Exploring the Novel Value of PSMA PET in Sjögren's Syndrome: Integrated Analysis With Established FAPI PET Imaging

December 24, 2025 updated by: Peking Union Medical College Hospital
Primary Sjögren's syndrome (pSS) is a chronic autoimmune exocrinopathy characterized by lymphocytic infiltration, progressive destruction of salivary gland acini, and varying degrees of functional impairment and fibrosis. Conventional imaging provides limited ability to simultaneously evaluate glandular function and inflammatory activity, leading to challenges in disease staging and treatment decision-making. This study explores a conceptual dual-tracer imaging framework using PSMA PET and FAPI PET to delineate complementary biological processes in pSS.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Based on current evidence, salivary gland acinar cells physiologically express PSMA; thus, reduced PSMA uptake may reflect loss of functional parenchyma in patients with pSS. In contrast, activated fibroblasts markedly express FAP, and increased FAPI uptake correlates with ongoing inflammation and fibroblast-driven remodeling. We hypothesize that within the same gland, functional decline (PSMA↓) and inflammatory activity (FAPI↑) may coexist and exhibit a negative correlation, forming a paired imaging biomarker that captures both pathological dimensions. By integrating these two signals into a combined PSMA/FAPI Index, this approach may enable more precise characterization of the "function-inflammation" spectrum in pSS, providing a noninvasive tool for disease staging, monitoring, and potentially predicting therapeutic response.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18-80 years;
  • Fulfillment of the 2016 ACR-EULAR Classification Criteria for pSS at enrollment. OR diagnosis of a solid tumor scheduled for FAPI PET imaging

Exclusion Criteria:

  • Combined with tumors or other connective tissue diseases (for SS group);
  • Patients who are currently using hormones/biological agents (for both groups)；
  • Pregnancy or lactation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: pSS Dual-Tracer Imaging Arm (PSMA + FAPI PET)
This arm includes patients diagnosed with primary Sjögren's syndrome. All participants undergo both PSMA PET and FAPI PET imaging. The PSMA PET scan is used to assess the functional integrity of salivary gland acinar cells, while the FAPI PET scan evaluates inflammatory and fibroblast activity within the same glands. The purpose of this arm is to characterize the functional-inflammatory relationship in pSS and to develop the combined PSMA/FAPI Index for disease staging and activity assessment.
Diagnostic test: ⁶⁸Ga-PSMA PET/CT
PSMA PET imaging performed for clinical evaluation in prostate cancer patients, used as a comparator for physiologic salivary gland PSMA uptake.
Diagnostic test: ⁶⁸Ga-FAPI PET/CT
FAPI PET imaging to assess inflammatory activity (FAPI) in patients with primary Sjögren's syndrome.
Active Comparator: Prostate Cancer PSMA-Only Comparator Arm
This arm consists of patients with prostate cancer who undergo PSMA PET imaging only, representing a population with preserved or physiologic salivary gland PSMA uptake. These scans serve as a reference group for establishing normal or baseline PSMA expression in salivary glands. This comparator arm allows differentiation between disease-related PSMA reduction in pSS and normal tracer distribution observed in patients without salivary gland pathology.
Diagnostic test: ⁶⁸Ga-PSMA PET/CT
PSMA PET imaging performed for clinical evaluation in prostate cancer patients, used as a comparator for physiologic salivary gland PSMA uptake.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Difference in Salivary Gland PSMA Uptake Across Groups
Time Frame: Baseline
Quantitative comparison of PSMA PET uptake parameters (SUVmax, SUVmean) of the parotid glands among three groups: pSS patients, individuals with normal salivary glands, and prostate cancer patients.
Baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Multiglandular PSMA Uptake Comparison
Time Frame: Baseline
Evaluation of PSMA PET uptake (SUVmax, SUVmean) in the parotid, submandibular, and lacrimal glands across the same study groups.
Baseline
Correlation Between PSMA Uptake and Clinical Indicators
Time Frame: Baseline
Correlation of salivary gland PSMA SUV values with clinical, immunological, and functional markers of pSS, including ESR, CRP, IgG, RF, anti-SSA/SSB titers, unstimulated whole salivary flow rate, sialography findings, ESSDAI, and ESSPRI scores.
Baseline
Quantitative and Spatial Relationship Between PSMA and FAPI Uptake Definition
Time Frame: Baseline
  1. Quantitative correlation: Association between PSMA SUV and FAPI SUV in the same glands.
  2. Spatial co-localization: Overlap or complementarity of low-PSMA and high-FAPI regions within individual glands using image fusion and voxel-based analysis (e.g., Dice coefficient).
Baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Peking Union Medical College Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 1, 2025

Primary Completion (Estimated)

January 30, 2026

Study Completion (Estimated)

May 30, 2026

Study Registration Dates

First Submitted

December 24, 2025

First Submitted That Met QC Criteria

December 24, 2025

First Posted (Actual)

January 7, 2026

Study Record Updates

Last Update Posted (Actual)

January 7, 2026

Last Update Submitted That Met QC Criteria

December 24, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Other Study ID Numbers

  • PUMCH-PSS-PSMA

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on PET

Clinical Trials on ⁶⁸Ga-PSMA PET/CT

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Mali

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe