Metastatic Breast Cancer (HR+/ HER2-)NCT07867925
Predicting Endocrine Resistance Using Molecular Imaging and Liquid Biopsy in Metastatic Breast Cancer
An observational study of Metastatic Breast Cancer (HR+/ HER2-), run by Asan Medical Center at 1 site in South Korea.
Trial summary
This prospective observational study aims to evaluate the prognostic value of molecular imaging biomarkers derived from baseline [18F]FES and [18F]FDG PET/CT for progression-free survival in patients with estrogen receptor (ER)-positive, HER2-negative metastatic breast cancer receiving first-line endocrine therapy… Read more about this study
- Who is it for?
- Ages 19 years and older
- Conditions the study is for
- Metastatic Breast Cancer (HR+/ HER2-)
- What is being tested?
- [18F] FES
- Type of treatment
- Injection or infusion
- How many people
- 100 participants
- Where
- 1 siteSouth Korea
- Study dates
- 13 Oct 2026to 31 Dec 2030
- Phase
- Observational
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Patients with ER-positive, HER2-negative metastatic breast cancer who are scheduled to initiate first-line endocrine therapy with an aromatase inhibitor in combination with a CDK4/6 inhibitor at Asan Medical Center. Potentially eligible patients will be identified from the medical oncology outpatient clinic or inpatient wards and prospectively enrolled according to the predefined eligibility criteria.
Who may be able to join
- Male or female participants aged 19 years or older, regardless of race or ethnicity.
- Histologically confirmed invasive breast cancer that is ER-positive and HER2-negative by immunohistochemistry.
- Scheduled to initiate first-line systemic endocrine therapy with an aromatase inhibitor in combination with a CDK4/6 inhibitor for metastatic breast cancer within 60 days of screening.
- Have undergone or be scheduled to undergo [18F]FDG PET/CT before initiation of endocrine therapy combined with a CDK4/6 inhibitor.
- Have measurable or clinically evaluable metastatic disease on standard-of-care imaging.
- Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
Who cannot join
- Failure of the participant or the participant's legally authorized representative to provide written informed consent.
- History of another invasive malignancy within the previous 2 years, except for non-melanoma skin cancer.
- Absence of lesions with significant uptake on [18F]FDG PET/CT, or inability to quantitatively evaluate major lesions because of lesion location (e.g., brain or other sites with high physiologic uptake), severe motion artifacts, reconstruction errors, or other technical limitations.
- Metastatic disease confined exclusively to the liver on imaging.
- Previous systemic treatment for metastatic breast cancer, including endocrine therapy, targeted therapy, or anticancer chemotherapy including antibody-drug conjugates (ADCs).
- Pregnancy or breastfeeding. Participants are considered not to be of childbearing potential if they are physiologically postmenopausal (amenorrhea for at least 2 years) or surgically sterile (documented bilateral oophorectomy or hysterectomy). Participants of childbearing potential must have a negative serum or urine pregnancy test within 24 hours before [18F]FES administration and must use contraception during the study period.
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- Serious, uncontrolled, and/or unstable medical conditions, including but not limited to congestive heart failure, acute myocardial infarction, severe pulmonary disease, chronic kidney disease, or chronic liver disease.
- Being a relative or student of an investigator or otherwise having a dependent relationship with an investigator.
- Any personal circumstances or other conditions that, in the investigator's judgment, are likely to prevent complete collection of study data.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
South Korea1 site
Asan Medical Center
Seoul
Sangwon Han, +82-2-3010-0657, hswon87@amc.seoul.kr
About this study
Official title: PREDICTion of Endocrine Resistance Using Molecular Imaging and Liquid Biopsy in Metastatic Breast Cancer (PREDICT-ER)
This prospective observational study aims to evaluate the prognostic value of molecular imaging biomarkers derived from baseline [18F]FES and [18F]FDG PET/CT for progression-free survival in patients with estrogen receptor (ER)-positive, HER2-negative metastatic breast cancer receiving first-line endocrine therapy combined with a CDK4/6 inhibitor. In a subset of patients with available tumor tissue, paired tumor tissue next-generation sequencing (NGS) and circulating tumor DNA (ctDNA) analysis will also be performed to investigate their associations with imaging biomarkers, treatment response, and clinical outcomes.
Read the detailed description
Endocrine therapy combined with CDK4/6 inhibitors is a standard first-line treatment for patients with ER-positive, HER2-negative metastatic breast cancer. However, treatment response varies among patients, and both de novo and acquired endocrine resistance remain major causes of disease progression. Changes in ER expression and molecular alterations such as ESR1 mutations and alterations in the PI3K-AKT pathway have been implicated in the development of endocrine resistance.
[18F]FES PET/CT enables noninvasive whole-body assessment of ER expression in lesions, and may provide information on spatial heterogeneity of ER expression across metastatic lesions. In combination with [18F]FDG PET/CT, which reflects tumor glucose metabolism, molecular imaging may provide complementary information regarding tumor biology and treatment resistance. Imaging biomarkers reflecting inter-lesional heterogeneity in FES uptake and quantitative FDG metabolic activity may therefore be useful for predicting outcomes during endocrine therapy.
