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ClinicalTrials.gov 6 recruiting now early-phase tilt small index

Estrogen Receptor-positive Breast Cancer: early-phase trial registry

6 of 17 indexed Estrogen Receptor-positive Breast Cancer trials are currently recruiting, with more weight in Phase 1-2.

Corpus placement: #1,004 of 28,707 conditions by registered trial count.

17 US clinical trials · 6 currently recruiting · #1,004 of 28,707 conditions by registered trial count

Estrogen Receptor-positive Breast Cancer: 17 US clinical trials tracked, 6 recruiting.

Estrogen Receptor-positive Breast Cancer is the subject of 17 registered US clinical trials on ClinicalTrials.gov, 6 of them currently open to new participants. 2 are in Phase 3-4 (later-stage) and 8 in Phase 1-2 (earlier-stage). The most active sponsor is University of Pittsburgh Medical Center, running 1 of these trials.

Enrollment posture brief

Registry condition estrogen-receptor-positive-breast-cancer

OPEN 6 | RECR 35% | LATE 2 | EARLY 8 | RANK #1004 | SPON 1

Nearest open-share peer: Arrhythmia (35% recruiting · 17 trials)

Acute Myeloid Leukemia, in R70.6%Abdominal Aortic Aneurysm52.9%Estrogen Receptor-positi (th…35%Acute Lymphoblastic Leukemia23.5%Actinic Keratosis11.8%
Open-enrollment share among volume-matched conditions near Estrogen Receptor-positive Breast Cancer

Estrogen Receptor-positive Breast Cancer lists 6 open slots (35% of 17 indexed trials). Peers are matched on registered volume, not therapeutic-area browse lists. How peer matching works →

Key findings

What ClinicalTrials.gov does not surface for Estrogen Receptor-positive Breast Cancer on its own pages , computed from the registry mirror as of 2026-08-08. Each line carries its own denominator so it can be quoted as it stands.

  1. Estrogen Receptor-positive Breast Cancer is recruiting below its size-band peers.

    6 of 17 indexed trials (35.3%) are open to enrollment, against a 46.5% average across 27,806 conditions with fewer than 20 trials. The peer set uses the same ClinicalTrials.gov-derived counts as this page.

  2. Sponsorship of Estrogen Receptor-positive Breast Cancer trials is spread across many organizations.

    University of Pittsburgh Medical Center accounts for 1 of 17 trials (5.9%). 17 distinct sponsors appear on at least one study for this condition label.

  3. Most Estrogen Receptor-positive Breast Cancer trials plan to enrol fewer than 100 people.

    Median target enrolment is 72 among the 17 trials that report a genuine target (sentinel values excluded). 11 of those (64.7%) plan for fewer than 100 participants.

  4. Estrogen Receptor-positive Breast Cancer research is mostly interventional.

    14 interventional and 3 observational studies make up this index (82.4% interventional). Study type is sponsor-reported on ClinicalTrials.gov.

Phase 11Phase 27Phase 32

Open and recent trials

17 total, page 1 of 1

RECRUITING Phase 2 297 participants

PhII Randomized CAPecitabine + ELAcestrant vs. Capecitabine Alone in ER+ Breast Cancer (CAPELA)

Kristina A. Fanucci

NCT07222215

RECRUITING Phase 2 174 participants

Elacestrant vs Elacestrant Plus a CDK4/6 Inhibitor in Patients With ERpositive/HER2-negative Advanced or Metastatic Breast Cancer

Northwestern University

NCT06062498

RECRUITING NA 114 participants

Breast Re-irradiation After Second Ipsilateral Lumpectomy

Youssef Zeidan

NCT06867484

RECRUITING Phase 2 87 participants

(Z)-Endoxifen for the Treatment of Premenopausal Women With ER+/HER2- Breast Cancer

Atossa Therapeutics

NCT05607004

RECRUITING Phase 2 72 participants

The SAPPHO Study: Sequential Therapy With Curative Intent in de Novo HER2+ Metastatic Breast Cancer

Dana-Farber Cancer Institute

NCT06439693

RECRUITING Phase 2 35 participants

Adaptive Therapy With Capecitabine for Treatment of Metastatic ER Positive, HER2 Negative Breast Cancer

