An observational study in Giant Cell Arteritis (GCA), sponsored by University of Edinburgh. Not yet recruiting at 1 site in United Kingdom. Open to participants aged 50 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-16.
Sponsored by University of Edinburgh · Observational
B cells are a component of the immune system which appear be important in causing all forms of cardiovascular disease. Until now, it has not been possible to directly study these cells in living patients (essential to assess their potential as the target of new treatments). For the first time in any cardiovascular disease, this study will apply cutting edge scanning technology to visualise B cells in the blood vessels of giant cell arteritis (GCA) patients. GCA is a common and potentially deadly disorder of the blood vessels which is caused by abnormalities of the immune system. Current treatments are mainly limited to steroids. Unfortunately, these drugs bring tremendous side effects and so there is an urgent requirement to discover alternatives.
Laboratory investigations tell us that B cells are highly present in GCA and so if the proposed scanning technology fails to identify these cells in the blood vessels of participants, then the technology is unlikely to be useful for other cardiovascular diseases. If, however, the study does successfully visualise B cells, this knowledge could pave the way for clinical trials of B cell targeted treatments (already established in other conditions) as steroid alternatives in GCA.
This study aims to map the distribution of the radiotracer zirconium-89 labelled rituximab within the blood vessels of patients with newly diagnosed GCA and compare this with two separate control groups without the condition. This will allow us to determine the role of B cells within this condition, and whether patients would benefit from B cell-depleting treatments such as rituximab.
Giant cell arteritis (GCA) is an auto-immune condition which causes inflammation of medium and large arteries around the body. Previously thought to primarily affect the temporal arteries, there is now an understanding that the disease is more widespread, with most patients demonstrating involvement of the aorta and other large vessels.
Current treatments rely heavily on steroids which can cause significant side effects. Other novel treatments for GCA are also limited, with many patients relapsing once treatment is withdrawn. There is therefore an urgent need for new therapies for GCA, particular in those patients with large vessel involvement (LV-GCA)
B cells - a type of immune cell - are thought to play a key role in causing damage to blood vessels in diseases like atherosclerosis and may be implicated in GCA. Accordingly, a potential treatment approach may be to target B cells using a drug called rituximab (RTX), which is already used in other immune conditions. To explore this possibility safely and effectively, we need a way to see where B cells are in the body, and how they are affected by treatment in GCA. This can be achieved using total body PET scanning with zirconium-89-labeled rituximab.
By injecting patients with zirconium-89-labeled rituximab and then undergoing total body PET scanning, this study hopes to track B cells in real time within the blood vessels of those with GCA. This scan has been used safely in studies of cancer, lung disease, and rheumatoid arthritis.
In summary, the aim of this feasibility study is to:
If successful, this could pave the way for B-cell targeting treatments (like rituximab) that reduce the need for steroids and better control inflammation in LV-GCA.
This will be an observational longitudinal pilot study with a nested baseline case-control comparison. The study will recruit 15 patients with LV-GCA from across Scotland. Participants will attend the University of Edinburgh for a baseline total body 89Zr-RTX PET/CT scan and then receive 4 months of steroid therapy. They will then complete the study with a final total body 89Zr-RTX PET/CT scan. The study will also recruit two control groups. The first will be a group of 10 participants with alternative B cell mediated immune disorders (BCMID group), including (but not limited to) systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, myositis, and Sjogren's syndrome. The second group will include 5 participants with atherosclerosis associated aortic aneurysms. The BCMID control group will receive both baseline and follow-up scans. The AA control group will receive a baseline scan only. All participants will provide a blood sample at each visit in order to compare blood B cells with B cells pictured on the scan. If GCA patients have already had a biopsy of a blood vessel as part of their standard care, the investigators will compare tissue B cells with B cells pictured on the scan. If those in the AA group have any available aortic tissue which has previously been removed at time of aneurysm repair, the investigators will also seek to compare B cell populations within this tissue and on the scan.
As this is a pilot study, and 89Zr-RTX has not previously been used to image disease in GCA, the optimum time period between radiotracer injection and PET scan is not yet known. Accordingly, the first 5 participants in the GCA group will undergo PET scans and coupled blood tests at 3, 5 and 7 days after injection of the radiotracer. This will allow determination of the best time to perform the scan for the remainder of the study.
147 studies on the registry are indexed under Giant Cell Arteritis; 49 are open to participants now.
This study's planned enrollment of 30 is below the median of 128 across 78 observational studies indexed under Giant Cell Arteritis.
Browse Giant Cell Arteritis studies →University of Edinburgh is the lead sponsor of 403 studies on the registry; 64 are open to participants now.
Counted across the registry records on this site, refreshed daily.
For GCA group:
For BCMID group:
For AA group:
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
For GCA group:
For BCMID group:
For AA group:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients with a diagnosis of active, large vessel GCA
Diagnostic Test: Zirconium Zr 89 labelled rituximab
Patients with a diagnosis of atherosclerotic aortic aneurysm
Diagnostic Test: Zirconium Zr 89 labelled rituximab
Patients with a diagnosis of a B-cell mediated inflammatory disorder
Diagnostic Test: Zirconium Zr 89 labelled rituximab
All participants will receive a PET scan with zirconium Zr-89 labelled rituximab. Those in the LV-GCA group will receive a follow-up scan after a period of treatment.
Quantification of vascular 89Zr-RTX uptake
Quantification of vascular 89Zr-RTX uptake compared between: A) those with LV-GCA before and after treatment with steroids B) those with LV-GCA and a control group
Time frame: 0-4 months
Correlation between vascular 89Zr-RTX uptake and peripheral blood B cell populations
Time frame: 0-4 months
Correlation between vascular 89Zr-RTX uptake and temporal artery B cell populations
Time frame: 0-4 months
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Apr 2029, 30 months later.
Of 44 observational studies under Giant Cell Arteritis, half reached primary completion within 45 months of starting (the median), counting those still running; a quarter within 33 and three quarters within 164. This study's planned 30 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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