[18F]F-AraG PET Imaging in Alzheimer's Disease

Total-Body [18F]F-AraG PET/CT Imaging to Quantify CNS and Systemic T Cell Involvement in Alzheimer's Disease

This study evaluates the use of [18F]F-AraG PET/CT imaging to quantify activated T cell involvement in patients with Alzheimer's disease (AD). Participants will undergo total-body dynamic PET imaging to assess tracer uptake in the brain and peripheral organs. Results will be compared between participants with AD and healthy controls to characterize both central nervous system and systemic immune alterations in AD

Study Overview

• Status: Not yet recruiting
• Conditions: Alzheimer Disease (AD)
• Intervention / Treatment: Drug: Drug: [18F]F-AraG (PET tracer)

Detailed Description

Alzheimer's disease (AD) is known to involve neuroinflammation, but the role of T cell-mediated adaptive immunity remains poorly understood. This study uses [18F]F-AraG, a PET tracer that preferentially accumulates in activated T cells, to noninvasively assess immune-metabolic activity in the brain and peripheral organs in patients with AD.

Participants will undergo high-sensitivity total-body dynamic PET imaging using the uEXPLORER system. Intracerebral and systemic immune-metabolic activity will be assessed by analyzing total body [18F]F-AraG biodistribution and kinetics. .

The study will compare imaging metrics between AD participants and healthy controls.

• Study Type: Interventional
• Enrollment (Estimated): 10
• Phase: Phase 2

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age ≥ 55 years
2. Prior volumetric brain MRI available. If the prior MRI scan is not acquired within 6 months of [18F]F-AraG imaging or if the investigator determines that prior MRI scan cannot be used, a new MRI scan will be acquired.
3. Able to tolerate a PET scan, and willingness and ability to comply with all protocol required procedures.
4. For participants of reproductive potential - defined as individuals who have not been post-menopausal for at least 24 consecutive months (i.e., who have had menses within the preceding 24 months), or who have not undergone surgical sterilization, specifically hysterectomy and/or bilateral oophorectomy or bilateral salpingectomy - willingness to use effective double barrier contraceptive methods (excluding withdrawal or timing methods) up to 1 day after the administration of [18F]F-AraG
5. Subjects with possible or probable AD based on the NIA-Alzheimer's Association working group's diagnostic guidelines for AD.
6. Have a study partner who has significant interaction with the subject and can report on the subject's activities of daily living.

Exclusion Criteria:

1. Clinically significant psychiatric disease other than depression.
2. Structural brain abnormalities on MRI (e.g. large infarct or mass) likely to interfere with interpretation of a PET scan.
3. History of significant alcohol or substance abuse/dependence within the past 5 years.
4. Non-study related radiopharmaceutical imaging or treatment procedure within 7 days prior to the PET imaging session.
5. Current or recent investigational drug use, defined as receiving any investigational medications or participation in another investigational drug trial within the last 30 days.
6. Serious comorbidities (malignant and nonmalignant disease or other conditions) that in the opinion of the investigator could compromise study objectives.
7. Conditions affecting immune function or conditions caused by immune system malfunction that could interfere with imaging, including known inflammatory or immune disorders, systemic malignancy, or chronic viral infections.
8. Pregnant or nursing individuals. All participants of reproductive potential will undergo a urine or HCG serum pregnancy test with a sensitivity of at least 25 mIU/mL at screening and on the day of PET/CT imaging.
9. Prior allogeneic stem cell or solid organ transplant.
10. Previously diagnosed myelodysplasia syndrome or history of lymphoproliferative disease prior to study entry.
11. Active systemic autoimmune diseases.
12. Self-reported history of dysphoria or anxiety in closed spaces (i.e., uncontrolled claustrophobia).
13. Concurrent or prior enrollment in a separate research study involving a PET scan performed within the last 12 months for research purposes only.
14. Body weight is more than 240 kg (529 pounds)
15. Recent use of medications containing guanosine or cysteine analogs.
16. Any other criteria which would make the participant unsuitable for study participation, as determined by the Principal Investigator.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm 1: Alzheimer's Disease Participants; Receive [18F]F-AraG PET/CT imaging	Drug: Drug: [18F]F-AraG (PET tracer); Dose: ~5 mCi IV bolus. Procedure: Total-body PET/CT dynamic imaging. Blood samples will be collected during scan.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
[¹⁸F]F-AraG uptake in the brain of patients with AD	To assess presence of activated T cells uptake in patients with AD, static frames from PET/CT scans at 50 minutes post-injection will be analyzed to quantify the intracerebral uptake in patients with AD. Standardized uptake values will be reported for patients with AD and will be statistically compared between AD and healthy control participants.	Imaging visit (~70 minutes)
[¹⁸F]F-AraG uptake kinetics in the brain of patients with AD	To assess kinetics of [¹⁸F]F-AraG uptake in patients with AD, ~70-min dynamic PET/CT scans will be analyzed to generate time-activity curves (TACs) in the brain. Kinetic modeling will be applied to extract uptake kinetic parameters. Uptake kinetics will be reported for patients with AD and will be statistically compared between AD and healthy control participants.	Imaging visit (~70 minutes)
[¹⁸F]F-AraG vascular kinetics in the brain of patients with AD	To assess vascular kinetics of [¹⁸F]F-AraG in patients with AD, dynamic PET/CT scans will be analyzed with high temporal resolution kinetic modeling in the brain. Vascular kinetic parameters will be reported for patients with AD and will be statistically compared between AD and healthy control participants.	Imaging visit (~70 minutes)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Systemic [¹⁸F]F-AraG uptake in patients with AD	To assess systemic immune activation in patients with AD, static frames from PET/CT scans at 50 minutes post-injection will be analyzed to quantify the whole-body uptake in patients with AD. Standardized uptake values will be reported in multiple tissues for patients with AD and will be statistically compared between AD and healthy control participants.	Imaging visit (~70 minutes)
Systemic [¹⁸F]F-AraG uptake kinetics in patients with AD	To assess systemic kinetics of [¹⁸F]F-AraG uptake in patients with AD, ~70-min dynamic PET/CT scans will be analyzed to generate time-activity curves (TACs) in the multiple tissues. Kinetic modeling will be applied to extract uptake kinetic parameters. Uptake kinetics in multiple tissues will be reported for patients with AD and will be statistically compared between AD and healthy control participants.	Imaging visit (~70 minutes)

Collaborators and Investigators

• Sponsor: CellSight Technologies, Inc.
• Collaborators: University of California, Davis

Study record dates

Study Major Dates

• Study Start (Estimated): May 16, 2026
• Primary Completion (Estimated): September 16, 2029
• Study Completion (Estimated): December 16, 2029

Study Registration Dates

• First Submitted: May 1, 2026
• First Submitted That Met QC Criteria: May 20, 2026
• First Posted (Actual): May 28, 2026

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Mental Disorders; Neurocognitive Disorders; Dementia; Tauopathies; Neurodegenerative Diseases; Alzheimer Disease; Pharmaceutical Preparations
• Other Study ID Numbers: CST_Neuro_201_UCD

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No