18F-FDG Versus 68Ga-FAPI-46 as PET Tracer in ER-positive Breast Cancer.

NCT06335069 | Recruiting Phase 2 DMC

• 1 other identifier: 2023-508066-15
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief 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. 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

Keywords

68Ga-FAPI-46; ER+ breast cancer; PET/CT; PET/MRI

Outcome Measures

Primary Outcomes (1)

• 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.

  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.

  Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.

Other Outcomes (2)

• To provide preliminary estimates of the proportion of 68Ga-FAPI-46-positive and 18F-FDG-positive lesions confirmed as true positives and false positives verified by a histological biopsy (gold standard) in patients with ER+ breast cancer.

  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 differences in accuracy between 68Ga-FAPI-46 PET/CT versus 68Ga-FAPI-46 PET/MRI.

  Patients will be followed from diagnosis until the additional imaging exams are performed, within 20 working days both PET exams will be performed.

Study Arms (1)

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.

Diagnostic Test: 68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI

Interventions

68Ga-FAPI-46 PET/CT and 68Ga-FAPI-46 PET/MRI DIAGNOSTIC_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.

Additional 68Ga-FAPI-46 PET/CT and PET/MRI exam

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Only females are eligible to participate in this study.
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Maastricht University Medical Center: lead

Study Sites (1)

Maastricht University Medical Center+

Maastricht, 5800, Netherlands

RECRUITING

MeSH Terms

Conditions

Breast Neoplasms; Breast Diseases

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Skin Diseases; Skin and Connective Tissue Diseases

Central Study Contacts

Thiemo JA van Nijnatten, MD, PhD

CONTACT

+31433876910; thiemo.nijnatten@mumc.nl

Lisa EHW Duijx, MSc

CONTACT

+31639289798; lisa.duijx@mumc.nl

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Single-group, single-center pilot study

Study Record Dates

• First Submitted: March 11, 2024
• First Posted: March 28, 2024
• Study Start: September 1, 2025
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027
• Last Updated: September 24, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

NL (1)