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.
Conditions: Breast Neoplasms
Eligibility Criteria
Inclusion Criteria
- 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.
Exclusion Criteria
- 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.
Eligibility criteria are kept as the original English records from ClinicalTrials.gov; actual eligibility is determined by the research team's formal assessment and the informed consent form. Source: ClinicalTrials.gov, updated automatically every two weeks. Last synced: 2026年10月8日.