[AL[18F]F]FAPI-74 for Fever of unknown origin (FUO) | Inflammation of unknown origin (IUO) | IgG4-related disease | Axial spondyloarthritis

Inclusion criteria

• {"criterion_text":"-FUO:-Voluntary written informed consent must be obtained prior to any screening procedures.\n-Subject is aged over 18 years, M/F.\n-Patient underwent a [18F]FDG PET/CT or is planned to have one in the following 4 weeks, and preferably in less than 2 weeks.\n-Female subjects should be (a) post-menopausal, or (b) surgically sterile, or (c) using effective contraceptive with negative pregnancy test.\n-Subjects should fulfil the criteria for classic FUO or IUO\n-o\tFUO •\tAn illness of more than 3 weeks’ duration,\n•\tTemperature exceeding 38.3°C on > 3 occasions,\n•\tDiagnosis uncertain despite appropriate first-line investigations.\n-o\tIUO •\tAn illness of more than 3 weeks’ duration,\n•\tTemperature not exceeding 38.3°C on > 3 occasions,\n•\tRaised inflammatory markers (C-reactive protein > 30mg/dL) on > 3 occasions,\n•\tDiagnosis uncertain despite appropriate first-line investigations.\n-IgG4-RD: -\tVoluntary written informed consent must be obtained prior to any screening procedures.\n-Subject is aged over 18 years, M/F.\n-Patient underwent a [18F]FDG PET/CT or is planned to have one in the following 2 weeks.\n-Female subjects should be (a) post-menopausal, or (b) surgically sterile, or (c) using effective contraceptive with negative pregnancy test.\n-High clinical suspicion of IgG4-RD by an experienced clinician of Internal Medicine, based on anamnesis, physical examination, first-line investigations and blood tests.\n-Relapse of diagnosed IgG4-RD on histopathology, according to the 2019 American College of Rheumatology/European League Against Rheumatism Criteria for IgG4-related Disease, with moderate to high disease activity.\n-AxSpA: -\tVoluntary written informed consent must be obtained prior to any screening procedures.\n-Subject is aged over 18 years, M/F.\n-Female subjects should be (a) post-menopausal, or (b) surgically sterile, or (c) using effective contraceptive with negative pregnancy test.\n-For the inflammatory back pain cohort: \tHigh 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).\n-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.\n-For the mechanical back pain cohort: \tLower back pain of mechanical origin (discus, fact joint, …), confirmed by MRI findings of the lumbar spine.\n-Not caused by trauma."}

Exclusion criteria

• {"criterion_text":"-Subject is unwilling to avoid unusual, unaccustomed, or strenuous physical activity beginning 4 days prior to tracer injection up to 1 day after tracer injection.\n-Subject does not understand the study procedures.\n-Subject is unwilling or unable to perform all of the study procedures or is considered unsuitable in any way by the principal investigator.\n-Subject has had exposure to ionizing radiation (> 1 mSv) in other research studies within the last 12 months.\n-Subject does not agree that incidental findings are communicated to the general practitioner and to the participant him/herself.\n-If applicable: Female who is pregnant, breast-feeding or intends to become pregnant or is of child-bearing potential and not using an adequate contraceptive method.\n-FUO/IUO -\tNone\n-IgG4-RD -\tTreatment for IgG4-RD already commenced before study scan or [18F] FDG PET/CT.\n-AxSpA -\tTreatment with bDMARDS already commenced before study scan."}

Primary endpoints

• {"endpoint_text":"-1.\tFUO/IUO: sensitivity for evaluating the origin of fever and/or inflammation.","definition_or_measurement_approach":"Sensitivity of [18F]AlF-FAPI-74 PET/CT for evaluating origin of fever/inflammation compared versus [18F]FDG PET/CT (study objective is to demonstrate at least non-inferiority of [18F]AlF-FAPI-74 vs [18F]FDG in the FUO cohort)."}
• {"endpoint_text":"-2. sensitivity for diagnosing IgG4-RD in patients with suspected IgG4-RD and assessment of disease extent in patients with confirmed IgG4-RD using the organ detection ratio.","definition_or_measurement_approach":"Sensitivity for diagnosing IgG4-RD by [18F]AlF-FAPI-74 PET/CT versus [18F]FDG PET/CT; assessment of disease extent using organ detection ratio (defined in secondary objectives as percentage of patients with pathological uptake in a specific organ by each tracer out of the total number of patients with pathological uptake in that organ)."}
• {"endpoint_text":"-3. AxSpA: sensitivity and specificity in differentiating inflammatory back pain from mechanical back pain.","definition_or_measurement_approach":"Sensitivity and specificity of [18F]AlF-FAPI-74 PET/CT to differentiate inflammatory back pain (axSpA) from mechanical back pain; semi-quantitative uptake measurements (SUVmax, TBR) are used in secondary objectives to compare cohorts and establish optimal cut-offs."}

Belgium

Earliest CTIS Part Ii Submission Date

25-04-2025

Latest Decision Or Authorization Date

08-05-2025

Processing Time Days

13

Number Of Sites

1

Number Of Participants

135

Primary sponsor

Full Name

UZ Leuven

Organisation Type

Hospital/Clinic/Other health care facility

Country Of Registered Address

Belgium