 22190, France
Indiana University Melvin and Bren Simon Cancer Center
RECRUITING

Indianapolis, Indiana, 46202, United States
Inova Schar Cancer Institute
NOT_YET_RECRUITING

Fairfax, Virginia, 22031, United States
Institut Curie - site Saint-Cloud
NOT_YET_RECRUITING

Saint-Cloud, 92210, France
Ironwood Cancer & Research Centers
SUSPENDED

Chandler, Arizona, 85224, United States
Istituto Europeo di Oncologia IRCCS
NOT_YET_RECRUITING

Milan, 20141, Italy
Kaohsiung Medical University Chung-Ho Memorial Hospital
NOT_YET_RECRUITING

Kaohsiung City, 807, Taiwan
Klinik Weinheim
NOT_YET_RECRUITING

Weinheim, 69469, Germany
Kliniken Essen-Mitte, Evangelische Huyssens-Stiftung
NOT_YET_RECRUITING

Essen, 45136, Germany
Klinikum Ernst von Bergmann
NOT_YET_RECRUITING

Potsdam, 14467, Germany
Klinikum Mutterhaus der Borromäerinnen
RECRUITING

Trier, 54290, Germany
Klinikum der Ludwig-Maximilians-Universitaet Muenchen
NOT_YET_RECRUITING

München, 80336, Germany
Krankenhaus Köln-Holweide
NOT_YET_RECRUITING

Cologne, 51067, Germany
MVZ für Hämatologie und Onkologie Ravensburg GmbH - Studienzentrum
NOT_YET_RECRUITING

Ravensburg, 88212, Germany
Mackay Memorial Hospital
NOT_YET_RECRUITING

Taipei, 10449, Taiwan
Mammazentrum HH - Krankenhaus Jerusalem
NOT_YET_RECRUITING

Hamburg, 20357, Germany
Marien Hospital Witten
NOT_YET_RECRUITING

Witten, 58452, Germany
Marienhospital Bottrop
NOT_YET_RECRUITING

Bottrop, 46236, Germany
Massachusetts General Hospital
NOT_YET_RECRUITING

Boston, Massachusetts, 02114, United States
Mayo Clinic in Arizona - Phoenix
NOT_YET_RECRUITING

Phoenix, Arizona, 85054, United States
Mayo Clinic in Florida
NOT_YET_RECRUITING

Jacksonville, Florida, 32224, United States
Mayo Clinic in Rochester, Minnesota
NOT_YET_RECRUITING

Rochester, Minnesota, 55905, United States
Medizinische Universität Lausitz- Carl Thiem
NOT_YET_RECRUITING

Cottbus, 03048, Germany
Memorial Sloan Kettering Cancer Center
NOT_YET_RECRUITING

New York, New York, 10065, United States
National Cheng Kung University Hospital
NOT_YET_RECRUITING

Tainan, 704, Taiwan
New York Cancer and Blood Specialists
RECRUITING

Shirley, New York, 11967, United States
New York Oncology Hematology, P.C.
NOT_YET_RECRUITING

Albany, New York, 12206, United States
Nuovo Ospedale di Prato-S.Stefano
NOT_YET_RECRUITING

Prato, 59100, Italy
Oncology Consultants P.A.
RECRUITING

Houston, Texas, 77030, United States
Onkologisch - Hämatologische Schwerpunktpraxis
NOT_YET_RECRUITING

Bremen, 28209, Germany
Onkologische Schwerpunktpraxis Bielefeld
NOT_YET_RECRUITING

Bielefeld, 33604, Germany
Praxis am Volkspark
NOT_YET_RECRUITING

Berlin, 10715, Germany
Praxisklinik Harburg
NOT_YET_RECRUITING

Hamburg, 21073, Germany
Providence Portland Medical Center
NOT_YET_RECRUITING

Portland, Oregon, 97213, United States
Providence St. Vincent Medical Center
NOT_YET_RECRUITING

Portland, Oregon, 97225, United States
Rotkreuzklinikum München gemeinnützige GmbH
NOT_YET_RECRUITING

München, 80637, Germany
Ruppiner Kliniken
NOT_YET_RECRUITING

Neuruppin, 16816, Germany
St. James's Hospital
NOT_YET_RECRUITING

Dublin, D08 E9P6, Ireland
St. Vincent's University Hospital
NOT_YET_RECRUITING

Dublin, D04 T6F4, Ireland
Taichung Veterans General Hospital
NOT_YET_RECRUITING

Taichung, 407, Taiwan
Tennessee Oncology
RECRUITING

Nashville, Tennessee, 37203, United States
The University of Vermont Medical Center Inc.
NOT_YET_RECRUITING

Burlington, Vermont, 05401, United States
UCLA Hematology/Oncology - Parkside
NOT_YET_RECRUITING

Santa Monica, California, 90404, United States
USC/Norris Comprehensive Cancer Center
NOT_YET_RECRUITING

Los Angeles, California, 90033, United States
UZ Leuven
NOT_YET_RECRUITING

Leuven, 3000, Belgium
Universitaetsklinikum Erlangen
NOT_YET_RECRUITING

Erlangen, 91054, Germany
Universitaetsklinikum Essen
NOT_YET_RECRUITING

Essen, 45147, Germany
Universitaetsklinikum Schleswig-Holstein Campus Kiel
NOT_YET_RECRUITING

Kiel, 24105, Germany
Universitaetsklinikum Tuebingen
NOT_YET_RECRUITING

Tübingen, 72076, Germany
Universitaetsklinikum Ulm
NOT_YET_RECRUITING

Ulm, 89075, Germany
University of Alabama at Birmingham
NOT_YET_RECRUITING

Birmingham, Alabama, 35205, United States
University of Kentucky Chandler Medical Center
NOT_YET_RECRUITING

Lexington, Kentucky, 40536, United States
University of North Carolina Medical Center
NOT_YET_RECRUITING

Chapel Hill, North Carolina, 27514, United States
University of Texas MD Anderson Cancer Center
RECRUITING

Houston, Texas, 77030-4009, United States
University of Virginia Health System
NOT_YET_RECRUITING

Charlottesville, Virginia, 22903, United States
Washington University School of Medicine
NOT_YET_RECRUITING

St Louis, Missouri, 63110, United States
Wilmot Cancer Institute
NOT_YET_RECRUITING

Rochester, New York, 14642, United States
Winship Cancer Institute
NOT_YET_RECRUITING

Atlanta, Georgia, 30322, United States

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