Circulating tumor DNA (ctDNA) provides a minimally invasive method for detecting tumor-derived genomic alterations, including mutations associated with endocrine resistance. Integrating ctDNA and tumor tissue genomic findings with molecular imaging may provide a more comprehensive assessment of the molecular and spatial heterogeneity of metastatic breast cancer.
This single-center, prospective observational cohort study will enroll patients with ER-positive, HER2-negative metastatic breast cancer who are scheduled to receive first-line endocrine therapy with an aromatase inhibitor combined with a CDK4/6 inhibitor. Baseline molecular imaging biomarkers will be derived from [18F]FES and [18F]FDG PET/CT. The primary objective is to evaluate the prognostic value of these imaging biomarkers for progression-free survival during first-line endocrine therapy combined with a CDK4/6 inhibitor.
In a subset of participants with adequate tumor tissue available, paired ctDNA analysis and tumor tissue next-generation sequencing will also be performed to investigate their associations with progression-free survival and molecular imaging biomarkers. Changes in [18F]FDG PET/CT findings during treatment and molecular and imaging characteristics associated with disease progression will also be explored.
- Conditions
- Metastatic Breast Cancer (HR+/ HER2-)
- Being tested
- [18F] FES
- Keywords
- breast cancer, [18F]FES PET/CT, [18F]FDG PET/CT, Endocrine therapy, Endocrine resistance, ctDNA
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
[18F] FESDiagnostic test
Participants will undergo baseline 18F-fluoroestradiol ([18F]FES) PET/CT before initiation of first-line endocrine therapy combined with a CDK4/6 inhibitor. [18F]FES (111-222 MBq) will be administered intravenously, and whole-body PET/CT imaging will be performed according to the institutional imaging protocol. [18F]FES PET/CT will be used to assess estrogen receptor expression and heterogeneity across metastatic lesions.
| Study group | Role | What they receive |
|---|---|---|
| ER-Positive, HER2-Negative Metastatic Breast Cancer | Participants with ER-positive, HER2-negative metastatic breast cancer who are scheduled to receive first-line endocrine therapy with an aromatase inhibitor in combination with a CDK4/6 inhibitor. Receives: Diagnostic Test: [18F] FES |
What is being measured
The primary outcome is the main question the study is designed to answer.
Prognostic value of baseline [18F]FES and [18F]FDG PET/CT-derived molecular imaging biomarkers for progression-free survival
Association of baseline molecular imaging biomarkers derived from [18F]FES and [18F]FDG PET/CT with progression-free survival (PFS) during first-line endocrine therapy combined with a CDK4/6 inhibitor
Measured: From initiation of first-line endocrine therapy until the date of first documented disease progression or death from any cause, whichever occurs first, assessed up to 48 months.
Secondary outcomes (4)
Prognostic value of baseline ctDNA-based liquid biopsy biomarkers for progression-free survival
Association of baseline ctDNA-based liquid biopsy biomarkers with progression-free survival during first-line endocrine therapy combined with a CDK4/6 inhibitor
Measured: From initiation of first-line endocrine therapy until the date of first documented disease progression or death from any cause, whichever occurs first, assessed up to 48 months.
Prognostic value of baseline tumor tissue NGS findings for progression-free survival
Association of baseline tumor tissue NGS findings with progression-free survival during first-line endocrine therapy combined with a CDK4/6 inhibitor
Measured: From initiation of first-line endocrine therapy until the date of first documented disease progression or death from any cause, whichever occurs first, assessed up to 48 months.
Prognostic value of changes in ctDNA-based liquid biopsy biomarkers at 12 weeks for progression-free survival
Association of changes in ctDNA-based liquid biopsy biomarkers from baseline to approximately 12 weeks after treatment initiation with progression-free survival during first-line endocrine therapy combined with a CDK4/6 inhibitor.
Measured: From 12 weeks after treatment initiation until the date of first documented disease progression or death from any cause, whichever occurs first, assessed up to 48 months after treatment initiation.
Association among baseline molecular imaging biomarkers, ctDNA-based liquid biopsy biomarkers, and tumor tissue NGS findings
Association among molecular imaging biomarkers derived from baseline [18F]FES and [18F]FDG PET/CT, baseline ctDNA-based liquid biopsy biomarkers, and tumor tissue NGS findings
Measured: At baseline, before initiation of first-line endocrine therapy.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Oct 2026
- Study start13 Oct 2026 (estimated)
- Primary completion31 Dec 2030 (estimated)
- Study completion31 Dec 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Metastatic Breast Cancer (HR+/ HER2-)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Asan Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Sangwon Han, Asan Medical Center
- Investigators
- Sangwon Han, Clinical assistant professor, Principal investigator, Asan Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07867925
- Sponsor's protocol ID
- PREDICT-ER
- Status last verified
- Oct 2026
- First submitted
- 19 Aug 2026
- Last updated
- 9 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No