Estradiol in Treating Patients With ER Beta Positive, Triple Negative Locally Advanced or Metastatic Breast Cancer
Active, enrolledPhase 2Results postedLast updated 5 March 2026
What this trial tests
Phase 2 trial testing Biopsy in Advanced Triple-Negative Breast Carcinoma in 8 participants. Participants enrolled and being followed up; not accepting new ones.
18 and older, female only, with Advanced Triple-Negative Breast Carcinoma or Anatomic Stage III Breast Cancer AJCC v8. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Clinical Benefit RatePrimary· 173 days
A patient is said to have derived clinical benefit rate at the 6 month time point if the patient's disease meets the Response Evaluation Criteria in Solid Tumors (RECIST) for complete response (CR), partial response (PR), or stable disease (SD) for \> 6 months following initiation of treatment. The 6 month clinical benefit rate is the percentage of patients who are found to meet the criteria for clinical benefit at least 6 months among all the patients who have started estradiol treatment. As the number of patients with discordant ERbeta findings are expected to be small, a 90% exact binomial
Group
Value
95% CI
Treatment (Estradiol)
0
Tumor Response Rate Among Those Patients With Measurable DiseaseSecondary· 173 days
The tumor response rate is defined as the 100% time the number of patients with a CR or PR (as defined by the RECIST criteria) on 2 consecutive evaluations at least 8 weeks apart divided by the total number of eligible patients who began study treatment. A 90% binomial confidence interval is constructed for the true response rate.
Group
Value
95% CI
Treatment (Estradiol)
0
Progression Free Survival (PFS) DistributionSecondary· 173 days
PFS is defined as the time from registration to the first of the following events: local, regional, or distant recurrence, second primary disease of death due to any cause. The distribution of PFS times will be estimated using the method of Kaplan-Meier.
OS is defined as the time from registration to death due to any cause. The distribution of survival times are estimated using the method of Kaplan-Meier.
Group
Value
95% CI
Treatment (Estradiol)
3.8
1 – 17.7
Adverse events — posted to ClinicalTrials.gov
Time frame: Adverse Events followed for 6 months and mortality followed for 18 months.
Reporting threshold: 0%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
This phase II trial studies how well estradiol works in treating patients with estrogen receptor beta (ER beta) positive, triple negative breast cancer that has spread to nearby tissue or lymph nodes (locally advanced) or other places in the body (metastatic). Hormone receptors like ER beta allow the body to respond appropriately to hormones. Triple negative means that the breast cancer does not express other hormone receptors called ER alpha, progesterone, and HER2. In some people with triple negative breast cancer, ER beta is overexpressed. Tumor cells that overexpress ER beta grow slower in the laboratory and this growth is slowed in the presence of estrogen. Estradiol is a form of estrogen. This study may help doctors determine whether tumor cells that overexpress ER beta shrink in the presence of estradiol.
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
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Publications: Europe PMC API search by NCT ID, retrieved 9 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Mayo Clinic
Last refreshed: 5 March 2026
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT03941730.