CXCR4-PET/CT for Diagnosing Giant Cell Arteritis

Detection of Disease Activity in Giant Cell Arteritis Using CXCR4-PET/CT

Giant cell arteritis (GCA) is the most common vasculitis in the elderly. Accurate diagnosis is of utmost importance in order to then initiate the necessary immunosuppressive therapy. For large-vessel GCA (LV-GCA) involving the aorta and its branches, FDG-PET/CT is the standard in imaging for diagnosis and is recommended by the guidelines. However, this only indirectly visualizes inflammation through vessel wall uptake of glucose. A new PET tracer, 68Ga-pentixafor, is used to visualize the chemokine receptor CXCR4. This receptor is expressed by cells of the immune system. In the context of inflammatory processes, upregulation of CXCL12, the ligand of CXCR4, occurs in affected tissues. The chemotactic effect of this ligand leads to the immigration of CXCR4-positive inflammatory cells into the inflamed area, which can be visualized by PET using the CXCR4-specific tracer 68Ga-Pentixafor. The value of CXCR4-PET should therefore be tested in the context of LV-GCA. This study tests the benefit of CXCR4 in therapy-naïve patients with suspected LV-GCA. For this purpose, patients will receive a FDG-PET and a CXCR4-PET for direct comparison. This is an imaging-only study. Therapy will not be affected by the study. The study is single-arm and not blinded.

Study Overview

• Status: Completed
• Conditions: Vasculitis; Diagnoses Disease
• Intervention / Treatment: Diagnostic test: CXCR4-PET

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Bayern
    • Würzburg, Bayern, Germany, 97074
      • Departement of Internal Medicine II, Rheumatology/Clinical Immunology

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• New diagnosis of GCA within 5 days of diagnosis or initiation or intensification of therapy.
• Evidence of inflammatory activity based on clinical parameters, elevated serologic markers of inflammation (CRP > 1.0 mg/dl), or a positive imaging finding on vasculitis MRI, CCDS, or FDG-PET/CT
• Ability of the patient to provide information
• Exclusion of contraindications for the performance of a PET/CT examination (see below)

Exclusion Criteria:

• Contraindications for the performance of a PET CT examination
• Pregnancy
• Allergies
• Lack of capacity of the patient to give informed consent

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: CXCR4-PET experimental group; In addition to the current standard of imaging in GCA, using FDG-PET/CT, participants receive CXCR4-PET.	Diagnostic test: CXCR4-PET; New imaging modality using CXCR4 for imaging in GCA

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum measurable tracer activity on 68Ga-Pentixafor PET/CT in the area of blood vessels in active GCA	detection of maximum measurable tracer activity on 68Ga-Pentixafor PET/CT in the area of blood vessels after a maximum of 5 days after diagnosis or when acute inflammatory activity of GCA is detected in terms of recurrence.	2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation with clinical parameters	Correlation of the measured tracer activity with clinically and laboratory-chemically available parameters that are collected in clinical routine. These include CRP, peripheral blood leukocyte count, calprotectin, serum amyloid A, haptoglobin and Lactate dehydrogenase and their respective progression.	2 years
Correlation with blood leukocyte count	Correlation of tracer uptake on imaging with CXCR4-positive peripheral blood leukocyte count.	2 years
Comparison to other imaging modalities	Comparison with imaging findings from vasculitis MRI imaging implemented in standard clinical practice, duplex sonography (CCDS), and, if performed as part of routine clinical practice, FDG PET/CT data.	2 years

Collaborators and Investigators

• Sponsor: Matthias Fröhlich
• Investigators: Study Chair: Rudolf A Werner, MD, University Hospital Würzburg Oberdürrbacherstrasse 6, 97080 Würzburg, Germany,

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2021
• Primary Completion (Actual): September 30, 2023
• Study Completion (Actual): September 30, 2023

Study Registration Dates

• First Submitted: October 30, 2022
• First Submitted That Met QC Criteria: October 30, 2022
• First Posted (Actual): November 3, 2022

Study Record Updates

• Last Update Posted (Estimated): December 15, 2023
• Last Update Submitted That Met QC Criteria: December 14, 2023
• Last Verified: December 1, 2023

More Information

Terms related to this study

• Keywords: Imaging; FDG-PET; Vasculitis; LV-GCA; Giant cell arteritis; CXCR4
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Skin Diseases; Immune System Diseases; Autoimmune Diseases of the Nervous System; Autoimmune Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Connective Tissue Diseases; Muscular Diseases; Skin Diseases, Vascular; Vasculitis, Central Nervous System; Polymyalgia Rheumatica; Giant Cell Arteritis; Arteritis; Vasculitis
• Other Study ID Numbers: CXCR4_PET_CT_RZA_V2.1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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