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ClinicalTrials.gov 6 recruiting now official registry

Estrogen Receptor-positive Breast Cancer clinical trials

6 of 17 indexed Estrogen Receptor-positive Breast Cancer trials are currently recruiting.

17 US clinical trials · 6 currently 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.

The research picture

Estrogen Receptor-positive Breast Cancer has 17 registered US clinical trials, 6 of them open to new participants right now, about 35% of the total.

6
recruiting participants now
35%
of trials open to enrollment
2
in Phase 3–4 (later-stage)
1
top sponsor: University of Pittsburgh Medical Center
Phase 11Phase 27Phase 32

Active & 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

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

Reading the Estrogen Receptor-positive Breast Cancer Trial Landscape

17 indexed Estrogen Receptor-positive Breast Cancer studies · 6 recruiting (35%).

Phase mix: 2 late (III/IV) vs 8 early (I/II).

Top sponsor: University of Pittsburgh Medical Center (1 trial), 9 others listed. 17 shown below, recruiting first.

How to read this condition's trial landscape

That ratio is a useful proxy for activity level: a high share of recruiting studies often signals that research interest is current and that new enrollment opportunities are appearing, while a low share typically means the field is dominated by completed or follow-up work where most participant spots have already been filled. These counts reflect the public registry only and include studies at every stage of design, so they should be read as an index of research attention rather than as a measure of treatment availability.

Phase 1 and Phase 2 studies focus on early safety signals, dosing, and preliminary effect, while Phase 3 studies are typically the larger efficacy and safety trials submitted toward regulatory review, and Phase 4 studies follow approved interventions in real-world use. A condition weighted toward later phases often reflects a mature research pipeline with several interventions already close to or past approval, whereas a heavier early-phase tilt suggests the field is still exploring new mechanisms and candidate approaches.

All figures are derived from the public ClinicalTrials.gov dataset maintained by the National Library of Medicine and are reproduced here for reference. Inclusion of a trial, sponsor, or intervention on this page is neither an endorsement nor a recommendation, eligibility, protocol changes, and site-level status can shift frequently, so always verify current details on ClinicalTrials.gov and consult a qualified healthcare provider before acting on anything you see here.

Frequently Asked Questions

How many clinical trials are there for Estrogen Receptor-positive Breast Cancer?

PlainTrial tracks 17 US clinical trials for Estrogen Receptor-positive Breast Cancer, of which 6 are currently recruiting participants. Data sourced from ClinicalTrials.gov.

How do I find a recruiting trial for Estrogen Receptor-positive Breast Cancer?

Use the trial list above filtered by "Recruiting" status, or visit our trial finder at /recruiting to search by condition and state. Always discuss trial participation with your healthcare provider before enrolling.

Is this data current?

Data is sourced from ClinicalTrials.gov and reflects our most recent data pull. Trial status may have changed since then. Always verify current information at ClinicalTrials.gov before making decisions about participation.

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from ClinicalTrials.gov (National Library of Medicine). Consult a qualified professional before making decisions based on this data.

Source: ClinicalTrials.gov (NIH/NLM) ClinicalTrials.gov AACT registry · 2026 Trial counts and statuses sourced from ClinicalTrials.gov. Sponsor counts include both industry and federal/academic sponsors.

Verify with NIH →

Every figure on PlainTrial is rendered directly from the ClinicalTrials.gov registry, no number is typed in by an editor. This page aggregates every registered trial for this condition, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.