ER Positive Breast Cancer Clinical Trials

12 recruitingLast updated: June 17, 2026

There are 12 actively recruiting er positive breast cancer clinical trials across 31 countries. Studies span Phase 2, Phase 3, Phase 1. Top locations include Houston, Texas, United States, Genova, Italy, Alicante, Spain. Updated daily from ClinicalTrials.gov.


ER Positive Breast Cancer Trials at a Glance

12 actively recruiting trials for er positive breast cancer are listed on ClinicalTrialsFinder across 6 cities in 31 countries. The largest study group is Phase 2 with 4 trials, with the heaviest enrollment activity in Houston, Genova, and Alicante. Lead sponsors running er positive breast cancer studies include Olema Pharmaceuticals, Inc., Fondazione Sandro Pitigliani, and European Organisation for Research and Treatment of Cancer - EORTC.

Browse er positive breast cancer trials by phase

Treatments under study

About ER Positive Breast Cancer Clinical Trials

Looking for clinical trials for ER Positive Breast Cancer? There are currently 12 studies actively recruiting participants. Clinical trials offer access to new treatments before they are widely available, and every approved therapy in use today was first tested through a clinical trial.

Below you can browse trials, sign up for alerts when new ER Positive Breast Cancer trials open, and view eligibility criteria for each study. Each listing includes the study phase, locations, and enrollment details.

Frequently Asked Questions

Common questions about ER Positive Breast Cancer clinical trials

A clinical trial is a carefully designed research study that tests new medical treatments, drugs, devices, or approaches in human volunteers. Every approved medication and treatment available today was proven safe and effective through clinical trials.

All clinical trials are reviewed and approved by Institutional Review Boards (IRBs) — independent committees that evaluate patient safety. Trials follow strict protocols, and your health is monitored closely throughout. You can withdraw at any time.

Not necessarily. Many trials compare the new treatment against the current standard of care, meaning all participants receive active treatment. When placebos are used, they are typically combined with standard treatment, not given alone. The trial description will always specify the design.

Under the Affordable Care Act, most private insurers are required to cover routine patient care costs during a clinical trial. The sponsor typically covers the investigational treatment itself. Medicare also covers routine costs for qualifying trials.

Yes. Participation is completely voluntary. You can withdraw at any time, for any reason, without it affecting your access to standard medical care.

Each trial has specific eligibility criteria — including age, diagnosis, disease stage, prior treatments, and general health. Browse the trials listed above and check their eligibility sections. You can also contact the trial site directly to discuss your situation.

Showing 112 of 12 trials

Recruiting
Phase 3

Palazestrant in Combination With Ribociclib for the First-line Treatment of ER+/HER2- Advanced Breast Cancer

Breast CancerMetastatic Breast CancerHER2-Negative Breast Carcinoma+2 more
Olema Pharmaceuticals, Inc.1,000 enrolled150 locationsNCT07085767
Recruiting
Phase 3

Elacestrant for Treating ER+/HER2- Breast Cancer Patients With ctDNA Relapse (TREAT ctDNA)

HER2-negative Breast CancerER Positive Breast CancerStage III Breast Cancer+1 more
European Organisation for Research and Treatment of Cancer - EORTC220 enrolled109 locationsNCT05512364
Recruiting
Phase 2

Trial of Pre-operative Neratinib and Endocrine Therapy With Trastuzumab in ER-Positive, HER-2 Positive Breast Cancers

Breast CancerER Positive Breast CancerHER2-positive Breast Cancer+1 more
Ruth O'Regan30 enrolled4 locationsNCT04886531
Recruiting
Phase 3

Elacestrant + Everolimus in Patients ER+/HER2-, ESR1mut, Advanced Breast Cancer Progressing to ET and CDK4/6i.

HER2-negative Breast CancerAdvanced Breast CancerER Positive Breast Cancer+1 more
MedSIR240 enrolled99 locationsNCT06382948
Recruiting
Phase 3

OP-1250 (Palazestrant) vs. Standard of Care for the Treatment of ER+/HER2- Advanced Breast Cancer

Breast CancerMetastatic Breast CancerHER2-Negative Breast Carcinoma+2 more
Olema Pharmaceuticals, Inc.510 enrolled233 locationsNCT06016738
Recruiting
Phase 2

Fulvestrant+Abemaciclib With Run-In of Fulvestrant in Er-Positive, Her2-Negative Metastatic Breast Cancer

HER2-negative Breast CancerER Positive Breast Cancer
The Methodist Hospital Research Institute28 enrolled1 locationNCT05305924
Recruiting
Phase 1

Phase 1b Study of OP-1250 (Palazestrant) in Combination With Ribociclib, Alpelisib, Everolimus, or Atirmociclib in ER+, HER2- Breast Cancer

Breast CancerMetastatic Breast CancerHER2-negative Breast Cancer+2 more
Olema Pharmaceuticals, Inc.190 enrolled16 locationsNCT05508906
Recruiting
Phase 2

DATO-BASE: DATOpotamab-deruxtecan for Breast Cancer Brain metAstaSEs

Breast CancerBreast Cancer FemaleHER2-Negative Breast Carcinoma+4 more
Sarah Sammons, MD58 enrolled3 locationsNCT06176261
Recruiting

Role of the Immune Environment in Response to Therapy in Breast Cancer

Breast CancerHER2-negative Breast CancerER Positive Breast Cancer+1 more
Abramson Cancer Center at Penn Medicine300 enrolled1 locationNCT05396612
Recruiting
Phase 1

PRE-I-SPY Phase I/Ib Oncology Platform Program

Triple-Negative Breast CancerMetastatic Breast CancerHER2-low Breast Cancer+18 more
QuantumLeap Healthcare Collaborative124 enrolled7 locationsNCT05868226
Recruiting

To Identify Primary Resistance to CDK4/6 Inhibitors in Breast Cancer

Metastatic Breast CancerHER2-negative Breast CancerER Positive Breast Cancer
Fondazione Sandro Pitigliani150 enrolled1 locationNCT04660435
Recruiting
Phase 2

Immunotherapy, Hormone Therapy, and AKT Inhibitor for Premenopausal ER Positive MBC

Metastatic Breast CancerER Positive Breast CancerPremenopausal Breast Cancer
National Taiwan University Hospital42 enrolled1 locationNCT05720260