Detection of Circulating Kidney DNA in Kidney Transplant Patients Facing an Episode of Graft Rejection (DART-RREGREF)

In France, 3,500 kidney transplants are carried out per year; and 40,000 people succeed in 2019 with a kidney transplant. Despite regular medical monitoring, nearly 30% of transplant patients will develop rejection. Currently, only solid biopsy of the graft makes it possible to establish the diagnosis of graft rejection, and to characterize its cellular origin based on the Banff classification.

Several studies have shown the possibility of identifying the tissue origin of DNA circulating in the blood, in healthy subjects, on the basis of the epigenetic properties of circulating DNA. In addition, in kidney transplant subjects, an increase in the quantity of circulating DNA originating from the graft in the blood and urine has been shown as well as an increase in urinary chemokine levels during renal dysfunction (notably dismiss). Thus, the company CGenetix in partnership with INSERM units 1155 and 1151 is developing a method to identify and characterize kidney transplant rejection early, through the detection of epigenetic biomarkers on circulating DNA targeting different fractions of the kidney (glomerular, tubular, peritubular capillary and vascular). The main objective is to study the diagnostic performance of the quantity of DNA of renal origin in kidney transplant patients in the blood and in the urine (expressed in copies/ml) for the diagnosis of type Rejection mediated by kidneys. antibody (ABMR) established by kidney graft biopsy (gold standard) and according to the Banff 2022 classification.

Study Overview

• Status: Not yet recruiting
• Conditions: Kidney Transplant Patients Eligible for a Solid Biopsy

Detailed Description

Kidney transplantation remains the standard treatment for patients with end-stage renal disease. It provides the patient with a better quality of life1 and a better chance of survival, for a reduced cost of care compared to dialysis. While more than 3,000 kidney transplants are carried out each year in France, more than 20,000 candidates are registered on the transplant waiting list, revealing a severe shortage of grafts. Limiting the degradation of the kidney graft would make it possible to avoid the return of patients to dialysis and limit the shortage of grafts.

At the diagnostic level, routine monitoring of graft functionality after kidney transplantation is based on the use of non-specific markers, such as serum creatinine (allowing the estimation of glomerular filtration rate or GFR) and proteinuria. Definitive diagnosis of renal allograft dysfunction still requires invasive allograft biopsy, which remains the gold standard for evaluating graft status. The anatomopathological diagnosis of renal graft dysfunction is based on the Banff classification, and makes it possible to examine the immune infiltrate and cellular lesions of the graft in order to make a diagnosis on: 1-the presence of graft rejection or other attacks and 2- the anatomical compartment affected by the pathology: tubular, vascular, interstitial or glomerular.

The start-up CGenetix offers an original approach to predict and characterize renal graft rejection/dysfunction based on the quantification of epigenetic signatures present on donor-cell-free DNA. In 2018, Moss et al. are developing a deconvolution model capable of identifying the tissue origin of circulating DNA by taking advantage of its epigenetic properties. The study confirmed that the free DNA circulating in healthy subjects comes mainly from blood cells and endothelial cells, but not from kidney cells.

In this protocol, 319 kidney transplant patients will be recruited from the Renal Transplantation departments of Pitié-Salpêtrière and Necker. Patients will be recruited into the study at the time of their hospitalization for renal biopsy for cause/indication (inclusion visit). Urine and blood samples will be taken within 24 hours before the kidney biopsy is performed.

The quantities of circulating DNA of renal origin (total kidney biomarkers (x2), specific tubules (x2), specific glomeruli (x2), specific peritubular capillaries (x2) and specific arteriolar capillaries (x2)) will be determined by digital PCR and expressed in copy/ml in blood and urine samples.

The main evaluation criterion of the research is the area under the ROC curve of the ABMR type rejection prediction models according to renal biopsy and with as covariates of interest the quantities of circulating DNA of renal origin (kidney biomarkers total (x2), specific tubules (x2), specific glomeruli (x2), specific peritubular capillaries (x2) and specific arteriolar capillaries (x2)) determined by digital PCR and expressed in copy/ml in blood and urine The final objective of this study protocol consists of i) prospectively validating the performance of the diagnostic test proposed by CGenetix and its partners INSERM 1155 and 1151 and urinary chemokines to non-invasively diagnose acute renal graft rejection and ii ) study its ability to diagnose the different types of renal transplant rejection (ABMR, TCMR, Mixed, Without rejection) The research hypotheses are: i) an AUC ≥ 0.80 / Sensitivity and specificity ≥ 80% for each biomarker taken individually; ii) an AUC ≥ 0.85 / Sensitivity and specificity ≥ 85% for the multimodal prediction model.

