Preember: A Phase 2, Open-Label Study Evaluating Imlunestrant in Premenopausal Women with Estrogen Receptor-Positive, Her2-Negative Breast Cancer

Studying the Effects of an Investigational Medication in Breast Cancer

R
Rina Yadav

Primary Investigator

Recruiting
18 years or above
Female
Phase 2
5 participants needed
2 Locations

Brief description of study

Cohort 1: 
- Assess the effect of imlunestrant versus tamoxifen on tumor cell proliferation (Ki-67). - Assess the effect of imlunestrant versus imlunestrant + goserelin on tumor cell proliferation (Ki-67).

Cohort 2: 
- Assess the rate of symptomatic or complex ovarian cysts with imlunestrant treatment without OFS.

Interested in participating? For more information about this research study or other cancer-related clinical trials at IU Simon Comprehensive Cancer Center, please contact the IU Clinical Trials Office at:
Phone: (317) 278-5632

Detailed description of study

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. 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.

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: Estrogen Receptor-Positive, Her2-Negative Breast Cancer, Breast Neoplasm Female
  • Age: 18 years or above
  • Gender: Female

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 >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 5 years of any adjuvant ET.
  • Be able to swallow capsules or tablets.
  • Be premenopausal women
  • Have adequate organ function.
  • 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.

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
  • 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 presence of ovarian cysts 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.
  • 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.

This study investigates the effects of an investigational medication on premenopausal women with a specific type of breast cancer called estrogen receptor-positive, HER2-negative breast cancer. The purpose of the study is to understand how the investigational medication affects tumor cell growth compared to other treatments. The study is divided into two groups called Cohort 1 and Cohort 2.

In Cohort 1, researchers will compare the effects of the investigational medication alone and in combination with ovarian suppression to another treatment called tamoxifen. In Cohort 2, researchers will observe the effects of the investigational medication on the ovaries without ovarian suppression. Participants will need to provide tumor samples and take capsules or tablets as part of the study procedures.

  • Who can participate: Premenopausal women aged 18 and above with estrogen receptor-positive, HER2-negative breast cancer can participate. Participants must have undergone certain therapies and meet health criteria, including adequate organ function and the ability to swallow capsules or tablets.
  • Study details: Participants will be divided into two cohorts and will need to take capsules or tablets. Cohort 1 will receive the investigational medication with or without ovarian suppression, while Cohort 2 will receive the medication without ovarian suppression. Cohort 1 treatment lasts up to 29 days, and Cohort 2 treatment lasts up to 6 months. Participants in Cohort 1 will also provide tumor samples.
Updated on 09 Apr 2026. Study ID: CTO-J2J-MC-JZLL, 30232

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