Clonal Hematopoiesis in Giant Cell Arteritis

Not yet recruiting

• Conditions: Systemic Vasculitis Primary; Giant Cell Arteritis; Temporal Arteritis; Clonal Hematopoiesis of Indeterminate Potential; Horton Disease
• Interventions: Diagnostic Test: Temporal arterial biopsy; Diagnostic Test: Whole exome sequencing; Diagnostic Test: Single cell transcriptomics

• Registration Number: NCT06244069
• Lead Sponsor: ASST Fatebenefratelli Sacco

Brief Summary

The goal of this clinical trial is to verify whether CHIP is correlated with the clinical, instrumental, and histological characteristics of GCA, and to characterize the pathogenetic effects of clonal hemopoiesis on vasculitis. The main objective of this study is to verify if clonal hematopoiesis of indeterminate potential (CHIP) affects GCA manifestations, course/response to therapies, and pathogenesis.

Patients who are going to be diagnosed with GCA and for which a fast track is available for a rapid diagnostic work-up including pre-treatment temporal artery biopsy. Patients with CHIP will be identified and characterized by using whole exome sequencing from the peripheral blood samples. The presence and characteristics of CHIP will be correlated with baseline clinical, instrumental, and histologic GCA features.

Detailed Description

GCA is the most frequent idiopathic vasculitis in the elderly, characterized by significant morbidity, with possible formation of aneurysms and arterial dissections and with possible evolution into ischemic tissue events, such as irreversible blindness or stroke. Arterial inflammation is maintained by a leukocyte infiltrate infiltrating the vessel wall through vasa vasorum, composed primarily of macrophages (sometimes structured into granulomas with multinucleated giant cells) and Cluster of Differentiation (CD) 4+ T cells, but also from Cluster of Differentiation (CD) 8+ and dendritic cells. However, there are heterogeneous clinical pictures, in correlation to the spatial distribution of arterial lesions, to the finding of arterial ischemia, aneurysms or any relapses. Even today, there is a need to understand the pathogenetic mechanisms underlying clinical and prognostic differences in GCA and to identify patients with different clinical outcomes and response to therapies in advance.

Clonal hemopoiesis is instead characterized by the presence in the bloodstream of a hematopoietic clone with a selective advantage following somatic mutations, in the absence of other obvious hematological conditions: in fact, it cannot be detected by standard diagnostic tools, but requires a genetic assessment of blood mosaicism or the presence of known relevant mutations. Mutated leukocytes have a more intense inflammatory and atherogenic response with inflammatory stimuli, both infectious and non-infectious, favoring a proinflammatory microenvironment in elderly patients, underlying the concept of "age-related inflammation". One study identified CHIP in 33% of patients with GCA. The investigators hypothesize that specific mutations responsible for the hematopoietic clone could favor a proinflammatory dysregulation of leukocytes within vasculitic lesions, affecting the activity of arterial injury. The purpose of this study is to verify whether CHIP is correlated with the clinical, instrumental and histological characteristics of GCA, and to characterize the pathophysiologic effects of clonal hemopoiesis on vasculitis.

Study Timeline

• Study First Submitted: 2024-01-23
• Status Verified: 2024-02
• Study First Submitted QC: 2024-02-02
• Last Update Submitted: 2024-02-02
• Study First Posted: 2024-02-06
• Last Update Posted: 2024-02-06
• Study Start: 2024-03
• Primary Completion: 2028-03
• Study Completion: 2031-03

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 326

Inclusion Criteria

• Patients with suspected active GCA entering into a fast-track work-up and healthy matched controls.
• Capability of providing valid consent to study enrollment.
• Possibility of performing temporal artery biopsy within three hours from enrollment.

