Clinical trial · Interventional
STUDY02001740;22SCH740: Estradiol For ER+ Advanced Breast Cancer (ESTHER)
Phase II Study of Estradiol Therapy to Target ER-Mutant and ER-Wild-Type ER+ Metastatic or Advanced Breast Cancer
NCT05716516CI-TRIAL-00110497ESTHERrecruitingPhase 2ClinicalTrials.gov clinicaltrialsProvenance
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
Determine whether subjects harboring ESR1-mutant/amplified breast cancer have a higher rate of clinical benefit from 17b-estradiol therapy than subjects with ESR1-wild-type breast cancer
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Metastatic Breast Cancer | Malignant Breast Neoplasm | CURATED_BROADER | 0.78 |
Interventions
Interventions (1)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Estradiol | Drug | — | UNRESOLVED |
Design
Arms and outcomes
Arms (1)
- type
- OTHER
- label
- Treatment Arm
- description
- Treatment Phase: Patients will be treated with 17b-estradiol until disease progression. At this point, the patient will end protocol therapy
- interventionNames
- Drug: Estradiol
Primary outcomes (1)
- measure
- Clinical Benefit Rate
- timeFrame
- 12 months
- description
- The clinical benefit rate (complete responses + partial responses + stable disease at 24 weeks) will be ascertained and compared between subjects treated with 17b-estradiol harboring amplified/mutant ESR1 and wild-type ESR1.
Secondary outcomes (4)
- measure
- Objective response rate
- timeFrame
Eligibility
Eligibility (as posted)
- Sex
- Female
- Minimum age
- 18 Years
Show eligibility criteria text
Inclusion Criteria: * Post-menopausal women with ER+ breast cancer. * Metastatic or locoregional recurrence not amenable to treatment with curative * intent. * Received ≥1 prior line of endocrine-based therapy (e.g., including tamoxifen, aromatase inhibitors, fulvestrant, or combinations) in the advanced/metastatic setting Exclusion Criteria: * During the study Treatment Phase with 17b-estradiol, no concurrent anti-cancer therapies are allowed with the following exceptions: * Exception: Trastuzumab is allowed for the treatment of subjects with a history of HER2+ disease, and will be used at the physician's discretion. * Exception: Anti-resorptive bone therapies (e.g., bisphosphonates, denosumab) are permitted. * Any investigational cancer therapy in the last 3 weeks. * Known CNS disease, unless clinically stable for ≥ 3 months. * History of any of the following: * Deep venous thrombosis. * Pulmonary embolism. * Stroke. * Acute myocardial infarction. * Congestive heart failure. * Previous malignancy not treated with curative intent, or with an estimated recurrence risk ≥30%.
References
Publications (0)
Data not yet available
No reference posted for this study.