Evaluation of Kidney Fibrosis Via FAPI PET/CT

July 14, 2026 updated by: Rainer Oberbauer, Medical University of Vienna

Evaluation of Renal Renal Fibrosis Vie FAPI-PET-CT: a Prospective Non-randomized Open-label Single-center Pilot Study

Interstitial fibrosis is a hallmark of progression in chronic kidney disease (CKD), yet it can presently be assessed only by kidney biopsy, which is invasive and prone to sampling error.

In recent years the advances in molecular imaging, especially high spatial and temporal resolution of the scanners and the development of radiopharmaceuticals to visualize metabolic processes or immune cells have been significant, opening promising possibilities in multiple fields. It was demonstrated that in autoimmune diseases as Crohns disease the use of fibrosis markers, as 68Ga-FAPI tracer in PET/MRI could adequately reflect the amount of fibrosis found in histologic work up of tissue specimens in the gut. Also first data in small studies including patients with chronic kidney disease showed promising results indicating that tracer uptake could reflect the degree of fibrosis.

This study aims to investigate the utility of PET/CT imaging with a [68Ga]-DOTA.SA.FAPi tracer to reflect the degree of fibrosis found in the histological work up. We hypothesize that PET/CT findings reflect histological found fibrotic changes in kidney biopsies, potentially offering a superior alternative due to its non-invasive nature and the possibility to capture the entire organ.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background More than 10% of the general population worldwide is affected by chronic kidney disease (CKD) and approximately four million people are living on renal replacement therapy. Main causes for CKD are life style factors as hypertension and diabetes. Modern therapies improve outcome and reduce disease progression and can sustain organ function by reducing fibrosis as disease progression is mostly characterized by progressive tissue remodeling, especially including fibrosis leading to GFR reduction. To quantify the degree of fibrosis an invasive procedure as the kidney biopsy is necessary.The procedure and preparation for native kidney and graft biopsies requires detailed planning as bleeding risk and consecutive consequences of bleeding potentially leading to nephrectomy have to be minimized. Nevertheless, significant complications as erythrocyte transfusions are observed in up to 1,6 % and in 0,3% invasive interventions are needed to stop bleeding following kidney biopsies. These complications occur despite optimal preparation and in significant cases a biopsy is not feasible due to vital platelet inhibition and anticoagulation or these have to be paused for several days prior to biopsy reflecting a significant time loss.

Additionally in patients with a long known CKD and comorbidities (exg. hypertension, hyperglycemia) where a rapid decrease in kidney function also with concomitant significant proteinuria can reflect the natural slope of kidney function decline and histologic biopsy work up eventually often reveals chronic lesions and extended fibrosis as cause for progressive decline in kidney function.

In these cases and due to the mentioned difficulties and significant periprocedural risk, a non-invasive tool to bona fide visualize ongoing processes or existing damage in the kidney is preferable and due to advances in imaging techniques a promising approach.

PET Imaging In recent years the advances in molecular imaging, especially high spatial and temporal resolution of the scanners and the development of radiopharmaceuticals to visualize metabolic processes or immune cells have been significant, opening promising possibilities in multiple fields.

Nowadays widely used FDG PET/CT has proven its use in clinical practice in detecting areas of high metabolism as inflammation or cancer. By the use of alternative radiopharmaceuticals, further processes like blood flow, cell proliferation or receptor distribution in organs can be quantified at the molecular level. Fibrosis evaluation using 68Ga-FAPI tracer demonstrated that in autoimmune diseases as Crohns disease the use of fibrosis markers in PET/MRI could adequately reflect the amount of fibrosis found in histologic work up of tissue specimens in the gut and small studies have already shown promising results in fibrosis evaluation in native kidneys.

Methods We aim to prospectively include 30 patients with different degrees of fibrosis in the kidney biopsy and perform a PET/CT scan using 68Ga-DOTA.SA.FAPi tracer to evaluate a correlation between tracer uptake and the histologic findings.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Austria
    • State of Vienna
      • Vienna, State of Vienna, Austria, 1090

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Histological workup of native kidney present

Exclusion Criteria:

  • Age <18
  • Pregnancy

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: FAPI PET/CT scan
All included patients will have a FAPI PET/CT scan
Diagnostic test: PET/CT scan
Included patients will undergo one PET/CT scan with 68GA-FAPI tracer application

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Correlation of SUVmax and SUVmean with degree of fibrosis in the kidney biopsy assessed by H-score, firbotic area and intensitiy grade.
Time Frame: Patients are included on behalf of the kidney biopsy result and one PET/CT scan will be performed. The statistical analysis and interpretation will be performed immediately after the PET/CT scan.
The Spearman rank correlation coefficient will be used to quantify the associations between the renal PET parameters (SUVmean, SUVmax and SUVpeak) and the histological measures of fibrosis (H-score, fibrotic area and intensity grade). Firbotic area: the percentage of any fibrotic area of the cortical part of the entire biopsy core by visual assessment (in 10% increments); fibrotic grade: an ordinal interstitial fibrosis intensity grade by visual assessment of distension of tubules and staining intensity (0 = ab-sent/nearly absent, I = mild, II = moderate, III = severe) - the most abundant grade was chosen.H-score (0-300) derived from fibrotic area percentages and corre-sponding severity grades (0-3). Statistics will be performed with Rstudio.
Patients are included on behalf of the kidney biopsy result and one PET/CT scan will be performed. The statistical analysis and interpretation will be performed immediately after the PET/CT scan.

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Medical University of Vienna

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Rainer Oberbauer, MD, PhD, Medical University of Vienna, Internal Medicine III, Department of Nephrology and Dialysis

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 5, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 2, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 14, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 17, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 17, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 14, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 1363/2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Data security concerns.

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.

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