• Study Type: Observational
• Enrollment (Estimated): 319

Contacts and Locations

• Study Contact: Name: Anne BISSERY; Phone Number: +33 1 42 16 24 32; Email: anne.bissery@aphp.fr
• Study Contact Backup: Name: Pierre GALICHON, Pr; Phone Number: +33 1 42 17 72 29; Email: pierre.galichon@aphp.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Kidney transplant patients eligible for a solid biopsy

Description

Inclusion Criteria:

• Age ≥ 18 ans
• Patient living with at least one functioning kidney graft
• Summoned to perform a kidney biopsy for cause/indication at the Pitié Salpêtrière Hospital or at the Necker Hospital
• Having been informed of the study and not opposing the study
• Benefiting from a social security system (excluding AME)

Exclusion Criteria:

• Under legal protection measure (curatorship or guardianship, under judicial protection).

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The area under the ROC curve of ABMR rejection prediction models according to kidney biopsy and with renal circulating DNA quantities as variables of interest	The probability of ABMR rejection, established by kidney graft biopsy and according to the Banff 2022 classification, will be predicted with logistic regression models which will integrate the number of copies/ml of the 10 genes measured by PCR in blood or urine. and tested individually.	At the time of the biopsy for suspicion of graft rejection

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The area under the ROC curve of TCMR rejection prediction models according to kidney biopsy and with renal circulating DNA quantities as variables of interest	The probability of TCMR rejection, established by kidney graft biopsy and according to the Banff 2022 classification, will be predicted with logistic regression models which will integrate the number of copies/ml of the 10 genes measured by PCR in blood or urine. and tested individually.	At the time of the biopsy for suspicion of graft rejection
The area under the ROC curve of mixed rejection prediction models according to kidney biopsy and with renal circulating DNA quantities as variables of interest	The probability of mixed rejection, established by kidney graft biopsy and according to the Banff 2022 classification, will be predicted with logistic regression models which will integrate the number of copies/ml of the 10 genes measured by PCR in blood or urine. and tested individually.	At the time of the biopsy for suspicion of graft rejection
The area under the ROC curve of glomerulitis-type rejection prediction models (≥g1) according to kidney biopsy and with renal circulating DNA quantities as variables of interest	The probability of glomerulitis-type rejection, established by kidney graft biopsy and according to the Banff 2022 classification, will be predicted with logistic regression models which will integrate the number of copies/ml of the 10 genes measured by PCR in blood or urine. and tested individually.	At the time of the biopsy for suspicion of graft rejection
The area under the ROC curve of tubulitis-type rejection prediction models (≥t1) according to kidney biopsy and with renal circulating DNA quantities as variables of interest	The probability of tubularitis-type rejection, established by kidney graft biopsy and according to the Banff 2022 classification, will be predicted with logistic regression models which will integrate the number of copies/ml of the 10 genes measured by PC	At the time of the biopsy for suspicion of graft rejection
The area under the ROC curve of vascularitis-type rejection prediction models (≥v1) according to kidney biopsy and with renal circulating DNA quantities as variables of interest	The probability of vascularitis-type rejection, established by kidney graft biopsy and according to the Banff 2022 classification, will be predicted with logistic regression models which will integrate the number of copies/ml of the 10 genes measured by PCR in blood or urine. and tested individually.	At the time of the biopsy for suspicion of graft rejection
The area under the ROC curve of capillaritis-type rejection prediction models (≥ptc1) according to kidney biopsy and with renal circulating DNA quantities as variables of interest	The probability of capillaritis-type rejection, established by kidney graft biopsy and according to the Banff 2022 classification, will be predicted with logistic regression models which will integrate the number of copies/ml of the 10 genes measured by PCR in blood or urine. and tested individually.	At the time of the biopsy for suspicion of graft rejection
Areas under the ROC curve of rejection prediction models according to renal biopsy and with as covariates of interest the quantities of urinary chemokines (CXCL9 and CXCL10) determined by ELISA and expressed in pg/mL in urine	The main endpoint of the research is the area under the ROC curve of the ABMR, TCMR, mixed rejection prediction models according to renal biopsy and with the quantities of urinary chemokines (CXCL9 and CXCL10) as covariates of interest. ) determined by ELISA and expressed in pg/mL in urine	At the time of the biopsy for suspicion of graft rejection

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Collaborators: Institut National de la Santé Et de la Recherche Médicale, France; CGenetix
• Investigators: Principal Investigator: Pierre GALICHON, Pr, Assistance Publique - Hôpitaux de Paris

Study record dates

Study Major Dates

• Study Start (Estimated): June 10, 2024
• Primary Completion (Estimated): February 11, 2026
• Study Completion (Estimated): February 11, 2026

Study Registration Dates

• First Submitted: April 2, 2024
• First Submitted That Met QC Criteria: April 2, 2024
• First Posted (Actual): April 8, 2024

Study Record Updates

• Last Update Posted (Actual): April 8, 2024
• Last Update Submitted That Met QC Criteria: April 2, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: Graft rejection; renal circulating DNA; performance of the diagnostic test
• Other Study ID Numbers: APHP231661

Drug and device information, study documents

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