Exclusion Criteria

• Active concurrent viral, fungal or bacterial infections (including active/latent tuberculosis treated for less than 4 weeks, HIV and Hepatitis B/C virus (HBV/HCV) infections.
• Concurrent systemic inflammation not attributable to GCA (inflammatory diseases in treatment-free remission are accepted).
• Use of other immunosuppressive agents in the last 3 months.
• Use of systemic steroids (any dose in the last week, > 15 mg/die of prednisone equivalent in the last month).
• Solid or hematologic malignancies (active or with less than 6 months free of disease or antiblastic chemotherapy (hormone therapy is allowed).
• Previous solid or hematopoietic stem cell transplantation (corneal transplants are allowed).
• Any systemic immunosuppressive or steroidal therapy.
• Chronic renal failure with Glomerular Filtration Rate (GFR) < 45 ml/min *1.73 m2.
• Moderate-severe liver failure (Child-Pugh B or C), hepatitis in stages of activity.
• Diabetes mellitus.
• Heart failure with New York Heart Association score (NYHA) >=2.
• Severe hypoproteinemia/malnutrition.
• Chronic respiratory failure requiring O2 therapy or ventilation therapy at home.
• Any other condition judged by the local investigator as a contra-indication to eligibility.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
GCA patients	Temporal arterial biopsy	Patients who are going to be diagnosed with GCA and for which a fast track is available for a rapid diagnostic work-up including pre-treatment temporal artery biopsy. The main biopsy specimen will be sent for histopathology for clinical diagnosis or final validation, while the remaining specimen (at least 5 mm in length) will be digested to use for research purposes. In the fast-track, patients should rapidly receive a multi-dimensional diagnostic assessment including ultrasonography of the temporal and axillary arteries. Screening for large vessels involvement should be performed according to the local practice by a combination of ultrasonography, Position Emission Tomography (PET) and Magnetic Resonance (MR). Ideally, this assessment should be performed within five days from clinical evaluation.
GCA patients	Whole exome sequencing	Patients who are going to be diagnosed with GCA and for which a fast track is available for a rapid diagnostic work-up including pre-treatment temporal artery biopsy. The main biopsy specimen will be sent for histopathology for clinical diagnosis or final validation, while the remaining specimen (at least 5 mm in length) will be digested to use for research purposes. In the fast-track, patients should rapidly receive a multi-dimensional diagnostic assessment including ultrasonography of the temporal and axillary arteries. Screening for large vessels involvement should be performed according to the local practice by a combination of ultrasonography, Position Emission Tomography (PET) and Magnetic Resonance (MR). Ideally, this assessment should be performed within five days from clinical evaluation.
GCA patients	Single cell transcriptomics	Patients who are going to be diagnosed with GCA and for which a fast track is available for a rapid diagnostic work-up including pre-treatment temporal artery biopsy. The main biopsy specimen will be sent for histopathology for clinical diagnosis or final validation, while the remaining specimen (at least 5 mm in length) will be digested to use for research purposes. In the fast-track, patients should rapidly receive a multi-dimensional diagnostic assessment including ultrasonography of the temporal and axillary arteries. Screening for large vessels involvement should be performed according to the local practice by a combination of ultrasonography, Position Emission Tomography (PET) and Magnetic Resonance (MR). Ideally, this assessment should be performed within five days from clinical evaluation.

Primary Outcome Measures

Name	Time	Method
Correlation of GCA with M-CHIP-driven by DNMT3A mutations	From beginning of study for 11 months	Patients with M-CHIP will be identified by whole exome sequencing from the peripheral blood. The prevalence of DNMT3A-driven M-CHIP will be compared in the GCA patients vs matched controls by Chi-squared test or Fisher test.

