A Study of LY3484356 in Women With Breast Cancer Before Having Surgery

What this trial studies

The purpose for this study is to see if the study drug, LY3484356, is safe and to determine what effects it has on breast cancer in participants with Estrogen Receptor Positive (ER+), HER2 Negative (HER2-) early stage (stage I-III) breast cancer, when given prior to surgery. Participation in this study could last up to 2.5 months.

Conditions in scope

• Breast Cancer

Interventions

• LY3484356 (Drug) — Administered orally.

Who can join

Women only · Ages 18 Years and up

Inclusion criteria

• Have histologically confirmed invasive ER+, HER2- breast carcinoma
• Be willing and able to provide pre- and on-treatment tumor samples
• Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group scale
• Have adequate organ function
• Be able to swallow capsules
• Be a postmenopausal woman

Exclusion criteria

• Have bilateral invasive breast cancer
• Have metastatic breast cancer
• Plan to receive concurrent neoadjuvant therapy with any other non-protocol anti-cancer therapy
• Have had prior therapy (of any kind) for an invasive or non-invasive breast cancer
• Have had prior radiotherapy to the ipsilateral chest wall for any malignancy
• Have had prior anti-estrogen therapy with raloxifene, tamoxifen, aromatase inhibitor, or other selective estrogen receptor modulator (SERM), either for osteoporosis or prevention of breast cancer
• Have had prior hormone-replacement therapy within 4 weeks of the start of study treatment
• Have had major surgery within 28 days prior to randomization to allow for post-operative healing of the surgical wound and site(s)

Eligibility wording paraphrased from the public record. View the full criteria on ClinicalTrials.gov before contacting a site.

Where it’s happening

Showing the first 10 of 19 sites. See all sites on ClinicalTrials.gov.

Status & timeline

• Overall status: Completed
• Study type: Interventional
• Phase: PHASE1
• Start date: 2021-04-21
• Primary completion: 2022-11-11
• Last update posted: 2025-11-12
• First posted: 2020-12-01

Sponsor & contact

Lead sponsor: Eli Lilly and Company (Industry)

For trial site contact information, use the official record at ClinicalTrials.gov. Contact details change frequently and the public record is the source of truth.

Outcome measures

Primary outcomes

• Percent Change From Baseline in Estrogen Receptor (ER) Expression (Baseline, Day 15)
  Tumor tissue collected by biopsy is used to determine ER expression. ER expression is measured by immunohistochemistry (IHC) and quantified by H-score. The H-score was calculated as the sum of multiplying the tumor cell ER staining intensity level 0 to 3 (0=none, 1=low, 2=moderate, 3=high) by the percentage (0 to 100) of cells at each intensity. Total ER H-score ranged…

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