for people ages 18 years and up (full criteria)
at Berkeley, California and other locations
study started
completion around
Principal Investigator
by Hope S Rugo
Headshot of Hope S Rugo
Hope S Rugo



The main purpose of this study is to measure how well imlunestrant works compared to standard hormone therapy in participants with early breast cancer that is estrogen receptor positive (ER+) and human epidermal receptor 2 negative (HER2-). Participants must have already taken endocrine therapy for two to five years and must have a higher-than-average risk for their cancer to return. Study participation could last up to 10 years.

Official Title

EMBER-4: A Randomized, Open-Label, Phase 3 Study of Adjuvant Imlunestrant vs Standard Adjuvant Endocrine Therapy in Patients Who Have Previously Received 2 to 5 Years of Adjuvant Endocrine Therapy for ER+, HER2- Early Breast Cancer With an Increased Risk of Recurrence


Breast Neoplasms, Tamoxifen, Letrozole, Anastrozole, Exemestane, Imlunestrant


You can join if…

Open to people ages 18 years and up

  • Have a diagnosis of ER+, HER2- early-stage, resected, invasive breast cancer without evidence of distant metastasis.
  • Participants must have received at least 24 months but not more than 60 months of any adjuvant ET, from time of adjuvant ET initiation.
  • Participants may have received (neo) adjuvant chemotherapy and/or targeted therapy with a CDK4/6- or PARP- inhibitor.
  • Must have an increased risk of disease recurrence based on clinical-pathological risk features.
  • Have a Performance Status of 0 or 1 on the Eastern Cooperative Oncology Group scale.
  • Have adequate organ function.

You CAN'T join if...

  • Have any evidence of metastatic disease (including contralateral ALN) or inflammatory breast cancer at primary breast cancer diagnosis.
  • Participants with more than a 6-month consecutive gap in therapy during the course of prior adjuvant ET.
  • Participants who have completed or discontinued prior adjuvant ET >6 months prior to screening.
  • Participants with a history of previous breast cancer are excluded, with the exception of ipsilateral DCIS treated by locoregional therapy alone ≥5 years ago.
  • Pregnant, breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the screening visit through 180 days after the last dose of study intervention.
  • Participant has previously received ET of any duration for breast cancer prevention (tamoxifen or AIs) or raloxifene.
  • Participants with a history of any other cancer.
  • Have serious preexisting medical conditions that, in the judgment of the investigator, would preclude participation in this study.


  • UCSF - John Muir Health Cancer Center Berkeley accepting new patients
    Berkeley California 94702 United States
  • Zuckerberg San Francisco General Hospital and Trauma Center accepting new patients
    San Francisco California 94110 United States
  • UCSF Medical Center at Mission Bay accepting new patients
    San Francisco California 94158 United States

Lead Scientist at UCSF

  • Hope S Rugo
    Dr. Hope Rugo is a medical oncologist and hematologist specializing in breast cancer research and treatment. A Clinical Professor of Medicine, Dr. Rugo joined the Breast Care Center in 1999 after a decade of experience at UCSF in malignant hematology and bone marrow transplantation for a variety of diseases, including breast cancer.


accepting new patients
Start Date
Completion Date
Eli Lilly and Company
A Study of Imlunestrant Versus Standard Endocrine Therapy in Participants With Early Breast Cancer (EMBER-4)
Phase 3 research study
Study Type
Expecting 6000 study participants
Last Updated