Secondary Outcome Measures

Name	Time	Method
Correlation of ischemic features in GCA with specific CHIP mutations	From beginning of study for 11 months	The prevalence of specific CHIP mutations (assessed and defined as above) will be compared between GCA patients with vs without ischemic features (claudicatio mandibularis, soft tissue necrosis, ischemic optic neuropathy) by Chi-squared test or Fisher test.
Correlation of GCA with M-CHIP and L-CHIP clone dimension	From beginning of study for 11 months	Patients with M-CHIP or L-CHIP will be characterized for the dimension of the mutated clone in the peripheral blood by assessing the Variant Allele Fraction (VAF) at whole exome sequencing. The VAF will be compared between the GCA group and the matched controls by an unmatched non-parametric test (Mann-Whitney U test).
Correlation of ischemic features in GCA with CHIP clone dimension	From beginning of study for 11 months	The clone dimension as assessed by VAF (see above) will be compared between GCA patients with vs without ischemic features by the Mann-Whitney U test.
Correlation of GCA with M-CHIP-driven by TET2, ASXL1 and JAK2 mutations	From beginning of study for 11 months	Patients with M-CHIP will be identified by whole exome sequencing from the peripheral blood. The prevalence of TET2, ASXL1 or JAK2-driven M-CHIP will be compared in the GCA patients vs matched controls by Chi-squared test or Fisher test.
Correlation of vascular quantitative score in GCA with specific CHIP mutations	From beginning of study for 11 months	The prevalence of specific CHIP mutations (assessed and defined as above) will be compared between GCA patients with vs without incidence of large vessel involvement and burden of arterial stenosis and dilatation using quantitative activity scores such as Birmingham Vasculitis Activity Score (BVAS) and Vasculitis Damage Index (VDI), using the Mann-Whitney U test.
Correlation of GCA with L-CHIP-driven by DUSP22, FAT1 and KMT2D mutations	From beginning of study for 11 months	Patients with L-CHIP will be identified by whole exome sequencing from the peripheral blood. The prevalence of DUSP22, FAT1 or KMT2D-driven L-CHIP will be compared in the GCA patients vs matched controls by Chi-squared test or Fisher test.
Correlation of rate of complications with specific CHIP mutations	From patients' enrollment for 12 months	GCA patients will be followed prospectively; the prevalence of specific CHIP mutations (assessed and defined as above) will be compared between GCA patients with vs without complications at 12 months (disease relapse, venous thromboembolism, acute coronary syndromes/strokes, infection) by Chi-squared test or Fisher test.
Correlation of histologic features in GCA with specific CHIP mutations	From beginning of study for 11 months	The prevalence of specific CHIP mutations (assessed and defined as above) will be compared between GCA patients with histologic features such as intimal hyperplasia, fragmentation of internal elastic membrane, transmural inflammation, vasa-vasorum neoangiogenesis, and presence of giant cells by Chi-squared test or Fisher test.
Correlation of histologic features in GCA with CHIP clone dimension	From beginning of study for 11 months	The clone dimension as assessed by VAF (see above) will be compared between GCA patients with histologic features such as intimal hyperplasia, fragmentation of internal elastic membrane, transmural inflammation, vasa-vasorum neoangiogenesis, and presence of giant cells, by the Mann-Whitney U test.
Correlation of GCA with M-CHIP and L-CHIP multiple mutations	From beginning of study for 11 months	The prevalence of M-CHIP and L-CHIP driven by multiple mutations as assessed by whole exome sequencing will be compared between the GCA group and the matched controls by Chi-squared test or Fisher test.
Correlation of rate of complications with CHIP clone dimension	From patients' enrollment for 12 months	GCA patients will be followed prospectively; the clone dimension as assessed by VAF (see above) will be compared between GCA patients with vs without complications at 12 months (disease relapse, venous thromboembolism, acute coronary syndromes/strokes, infection) by the Mann-Whitney U test.
Correlation of vascular quantitative score in GCA with CHIP clone dimension	From beginning of study for 11 months	The clone dimension as assessed by VAF (see above) will be compared between GCA patients with incidence of large vessel involvement and burden of arterial stenosis and dilatation using quantitative activity scores such as Birmingham Vasculitis Activity Score (BVAS) and Vasculitis Damage Index (VDI), using Spearman's rank correlation coefficient.