Belatacept Dose Reduction Safety in Kidney Transplant Recipients with a Well-Matched Donor

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What is this study about?

This study is being done in people who have received a kidney transplant. It is testing belatacept, given as an infusion into a vein, as part of the medicines used to prevent the body from rejecting the new kidney. The purpose of the study is to see whether a lower amount of long-term immune-suppressing treatment can be used safely in people who are at lower risk of rejection.

After the transplant, the treatment is given over about one year. One group receives a reduced dose of the immune-suppressing medicine, while the other group receives the standard dose. During the study, the health of the transplanted kidney is followed, and the study team looks for signs of rejection, infection, kidney function changes, and other serious problems. A biopsy, which is a small sample taken from the kidney, may be used to check for rejection.

The study also looks for dnDSAs, which are new antibodies made by the body against the transplanted kidney, and eGFR, a blood test that helps show how well the kidney is working. Other terms used in the study include ddcfDNA, a small amount of DNA from the transplanted kidney that can be found in the blood, and dialysis, a treatment that replaces some kidney function if the transplant stops working.

1 study entry and treatment assignment

After joining the study, you are assigned to one of the study treatment groups in a random way. The study is open label, which means the treatment is known, and assessor blinded, which means the person judging the results does not know which group you are in.

The study compares half-dose and standard-dose immune-suppressing treatment. Immune-suppressing treatment is medicine that lowers the activity of the body’s defense system to help protect the kidney transplant.

The study medicine listed is belatacept (Nulojix 250 mg powder for concentrate for solution for infusion). It is given by intravenous administration, which means through a vein. The listed dose is 6 mg/kg.

2 one-year intervention phase

You receive the assigned immune-suppressing treatment during the one-year intervention phase. This phase is the main treatment period of the study.

During this phase, the study checks whether reducing the maintenance immune-suppressing treatment by half is safe in kidney transplant recipients with a well-matched donor.

The study measures whether you have biopsy-proven rejection during this time. A biopsy is a small sample of tissue taken for testing, and rejection means the transplanted kidney shows signs of being attacked by the body’s defense system.

The study also checks for dnDSAs, which means de novo donor-specific antibodies. These are new proteins in the blood that can recognize the transplant as foreign.

The study checks for ddcfDNA above 1%. This means donor-derived cell-free dna, which is small pieces of genetic material from the transplant found in the blood.

The study records infections, graft loss, and mortality during this phase. Graft loss means the transplanted kidney stops working permanently for more than 3 months, leading to return to dialysis or a repeat transplant.

3 follow-up assessments during the intervention phase

During the one-year intervention phase, your kidney function is checked using eGFR, which means estimated glomerular filtration rate. This is a blood test used to estimate how well the kidney is working.

The study continues to monitor whether rejection occurs and whether dnDSAs appear.

The study continues to monitor safety outcomes, including infections, graft loss, and death.

4 end of intervention phase

At the end of the one-year intervention phase, the study compares the results between the treatment groups.

The main comparison is whether lowering the maintenance immune-suppressing treatment leads to more rejection or more dnDSAs than the standard dose.

The study also compares kidney function, ddcfDNA above 1%, graft loss, infections, and mortality after the one-year intervention phase.

Who Can Join the Study?

Kidney transplant recipient: the person must have received a kidney transplant.
The transplanted kidney must have come from a deceased donor, meaning the kidney was donated after the donor had died.
The kidney transplant must have been done within the last 3 months.
The person must be 18 years of age or older.
The person must be taking tacrolimus-based immunosuppression, meaning a treatment plan that uses tacrolimus to help prevent the body from rejecting the transplanted kidney.
The person must be in CCRS category 1 or 4, which means they are considered to be either low risk or high risk based on this study’s risk scoring system.

Who Cannot Join the Study?

You cannot take part if you have received more than one organ transplant (a transplant of more than one organ).
You cannot take part if you are unable to sign informed consent, which means you cannot legally agree to join the study after it has been explained to you.
You cannot take part if you are Epstein–Barr virus (EBV) sero-negative, meaning blood tests show no signs that you have had this virus before.
You cannot take part if you are cytomegalovirus (CMV) sero-negative and your transplanted organ came from a CMV-positive donor, meaning the donor had signs of this virus in the blood.
You cannot take part if you have an active hepatitis B or hepatitis C infection, meaning the virus is currently causing infection in your body.
You cannot take part if you have DSA MFI greater than 1000, meaning the level of donor-specific antibodies is too high. These are immune proteins that may attack the transplanted kidney.
You cannot take part if you joined another clinical trial less than 3 months before entering this study.
You cannot take part if you are in CCRS category 2 or 3, which means your transplant is in a moderate low or moderate high risk group.
You cannot take part if a kidney biopsy shows rejection of the transplant, with a Banff score of 1A or higher. A biopsy is a small tissue sample, and rejection means the body is attacking the transplanted kidney.
You cannot take part if you are pregnant.

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

Site Name	City	Country	Status
Medical University Of Vienna	Vienna	Austria

Other Sites

No sites found in this category

Trial status

Country	Status	Recruitment Start
Austria	Not yet recruiting	03.08.2026

Trial locations

Investigated drugs:

Belatacept

Belatacept is an immune system medicine given through a vein. In this trial, it is used as part of the transplant rejection prevention treatment for kidney transplant recipients. The study is looking at whether a lower amount of this medicine can still help protect the transplanted kidney while keeping the treatment safe.

Kidney transplant recipient – A kidney transplant recipient is a person who has received a transplanted kidney and is living with a donor organ that must be maintained over time. The condition involves ongoing adaptation of the body to the new kidney and continued monitoring for signs that the immune system is reacting against the transplant. Over time, some recipients may develop rejection, which can gradually reduce kidney function and affect the transplanted organ. Other changes may include the formation of antibodies against the donor kidney and a slow decline in how well the kidney filters blood.

Trial ID:

2025-525091-29-00

Protocol code:

SISTAR

Trial Phase:

Therapeutic exploratory (Phase II)

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Belatacept Dose Reduction Safety in Kidney Transplant Recipients with a Well-Matched Donor

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?