New Analytic Tools for aHUS and C3G Diagnosis (COMPRare)

March 19, 2026 updated by: Mario Negri Institute for Pharmacological Research

Towards the Most Accurate Diagnosis and Monitoring of Complement-mediated Rare Kidney Diseases

This protocol is part of a larger project, COMPRare (COMPlement-mediated Rare kidney diseases), which has been financed on behalf of the EJP RD (European Joint Programme on Rare Diseases) program of EU and is leaded by a scientific consortium from 7 European countries.

The partners (P) of the consortium are:

P1. Radboudumc Amalia Children's Hospital (The Netherlands) P2. Semmelweis University (Hungary) P3. Cordeliers Research Center (France) P4. Max Delbruck Center for Molecular Medicine (Germany) P5. Istituto di Ricerche Farmacologiche Mario Negri (Italy) P6. Lund University (Sweden) P7. Lille University (France)

The general aim of the project is to define new diagnostic tools for complement activation in order to improve patients stratification and follow-up, thereby affecting time and choice of treatment in patients with aHUS and C3G.

Particularly, the specific objectives of the COMPRare are:

  • To develop new standardized analytic assays thereby identifying specific complement prognostic biomarkers for early diagnosis, classification, improved monitoring and treatment of patients with aHUS and C3G;
  • To in-depth characterize patients' complement abnormalities in blood, in patient-derived cells and in kidney biopsies;
  • To identify strategies to classify VUS/LPV
  • To find new pathophysiological pathways involved in aHUS and C3G for further improving disease diagnosis, monitoring and treatment.

The results of these studies will form the basis of personalized treatment with existing and upcoming complement inhibitory drugs for these rare complement-mediated kidney diseases.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

Atypical Hemolytic Uremic Syndrome (aHUS) and C3 Glomerulopathies (C3G) are ultra-rare conditions in which an uncontrolled complement activation results in renal inflammation with thrombotic microangiopathy (TMA) in aHUS and extensive deposition of complement fragments in the kidneys in C3G. In both conditions, these alterations lead to acute and chronic kidney damage and, ultimately, end-stage renal failure. The prevalence of genetic and acquired complement abnormalities varies between the two diseases, but covers mostly the same complement proteins. Blocking the complement system is the treatment of choice in aHUS and may have considerable potential in C3G, as evident from the increasing number of phase 3 trials with complement inhibitory drugs. Timely and accurate diagnosis is still challenging for clinicians, both for aHUS, to differentiate it from other forms of TMA, and for C3G, to distinguish it from other forms of glomerulonephritis (GN). In C3G, kidney biopsy is the diagnostic gold standard but it is not sufficient. Therefore, for both aHUS and C3G, there is an unmet need for accurate testing of genetic and acquired complement abnormalities. Moreover, interlaboratory complement-assays, in particular the tests for the C3 Nephritic Factors (C3NeFs; heterogeneous autoantibodies that stabilize the C3 convertase), vary considerably and, consequently, their standardization is a great necessity. Furthermore, the interpretation of genetic results in aHUS and C3G is not always conclusive.

Variants of Unknown Significance (VUS)/Likely Pathogenic Variant (LPV) in complement genes are often found in aHUS and C3G and require further characterization. A rapid and functional VUS/LPV determination and interpretation could help to better understand the disease pathophysiology and might influence diagnosis and treatment options.

Currently, aHUS patients are effectively treated with the complement C5 inhibiting monoclonal antibodies Eculizumab and Ravulizumab. However, the duration and optimal dose of treatment are debated, particularly in view of the high costs of the drug. Even if recent studies showed that restrictive use of eculizumab is feasible, there is a clear need for biomarkers identification and protocols for monitoring and predicting disease activity in aHUS and C3G patients.

In summary, new analytic tools for further defining the disease profile in blood, (patients) cells and kidney biopsies are needed.

Study Type

Interventional

Enrollment (Estimated)

180

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 Locations

  • Italy
    • BG
      • Ranica, BG, Italy, 24020
        • Centro di Ricerche Cliniche per le Malattie Rare "Aldo e Cele Daccò"

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Aim 1

Inclusion Criteria:

  • Male and female patients (children and adults) with C3G diagnosis
  • Biobank written informed consent

Aim 2 Inclusion criteria

  • Male and female patients (children and adults) with aHUS diagnosis in acute phase (before any treatment), or in remission either untreated or undergoing anti-C5 treatment at standard dosing
  • Written informed consent Exclusion criteria
  • Stx-associated HUS
  • TTP (ADAMTS13<10%)
  • Plasma therapy within 2 weeks from blood sampling

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: Patients
Patients diagnosed with C3G (15 positive and 15 negative for C3NEF) at Centro Daccò, will be identified between those who provided consent to store their samples in the certified biobank (UNI EN ISO 9001:2015; certification n° 6121) of "Centro Daccò" (Centro di Risorse Biologiche Mario Negri - Biobanca Malattie Rare e Renali) and to share them with external laboratories.
Diagnostic test: C3NEF assay
This assay will consist of a dual test, detecting C3 convertase binding C3NEF autoantibodies and measuring the functional consequence by complement alternative pathway (AP) activity using two distinct ELISA designs: C3NEF detection assay and AP activity assay.
Active Comparator: Healthy controls
Healthy donors will be identified between those who provided consent to store their samples in the certified biobank (UNI EN ISO 9001:2015; certification n° 6121) of "Centro Daccò" (Centro di Risorse Biologiche Mario Negri - Biobanca Malattie Rare e Renali). Subject that meet the inclusion/exclusion criteria and for which there is no enough material stored in our biobank, will be recontacted by the investigators of "Centro Daccò" and, if agree, will be asked for serum sampling after informed consent signature.
Diagnostic test: C3NEF assay
This assay will consist of a dual test, detecting C3 convertase binding C3NEF autoantibodies and measuring the functional consequence by complement alternative pathway (AP) activity using two distinct ELISA designs: C3NEF detection assay and AP activity assay.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Determination of assay sensitivity and specificity
Time Frame: At day 0
We estimate that 38 VUS/LPV carrying pedigrees should be enough to demonstrate the sensitivity and specificity of the assay for classifying VUS/LPV.
At day 0

Collaborators and Investigators

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

Sponsor

Mario Negri Institute for Pharmacological Research

Investigators

  • Principal Investigator: Marina Noris, PhD, Istituto Di Ricerche Farmacologiche Mario Negri

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

July 1, 2023

Primary Completion (Estimated)

October 1, 2026

Study Completion (Estimated)

October 1, 2026

Study Registration Dates

First Submitted

August 2, 2023

First Submitted That Met QC Criteria

August 2, 2023

First Posted (Actual)

August 14, 2023

Study Record Updates

Last Update Posted (Actual)

March 23, 2026

Last Update Submitted That Met QC Criteria

March 19, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • COMPRare-IRFMN

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

product manufactured in and exported from the U.S.

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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