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Using PET scans and biomarkers to guide treatment for metastatic breast cancer

ECLECTIC: EstroTEP and Circulating Biomarkers to Determine the Optimal Second Line Therapy for ER-positive HER2-negative Metastatic Breast Cancer Patients

Phase 3 Interventional Institut Curie · NCT06195709

This study is testing if using special scans and blood tests can help doctors choose the best treatment for women with a specific type of advanced breast cancer.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment300 (estimated)
Ages18 Years and up
SexAll
SponsorInstitut Curie Academic / other
Drugs / interventionschemotherapy
Locations21 sites (Bayonne and 20 other locations)
Trial IDNCT06195709 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates a strategy for treating ER-positive HER2-negative metastatic breast cancer by utilizing 18F-FES PET/CT scans and circulating tumor biomarkers to determine the most effective treatment approach. Eligible patients will undergo imaging and biomarker assessments to allocate them to either endocrine therapy or chemotherapy based on their individual profiles. The trial aims to improve treatment outcomes by personalizing therapy based on the latest diagnostic tools and biomarkers. Centralized review of imaging and biomarker data ensures unbiased treatment allocation.

Who should consider this trial

Good fit: Ideal candidates are females aged 18 and older with ER-positive HER2-negative metastatic breast cancer who have progressed on first-line endocrine therapy.

Not a fit: Patients with non-metastatic breast cancer or those who have not received prior endocrine therapy may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could lead to more effective and personalized treatment options for patients with metastatic breast cancer.

How similar studies have performed: Other studies utilizing PET imaging and circulating biomarkers have shown promise in personalizing cancer treatment, suggesting a potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Metastatic invasive breast carcinoma of no special type.
2. Females and males of age ≥18 years.
3. Life expectancy \> 3 months.
4. Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2.
5. Estrogen Receptor (ER)-positive (≥10%) and HER2-negative (ASCO/College of American Pathologists guidelines) breast cancer, per local assessment on the most recent breast cancer tissue examined.
6. Tumor block Formalin-Fixed Paraffin-Embedded (primary tumor or metastasis) available.
7. Patients whose disease has progressed on first line endocrine therapy with aromatase inhibitor and CDK4/6 inhibitor and who are deemed eligible, per investigator assessment, to a second line endocrine therapy. The progression on first line endocrine therapy with aromatase inhibitor and CDK4/6 inhibitor must have occurred after more than 6 months on treatment.
8. Patients with available 18F-FDG PET/CT imaging
9. Evaluable disease per RECIST criteria and measurable disease per PERCIST criteria.
10. Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests, and any protocol-related procedures including screening evaluations.
11. Signed informed consent.
12. Patient affiliated to a social security system.

Exclusion criteria:

1. Other breast cancer subtype (e.g. invasive lobular breast carcinoma).
2. One or more prior line of chemotherapy in the metastatic setting.
3. Any other systemic treatment given at metastatic disease than the first line therapy with aromatase inhibitor and CDK4/6 inhibitor.
4. Visceral crisis, per investigator's assessment.
5. Liver-only metastases.
6. Prior exposure to any authorized or experimental agent degrading the estrogen receptor (fulvestrant, oral SERDs, PROTAC, etc).
7. Pregnancy or lactation period.
8. In women of childbearing potential or premenopausal women or women with amenorrhea of less than 12 months, without adequate non-hormonal contraceptive measures (barrier methods, intrauterine contraceptive devices, sterilization; LH-RH agonist cannot be considered as an efficient contraceptive measure), positive urinary or serum pregnancy test 72 hours before 18F-FES PET/CT.
9. Known active uncontrolled or symptomatic Central Nervous System (CNS) metastases, carcinomatous meningitis, or leptomeningeal disease. Patients with a history of CNS metastases or cord compression are eligible if they have been treated with local therapy (e.g., radiotherapy, stereotactic surgery) and are clinically stable and off anticonvulsants and steroids for at least 4 weeks before treatment start.
10. History of previous cancer or hematological malignancy within 3 years preceding patient enrollment in the trial. Multiple primary breast cancers (controlateral/ipsilateral cancers/local relapses) are allowed pending all tumors were ER+ HER2-.
11. Persons deprived of their freedom or under guardianship or incapable of giving consent.

Where this trial is running

Bayonne and 20 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Breast CarcinomaMetastaticPET/CT 18F-FESCirculating markers
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.