Breast CancerPhase 2NCT06335069
18F-FDG Versus 68Ga-FAPI-46 as PET Tracer in ER-positive Breast Cancer.
A Phase 2 study testing 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI in people with Breast Cancer and Breast Neoplasms, run by Maastricht University Medical Center at 1 site in Netherlands.
Trial summary
The extent of breast cancer is an important prognostic factor in patients diagnosed with this disease. Therefore, adequate staging at diagnosis is a requisite for optimal treatment. In all patients diagnosed with locally advanced breast cancer (LABC), distant staging using 18F-FDG PET/CT is recommended. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Breast Cancer, Breast Neoplasms, Breast Diseases
- What is being tested?
- 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteNetherlands
- Study dates
- 1 Sep 2025to Mar 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
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 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Female patient with histopathologically proven ER+ breast cancer.
- Diagnosed with locally advanced (primary tumor >5 cm and/or presence of axillary lymph node metastases) or recurrent breast cancer, or metastatic breast cancer for which 18F-FDG PET/CT or 18F-FDG PET/MRI staging is performed.
- Willing and able to undergo the study procedures.
- Has personally provided written informed consent.
Who cannot join
- Age <18
- Pregnancy
- Patients with secondary malignancies (except non-melanoma skin cancer)
- No 18F-FDG PET/CT or 18F-FDG PET/MRI scan.
- Contra-indications for PET/MRI such as pacemaker, aneurysm clips, metallic device in their body, severe claustrophobia, and severe obesity
- Chronic inflammatory disease such as rheumatoid arthritis.
- Patients with severe hepatic or renal impairment (eGFR ≤45mL/min/1.73m²)
- Inability to provide informed consent.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Netherlands1 site, 1 recruiting
- Recruiting
Maastricht University Medical Center+
Maastricht, 5800
Thiemo JA van Nijnatten, MD, PhD, thiemo.nijnatten@mumc.nl
About this study
Official title: 18F-FDG Versus 68Ga-FAPI-46 as PET Tracer in ER-positive Breast Cancer - a Pilot Study.
The extent of breast cancer is an important prognostic factor in patients diagnosed with this disease. Therefore, adequate staging at diagnosis is a requisite for optimal treatment. In all patients diagnosed with locally advanced breast cancer (LABC), distant staging using 18F-FDG PET/CT is recommended. However, the degree of metabolic uptake in the primary breast tumor is significantly lower in the ER+ subtype compared to HER2+ and triple negative breast cancer (TNBC). As a consequence, a suboptimal 18F-FDG uptake in ER+ breast cancer patients can potentially lead to missed distant metastases. Fibroblast-activating protein inhibitor (FAPI) is a recently developed radiotracer that binds to FAP, a stromal antigen overexpressed in more than 90% of epithelial-derived tumors and their metastases. Previous studies all show 68Ga-FAPI PET/CT to have a higher detection rate compared to 18F-FDG PET/CT. However, all previous studies were performed without considering breast cancer subtype. If the metabolic uptake by 68Ga-FAPI-46 is higher in ER+ breast cancer patients, more lesions will be detected, resulting in a more appropriate treatment for these patients. Therefore, in this pilot study, the investigators aim to compare the diagnostic performance of 18F-FDG with 68Ga-FAPI-46 as PET-tracer in ER+ breast cancer patients.
- Conditions
- Breast Cancer, Breast Neoplasms, Breast Diseases
- Being tested
- 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI
- Keywords
- 68Ga-FAPI-46, ER+ breast cancer, PET/CT, PET/MRI
- Medical subject headings
- Breast Neoplasms, Breast Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRIDiagnostic test
All participating patients will undergo an additional 68Ga-FAPI- 46 PET/CT and 68Ga-FAPI-46 PET/MRI scan prior to their breast cancer treatment.
| Study group | Role | What they receive |
|---|---|---|
| Additional 68Ga-FAPI-46 PET/CT and PET/MRI exam | Experimental | All participating patients will undergo an additional 68Ga-FAPI- 46 PET/CT and 68Ga-FAPI-46 PET/MRI scan prior to their breast cancer treatment. Receives: Diagnostic Test: 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI |
What is being measured
The primary outcome is the main question the study is designed to answer.
To determine essential input parameters for an adequate sample size calculation for a diagnostic study that compares the diagnostic accuracy of 18F-FDG and 68Ga-FAPI-46 as PET tracer in patients with ER+ breast cancer.
To investigate the proportion of discordant pairs: the number of lesions detected on 18F-FDG PET but not on 68Ga-FAPI-46 PET and the number of lesions detected on 68Ga-FAPI-46 PET but not on 18F-FDG PET.
Measured: Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.
Secondary outcomes (1)
To explore the feasibility of taking biopsies in test-positive patients.
The proportion of 68Ga-FAPI-46-positive 18F-FDG-negative lesions for which performing a biopsy is not feasible.
Measured: Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Mar 2024
- Study start1 Sep 2025
- Primary completionMar 2027 (estimated)
- Study completionMar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by Maastricht University Medical CenterThe sponsor's other registered studies.
- 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
- Interventional
- Phase
- Phase 2
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- Single-group, single-center pilot study
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Maastricht University Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06335069
- Sponsor's protocol ID
- 2023-508066-15
- Other IDs
- 2023
- Status last verified
- Sep 2025
- First submitted
- 11 Mar 2024
- Last updated
- 24 Sep 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Lenaerts M, Duijx LEHW, Mottaghy FM, Bauwens M, van Geel RMJM, Tjan-Heijnen VCG, Backhaus P, Kooreman LFS, Nelemans PJ, Smidt ML, Wildberger JE, van Nijnatten TJA. Per-patient Comparison of [68Ga]-FAPI-46 Versus [18F]FDG as PET Tracers in ER-positive Breast Cancer: Study Design of a Single-centre Prospective Study. J Cancer. 2026 Sep 18;17(10):1767-1772. doi: 10.7150/jca.138448. eCollection 2026.
