AuthorisedTherapeutic exploratory (Phase II)Interventional

SISTAR: Stratifying Immunosuppression to Allogenic Risk. A randomized, open label, assessor blinded, controlled, non-inferiority, safety study of half- vs standard dose immunosuppression in kidney transplant recipients with a well-matched donor.

This study, called SISTAR, is for people who have had a kidney transplant. Doctors want to see if using a lower dose of anti-rejection medicine (immunosuppression) is as effective and safe as the standard dose, especially when the donor kidney is a very good match for the patient. The medicine being tested is called NULOJIX. The main aim is to check if reducing the dose still prevents the body from rejecting the new kidney within the first year after the transplant. They will also look at how well the kidney works and if there are fewer infections or other problems with the lower dose.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Medical University Of Vienna

Enrolment target

120

Start

17 May 2026

Kidney Transplant Recipient

What is this study about?

Imagine you've had a kidney transplant, which is a life-changing operation. To stop your body's immune system from attacking the new kidney, you need to take special medicines called anti-rejection drugs. These drugs are very important, but they can sometimes have side effects, like increasing your risk of infections.

This study, called SISTAR, is designed to see if we can give people who've had a kidney transplant a lower dose of these anti-rejection medicines. This is particularly interesting for those patients who have a really good match with their kidney donor. A very good match means your body is less likely to see the new kidney as 'foreign', so perhaps you might not need as much medicine to protect it.

The main goal of the study is to check if this reduced dose works just as well as the standard dose in preventing your body from rejecting the kidney in the first year after the transplant. It also looks at how well the new kidney is working, and if there are fewer problems like infections or other side effects with the lower dose. The researchers hope that by carefully reducing the medicine for some people, they can keep their new kidney healthy while also making their daily life better by reducing drug-related side effects.

Key takeaways

This study evaluates lower anti-rejection medicine doses after kidney transplant.
It's for adults with a well-matched donor kidney.
The goal is to reduce side effects while keeping the kidney healthy.
You would receive NULOJIX and have close medical monitoring.
Participation involves regular clinic visits for about a year.

Who may be eligible?

This study is looking for adults who have received a kidney transplant. You need to be at least 18 years old to take part. Both men and women can join.

Crucially, you would be considered for this study if your donor kidney was a very good match for you. This 'well-matched donor' aspect is key because it suggests your body might be more accepting of the new kidney, potentially allowing for a lower dose of anti-rejection medication.

Doctors will carefully check other aspects of your health and your transplant details to make sure this study is right and safe for you. They will explain all the details if you are interested.

Quick self-check

Are you 18 years old or older?
Have you recently had a kidney transplant?
Was your kidney donor a very good match for you?
Are you able to attend regular medical appointments for about a year?

This is a guide only — the research team will confirm whether you can take part.

What does participation involve?

If you decide to take part in this study, you would be randomly assigned to receive either the standard dose of anti-rejection medicine (NULOJIX) or a lower dose. You won't know which dose you're on, nor will the doctors who check your results, to make the study results as fair as possible. You would receive NULOJIX as an infusion (given through a drip).

The study would involve regular visits to the hospital or clinic for about a year after your transplant. During these visits, doctors and nurses would take blood samples, check your kidney's health, and look for any signs of rejection or infection. They will monitor you closely to make sure you are safe and that the treatment is working well. After the first year, there will be further checks to see how you are doing in the longer term.

Potential risks and benefits

Taking part in this study might mean you get a lower dose of anti-rejection medicine, which could potentially lead to fewer side effects from the medication. However, there's also a small chance that a lower dose might not be enough to prevent your body from rejecting the new kidney. The study is designed to carefully monitor you for any problems. As with any medical study, there's always a possibility of unknown risks, but your safety is the top priority, and you'll be monitored closely. Remember, you have the right to leave the study at any time, for any reason, without it affecting your medical care.

Locations (1)

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Austria

Common questions

What is 'immunosuppression'?

It's the medical term for medicines that lower your body's immune system activity. This helps stop your body from attacking and rejecting a transplanted organ like a new kidney.

What does 'well-matched donor' mean?

It means the donor kidney is a very good biological fit for your body, which can sometimes mean your immune system is less likely to try and reject it.

Will I know if I'm getting the lower dose?

No, you won't know which dose you are receiving. This is a common way to avoid bias in studies and ensure the results are accurate.

What is NULOJIX?

NULOJIX is the specific anti-rejection medicine that is being looked at in this study.

What happens if my body starts to reject the kidney?

Your medical team will be closely monitoring you. If there are any signs of rejection, they will adjust your treatment to protect your kidney, just as they would outside of a study.