NCT05716516 · Dartmouth-Hitchcock Medical Center
STUDY02001740;22SCH740: Estradiol For ER+ Advanced Breast Cancer (ESTHER)
(ESTHER)
What this study is about
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
View original scientific description
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
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Post-menopausal women with ER+ breast cancer.
- Metastatic or locoregional recurrence not amenable to treatment with curative
- 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.
- Acute myocardial infarction.
- Congestive heart failure.
- Previous malignancy not treated with curative intent, or with an estimated recurrence risk ≥30%.
Where
- Lebanon, New Hampshire
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 5, 2026 · Source of record for eligibility and locations