ClinicalTrials.gov record NCT07535554
The Investigators Will Evaluate the Diagnostic Performance of [18F]-AlF-FAPI-74 PET/CT in Inflammatory Disorders and Compare it With the Current Gold Standard for Inflammation, FDG PET/CT, in Three Patient Cohort: Patients Presenting With Fever of Unknown Origin, IgG4-RD and AxSpA.
Prospective Diagnostic Performance of PET/CT Using the Novel Fibroblast Imaging Tracer [18F]-AlF-FAPI-74 Versus Standard of Care [18F]-FDG in Inflammatory Disorders
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AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
This interventional diagnostic study compares a new PET/CT tracer, [18F]AlF-FAPI-74, with the standard [18F]FDG PET/CT in people with fever of unknown origin, IgG4-related disease, or axial spondyloarthritis. Participants will have PET/CT scans with both tracers; some patients with IgG4-RD or axSpA who start treatment will have a second [18F]AlF-FAPI-74 scan three months after therapy. The study measures how each tracer contributes to diagnosis, finds affected organs, and assesses imaging changes after treatment.
What it is studying. The study compares diagnostic performance of [18F]AlF-FAPI-74 PET/CT to standard [18F]FDG PET/CT. For fever of unknown origin (FUO) the study is set up as a non-inferiority comparison; for IgG4-related disease it evaluates whether [18F]AlF-FAPI-74 performs better in detecting disease extent; for axial spondyloarthritis it examines diagnostic accuracy (distinguishing inflammatory from mechanical back pain) and the tracer's ability to assess treatment response.
What the researchers hope to learn. To evaluate whether [18F]AlF-FAPI-74 PET/CT provides equivalent or improved diagnostic information compared with [18F]FDG PET/CT in FUO, IgG4-related disease, and axSpA; to measure tracer uptake and organ-detection rates; to describe which causes of FUO each tracer detects; and to assess imaging changes after treatment.
What this study is about
The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.
The aim of the study to evaluate the performance of new [18F]-AlF-FAPI-74 PET/CT in three inflammatory disorders (fever of unknown origin, IgG4-related disease and axial spondyloarthritis) and compare with the current stand-of-care [18F]-FDG PET/CT
Interventions being studied
Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.
- Diagnostic test
- [18F]AlF-FAPI-74 PET/CT
Eligibility
The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.
Inclusion criteria
- FUO:
- An illness of more than 3 weeks' duration,
- Temperature exceeding 38.3°C on > 3 occasions, or elevated inflammatory markers on > 3 occasions
- Diagnosis uncertain despite appropriate first-line investigations.
- Inclusion criteria IgG4-RD:
- High clinical suspicion of IgG4-RD by an experienced clinician of Internal Medicine, based on anamnesis, physical examination, first-line investigations and blood tests.
- Patients with a new diagnosis of IgG4-RD on histopathology and need for further assessment of disease extent with PET/CT,
- Relapse of diagnosed IgG4-RD on histopathology according to an experienced clinician of Internal Medicine
- Inclusion criteria AxSpA:
- High clinical suspicion of axial spondyloarthropahy according to an experienced rheumatology (based on inflammary back pain > 3 months, insidious onset, morning stifness, improvement with exercise and worsening in rest, pain worse at night, age at onset <45 years of age, imaging findings).
- Patient has persisting inflammatory back pain after 2 different types of NSAID's (tried for over 2-4 weeks), and is therefore eligible for biological DMARDS therapy.
Exclusion criteria
- Participant is mentally or legally incapacitated, doesn't understand the study design or is not willing or capable to undergo all study-specific procedures.
- Any disorder or condition, which in the Investigator's opinion might jeopardise the participant's safety or compliance with the protocol.
- Any prior or concomitant treatment(s) that might jeopardise the participant's safety or that would compromise the integrity of the Trial.
- Female who is pregnant (urinary hCG test will be performed in every WOCBP), breast-feeding or intends to become pregnant or is of child-bearing potential and not using an adequate, highly effective contraceptive (with a relatively high Pearl Index: natural methods, minipill outside postpartum period, spermicides or condoms in monotherapy or no usage of contraception when sexually active are not accepted).
- Participation in an interventional Trial with an investigational medicinal product (IMP) or device when the trial designs are not considered compatible by the study team.
- Participation in a clinical scientific study in the last 12 months with a radiation exposure caused by the experimental procedures greater than 1 mSv.
- Participant has a known hypersensitivity to [18F]AlF-FAPI-74 or the used excipients.
- Active treatment has already commenced
Study description and what participation involves
The registry record has no detailed description beyond the summary above.
AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴
AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
Participants will undergo diagnostic PET/CT imaging with the new tracer [18F]AlF‑FAPI‑74 and standard [18F]FDG PET/CT for comparison. Each PET/CT visit involves an IV injection of the tracer, about a 60‑minute wait before the scan, a low‑dose CT with oral contrast, and a short observation period afterward for adverse events. If people with IgG4‑RD or axSpA start treatment, a follow‑up PET/CT (including the [18F]AlF‑FAPI‑74 scan) will be performed about three months after treatment to assess changes. Women of child‑bearing potential will have a urine pregnancy test before imaging.
How the study is structured. Interventional diagnostic imaging study without masking. Participants receive both PET/CT scans (standard [18F]FDG PET/CT and the investigational [18F]AlF-FAPI-74 PET/CT). The [18F]AlF-FAPI-74 scan involves an IV injection of tracer (3.5 MBq/kg), a 60-minute uptake period, and a low-dose CT with oral contrast. Patients with IgG4-RD or axSpA who begin treatment will have a follow-up [18F]AlF-FAPI-74 PET/CT about three months after therapy to assess change.
Questions you could ask
These questions are suggestions for a conversation with the study team or your own clinician, not advice.
- The listed sites are in Belgium. Is any of them reachable for me, and does the study help with travel?
- Which of the eligibility criteria would need to be checked with tests before I could join?
More on IgG4-related disease
Important dates
- Study start
- Sep 17, 2025
- Primary completion
- Mar 31, 2029 (estimated)
- Study completion
- Mar 31, 2030 (estimated)
- Target enrollment
- 140 participants (estimated)
- Last updated on registry
- Apr 17, 2026
- Data verified
- Oct 10, 2026
Sponsor and research team
The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.
- Lead sponsor
- Universitaire Ziekenhuizen KU Leuven
Central study contact
If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.
- Lennert Boeckxstaens, MD 📞 +0032 16 34 37 15 ✉ lennert.boeckxstaens@uzleuven.be
Participating sites (1)
- University Hospital LeuvenRecruiting
Leuven, 3000 · Belgium
- Lennert Boeckxstaens, MD · 0032 1634 37 15 · lennert.boeckxstaens@uzleuven.be
Terms used on this page · explanations by MedicalUpdates.ai
- PET/CT
- A scan in which a small amount of a radioactive tracer is injected so that activity in tissues can be seen. Often combined with a CT or MRI scan.
- Inclusion criteria
- The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
- Relapse
- A condition that improved with treatment and has since returned or worsened.
- concomitant treatment
- Other medicines a participant takes during the study. Some must be reported; some are restricted.
- WOCBP
- Studies often ask participants who could become pregnant, or could father a child, to use contraception during the study and for a period afterwards, because the effect of the treatment on a pregnancy is unknown.
- investigational
- A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
- Exclusion Criteria
- The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.
The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.
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