Diagnostic Accuracy of 68Ga‑FAPI‑46 PET/CT in Patients with Suspected Giant Cell Arteritis and Polymyalgia Rheumatica

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What is this study about?

The trial focuses on people with giant cell arteritis – polymyalgia rheumatica spectrum disease, a condition that causes inflammation of large blood vessels and can lead to muscle pain and stiffness. The study uses a specially designed imaging agent called [68Ga]FAPI-46, which is given through an injection into a vein. This agent is a tiny amount of a radioactive substance that highlights areas of inflammation when a scan is performed. The imaging technique used is called PET/CT, a test that combines a picture of the body’s structures (CT) with a picture that shows how the injected substance is taken up, helping doctors see active disease.

The purpose of the study is to assess the diagnostic accuracy of this imaging approach in patients with suspected disease. Participants receive the injection, undergo the scan shortly afterward, and then have additional scans after about a month and again after six months of standard treatment to see how the uptake of the agent changes over time. The study follows each person for these visits without involving any experimental drugs.

1 baseline visit

upon joining the trial, attend the first clinic appointment.

receive an intravenous administration of [68ga]fapi-46 at a dose of 250 mbq (mbq is a measure of radioactivity). intravenous means the medicine is given through a vein.

after the injection, wait while the tracer spreads through the body, which typically takes about one hour.

undergo a pet/ct scan (pet/ct combines two imaging techniques to show where the tracer is located). the scan provides the initial images used to assess the disease.

2 standard treatment period

continue any prescribed treatment for giant cell arteritis‑polymyalgia rheumatica spectrum disease as directed by the treating physician.

no additional study procedures are required during this time.

3 first follow‑up visit (28 days)

return to the clinic after 28 days of standard treatment.

receive a second intravenous administration of [68ga]fapi-46 at the same dose of 250 mbq.

wait for the tracer to distribute, then undergo another pet/ct scan.

the images are compared with the baseline scan to evaluate changes in tracer uptake.

4 second follow‑up visit (6 months)

return to the clinic after six months of standard treatment.

receive a third intravenous administration of [68ga]fapi-46 at the dose of 250 mbq.

wait for tracer distribution and have a final pet/ct scan performed.

the final images are used to assess long‑term changes in tracer uptake.

Who Can Join the Study?

You must have a doctor’s suspicion of giant cell arteritis‑polymyalgia rheumatica spectrum disease (GPSD), a condition that can cause blood‑vessel inflammation and muscle pain.
You need to be at least 50 years old.
You must be able to attend all study visits and follow the study’s rules and procedures.
You must be capable of understanding the study information and signing an informed consent form.
Both men and women are eligible to participate.

Who Cannot Join the Study?

Suspected GPSD: If the doctor thinks you may already have giant cell arteritis‑polymyalgia rheumatica spectrum disease, you cannot join the study.
Cranial giant cell arteritis: If you have symptoms, scan results, or a tissue (biopsy) test that shows inflammation of the arteries in the head, you are excluded. (“Cranial” means located in the skull; “arteritis” means artery inflammation.)
Oral glucocorticoid or disease‑modifying anti‑rheumatic drug use: If you are currently taking steroid pills (glucocorticoids) or medicines that change how your immune system works (DMARDs), you cannot participate.
Child bearing potential: Women who could become pregnant are not allowed to join. Women who have gone through menopause (no periods for more than 12 months) are considered not to have child bearing potential.
Research‑related radiation exposure of 5 mSv or more in the past year: If you have already received a high amount of radiation from medical tests or research (5 millisieverts or greater) in the last 12 months, you are excluded.

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

Site Name	City	Country	Status
UMCG	Groningen	The Netherlands

Other Sites

No sites found in this category

Trial status

Country	Status	Recruitment Start
The Netherlands	Not yet recruiting	01.03.2026

Trial locations

Investigated drugs:

(S)-2,2',2''-(10-(2-(4-(3-((4-(2-(2-Cyano-4,4-Difluoropyrrolidin-1-Yl)-2-Oxoethylcarbamoyl)-Quinolin-6-Yl)(Methyl)Amino)-Propyl)Piperazin-1-Yl)-2-Oxoethyl)-68Ga-[1,4,7,10]-Tetraazacyclododecane-1,4,7-Triyl)Triacetate

[68Ga]FAPI-46 is a special imaging medicine that is given through a vein. It contains a tiny amount of a radioactive material called gallium‑68, which lets doctors see where it goes in the body using a PET/CT scanner. The medicine is designed to attach to a protein that is often found in inflamed tissues, especially in the blood vessel walls and joints that can be affected by Giant Cell Arteritis and Polymyalgia Rheumatica. By looking at the pictures from the PET/CT scan, doctors can tell how accurately this test can find the disease in people who are suspected of having it.

Investigated diseases:

Giant cell arteritis–polymyalgia rheumatica spectrum disease – This condition is a combined inflammatory disorder that involves the large arteries, especially those in the head, as well as the muscles around the shoulders and hips. It often begins with symptoms such as headache, scalp tenderness, and pain in the jaw when chewing. Within weeks, patients may develop widespread muscle aching, stiffness, and fatigue, particularly in the neck, shoulders, and hips. The arterial inflammation can extend to other vessels, leading to a gradual increase in pain and tenderness. Over time, the disease may progress in a stepwise fashion, with periods of increased activity followed by relative calm.

Trial ID:

2024-511977-31-01

Trial Phase:

Therapeutic exploratory (Phase II)

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Diagnostic Accuracy of 68Ga‑FAPI‑46 PET/CT in Patients with Suspected Giant Cell Arteritis and Polymyalgia Rheumatica

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?