A study to evaluate the safety and tolerability of azathioprine in patients with autosomal dominant polycystic kidney and liver disease

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What is this study about?

This study focuses on individuals living with Autosomal Dominant Polycystic Kidney Disease, a condition where fluid-filled sacs, or cysts, grow in the kidneys and sometimes the liver. The purpose of the study is to evaluate the safety and how well the body tolerates the medication azathioprine. This medication is taken as an oral tablet, meaning it is swallowed by mouth.

Participants in the study will take different doses of the medication over a period of time. During the study, health aspects such as liver function, which refers to how well the liver is working, and leucopenia, which is a low level of white blood cells in the blood, will be monitored. The study also looks at how the treatment might affect the size of the kidneys and the liver, as well as the eGFR, a measure used to check how well the kidneys are filtering waste from the blood.

Who Can Join the Study?

Both men and women who are 18 years of age or older at the time they sign the study agreement can join.
Participants must have a confirmed diagnosis of autosomal dominant polycystic kidney disease (ADPKD), which is a condition where fluid-filled sacs called cysts grow in the kidneys and liver.
For those with liver involvement (the L-cohort), there must be at least 20 cysts (small fluid sacs) seen on an MRI or CT scan (special medical pictures of the body), and the total size of the liver must be between 1.8 and 3.2 liters.
Participants in the liver group must also have at least two of the following symptoms caused by the size of the organs: uncomfortable abdominal distension (a swollen or stretched belly), frequent stomach pain, early satiety (feeling full very quickly after starting to eat), nausea (feeling like you might vomit), or dyspnea (difficulty breathing).
For those with kidney involvement (the K-cohort), there must be evidence that the disease is progressing quickly, specifically meeting certain Mayo Imaging Classification categories and having an eGFR (a measure of how well the kidneys filter blood) of 60 or higher.
Participants in the kidney group must also have at least 3 cysts in the liver seen on a CT or MRI scan.
Participants must not be currently taking, or have taken in the last 12 weeks, certain medications called Tolvaptan or somatostatin analogues.
Participants must not have had an organ transplant and must not be taking immunosuppressive therapy (medicines that lower the body’s ability to fight infection).
Before starting the study medicine, patients must undergo pharmacogenetic testing to check for a deficiency in an enzyme called TPMT; only those with a safe level of this enzyme can participate.
Participants must be willing and able to follow the study schedule, including medical visits, treatment plans, and laboratory tests (blood or urine tests).
Participants or their legal representatives must provide written informed consent, which is a signed document showing they understand and agree to take part.
People who are able to become pregnant must use highly effective contraception (methods to prevent pregnancy, such as birth control or devices) during the study and for at least 3 months after the last dose of medicine.

Who Cannot Join the Study?

People who have already had a kidney transplant (a surgery to replace a damaged kidney with a healthy one) or a liver transplant.
People who have used polycystic kidney disease-modifying agents, which are medicines used to slow down the progression of the disease, or had cyst aspiration or fenestration (procedures to drain or open fluid-filled sacs in the organs) within 12 weeks before or during the screening period.
People who are currently taking any other immunosuppressive agents, which are medicines that lower the body’s immune system response.
Women who are pregnant, breastfeeding, or are of childbearing potential (able to become pregnant).
People who are currently taking part in another clinical trial involving different experimental drugs or medical devices.
People who are unable to fully understand the possible risks (harmful effects) and benefits (helpful effects) of joining the study.
Patients with a proven TPMT deficiency, which is a condition where the body lacks enough of a specific enzyme (a protein that helps chemical reactions in the body) needed to break down certain medicines.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Katholieke Universiteit te Leuven	Leuven	Belgium

Other Sites

No sites found in this category

Trial status

Country	Status	Recruitment Start
Belgium	Not yet recruiting	30.03.2026

Trial locations

Investigated drugs:

Azathioprine

Azathioprine is a medication taken by mouth that is being studied to see how safe and well it is tolerated by patients who have polycystic kidney disease that also involves the liver.

Investigated diseases:

Congenital cystic kidney disease

Autosomal dominant polycystic kidney and liver disease – This is a genetic condition where numerous fluid-filled sacs, known as cysts, grow in the kidneys and the liver. As these cysts increase in size and number over time, they cause the organs to expand significantly. The growing cysts can gradually take up more space within the organs, affecting their normal structure. This process can lead to an increase in the overall volume of both the kidneys and the liver. The progression typically occurs slowly over many years.

Trial ID:

2025-524313-86-00

Trial Phase:

Therapeutic exploratory (Phase II)

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A study to evaluate the safety and tolerability of azathioprine in patients with autosomal dominant polycystic kidney and liver disease

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?