Mayo Clinic

NCT06525766

ACTIVE NOT RECRUITING Phase 3 1,473 participants

Fulvestrant and/or Anastrozole in Treating Postmenopausal Patients With Stage II-III Breast Cancer Undergoing Surgery

Alliance for Clinical Trials in Oncology

NCT01953588

ACTIVE NOT RECRUITING NA 1,046 participants

A Study to Evaluate Genetic Predictors of Aromatase Inhibitor Musculoskeletal Symptoms (AIMSS)

ECOG-ACRIN Cancer Research Group

NCT01824836

ACTIVE NOT RECRUITING Phase 3 518 participants

Randomized, Open Label, Clinical Study of the Targeted Therapy, Palbociclib, to Treat Metastatic Breast Cancer

Alliance Foundation Trials

NCT02947685

ACTIVE NOT RECRUITING 75 participants

FDG PET/CT in Breast Cancer Bone Mets

University of Pennsylvania

NCT01996046

ACTIVE NOT RECRUITING Phase 1 46 participants

BYL719 and Letrozole in Post-Menopausal Patients With Hormone Receptor-Positive Metastatic Breast Cancer

Vanderbilt-Ingram Cancer Center

NCT01791478

ACTIVE NOT RECRUITING Phase 2 46 participants

Neoadjuvant Pembrolizumab + Decitabine Followed by Std Neoadj Chemo for Locally Advanced HER2- Breast Ca

Virginia Commonwealth University

NCT02957968

ACTIVE NOT RECRUITING Phase 2 33 participants

REVIVE: Replens Versus Intra-Vaginal Estrogen for the Treatment of Vaginal Dryness on Aromatase Inhibitor Therapy

Polly A. Niravath, MD

NCT01984138

COMPLETED 68 participants

Evaluation of Endocrine Therapy Effects of Host Immunity in Early Stage Breast Cancer

Duke University

NCT03719495

COMPLETED NA 50 participants

Exercise Intervention in Preventing Breast Cancer Recurrence in Postmenopausal Breast Cancer Survivors

City of Hope Medical Center

NCT02235051

COMPLETED NA 13 participants

Pilot Study Estradiol Followed by Exemestane Hormone Receptor + Metastatic Breast Cancer

University of Arizona

NCT01385280

COMPLETED 7 participants

Electronic Medical Record-Based Nudge to Reduce SLNB

University of Pittsburgh Medical Center

NCT06006910

Phase Distribution

PhaseTrial count
Phase 1 1
Phase 2 7
Phase 3 2

Named interventions

Most-linked intervention names on Estrogen Receptor-positive Breast Cancer records (sponsor-reported on ClinicalTrials.gov). Counts are trial links, not unique products.

laboratory biomarker analysis Other
3 trials
anastrozole Drug
2 trials
letrozole Drug
2 trials
Paclitaxel Drug
2 trials
Capecitabine Drug
2 trials
enzyme-linked immunosorbent assay Other
1 trials
No column-based nudge in the EHR Behavioral
1 trials
Column-based nudge in the EHR Behavioral
1 trials

US sites by state

Facility locations filed on Estrogen Receptor-positive Breast Cancer trials. A trial with sites in several states counts in each.

Massachusetts 5 trials
Arizona 4 trials
Illinois 3 trials
Florida 3 trials
California 3 trials
Virginia 2 trials
Texas 2 trials
Tennessee 2 trials

Source: ClinicalTrials.gov, National Library of Medicine. Data is informational only.

What to do with this Estrogen Receptor-positive Breast Cancer page

17 registered trials, 6 currently recruiting, is a starting point for a conversation, not a diagnosis or a recommendation.

Trial and recruiting counts reflect ClinicalTrials.gov registry status as of the data vintage above; individual trial eligibility and enrollment status can change.

Every figure on PlainTrial is rendered directly from the ClinicalTrials.gov registry, no number is typed in by an editor. This Estrogen Receptor-positive Breast Cancer condition card totals 17 registered trials; most-linked intervention laboratory biomarker analysis; top US site state Massachusetts. See our editorial standards & corrections policy, the methodology behind these numbers, the data changelog, or report a data error.