PubMed 42807247
Study at a glance
From the registry record, last updated by the sponsor on 24 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 18F-FDG Versus 68Ga-FAPI-46 as PET Tracer in ER-positive Breast Cancer - a Pilot Study.
- ClinicalTrials.gov ID
- NCT06335069
- Acronym / sponsor ID
- 2023-508066-15
- Conditions
- Breast Cancer, Breast Neoplasms, Breast Diseases
- Keywords
- 68Ga-FAPI-46, ER+ breast cancer, PET/CT, PET/MRI
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- Maastricht University Medical CenterUniversity, hospital or other
- Study start
- 1 Sep 2025 (actual)
- Primary completion
- Mar 2027 (estimated)
- Study completion
- Mar 2027 (estimated)
- First posted
- 28 Mar 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The extent of breast cancer is an important prognostic factor in patients diagnosed with this disease. Therefore, adequate staging at diagnosis is a requisite for optimal treatment. In all patients diagnosed with locally advanced breast cancer (LABC), distant staging using 18F-FDG PET/CT is recommended. However, the degree of metabolic uptake in the primary breast tumor is significantly lower in the ER+ subtype compared to HER2+ and triple negative breast cancer (TNBC). As a consequence, a suboptimal 18F-FDG uptake in ER+ breast cancer patients can potentially lead to missed distant metastases. Fibroblast-activating protein inhibitor (FAPI) is a recently developed radiotracer that binds to FAP, a stromal antigen overexpressed in more than 90% of epithelial-derived tumors and their metastases. Previous studies all show 68Ga-FAPI PET/CT to have a higher detection rate compared to 18F-FDG PET/CT. However, all previous studies were performed without considering breast cancer subtype. If the metabolic uptake by 68Ga-FAPI-46 is higher in ER+ breast cancer patients, more lesions will be detected, resulting in a more appropriate treatment for these patients. Therefore, in this pilot study, the investigators aim to compare the diagnostic performance of 18F-FDG with 68Ga-FAPI-46 as PET-tracer in ER+ breast cancer patients.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Single-group, single-center pilot study
| Arm | Type | Receives |
|---|---|---|
| Additional 68Ga-FAPI-46 PET/CT and PET/MRI exam | Experimental | Diagnostic Test: 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRIAll participating patients will undergo an additional 68Ga-FAPI- 46 PET/CT and 68Ga-FAPI-46 PET/MRI scan prior to their breast cancer treatment. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Female patient with histopathologically proven ER+ breast cancer.
- Diagnosed with locally advanced (primary tumor >5 cm and/or presence of axillary lymph node metastases) or recurrent breast cancer, or metastatic breast cancer for which 18F-FDG PET/CT or 18F-FDG PET/MRI staging is performed.
- Willing and able to undergo the study procedures.
- Has personally provided written informed consent.
Key exclusion criteria (8 listed)
- Age <18
- Pregnancy
- Patients with secondary malignancies (except non-melanoma skin cancer)
- No 18F-FDG PET/CT or 18F-FDG PET/MRI scan.
- Contra-indications for PET/MRI such as pacemaker, aneurysm clips, metallic device in their body, severe claustrophobia, and severe obesity
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRIAll participating patients will undergo an additional 68Ga-FAPI- 46 PET/CT and 68Ga-FAPI-46 PET/MRI scan prior to their breast cancer treatment. | Diagnostic test | Additional 68Ga-FAPI-46 PET/CT and PET/MRI exam |
Primary outcome
To determine essential input parameters for an adequate sample size calculation for a diagnostic study that compares the diagnostic accuracy of 18F-FDG and 68Ga-FAPI-46 as PET tracer in patients with ER+ breast cancer.
Time frame: Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.
To investigate the proportion of discordant pairs: the number of lesions detected on 18F-FDG PET but not on 68Ga-FAPI-46 PET and the number of lesions detected on 68Ga-FAPI-46 PET but not on 18F-FDG PET.
1 secondary outcome
To explore the feasibility of taking biopsies in test-positive patients.
Time frame: Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Sep 2025.
- Derived from this study: PubMed 42807247Lenaerts M, Duijx LEHW, Mottaghy FM, Bauwens M, van Geel RMJM, Tjan-Heijnen VCG, Backhaus P, Kooreman LFS, Nelemans PJ, Smidt ML, Wildberger JE, van Nijnatten TJA. Per-patient Comparison of [68Ga]-FAPI-46 Versus [18F]FDG as PET Tracers in ER-positive Breast Cancer: Study Design of a Single-centre Prospective Study. J Cancer. 2026 Sep 18;17(10):1767-1772. doi: 10.7150/jca.138448. eCollection 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI in people with Breast Cancer and Breast Neoplasms, run by Maastricht University Medical Center at 1 site in Netherlands.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 24 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Netherlands. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Thiemo JA van Nijnatten, MD, PhD (+31433876910, thiemo.nijnatten@mumc.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To determine essential input parameters for an adequate sample size calculation for a diagnostic study that compares the diagnostic accuracy of 18F-FDG and 68Ga-FAPI-46 as PET tracer in patients with ER+ breast cancer. (time frame: Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06335069, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Sep 2025.