A single center study to evaluate the safety and tolerability of oral Azathioprine in patients with ADPKD

Overview

Sponsor-declared trial summary

Key facts

Sponsor

UZ Leuven

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Not possible to specify

Decision date (initial)

2026-04-21

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

No

Funding sources

Kinderfonds nierziekte en transplantatie

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Safety, Others

To study safety and tolerability of oral azathioprine in patients with kidney and liver involvement of ADPKD.

Secondary objectives 1

1. To study the impact of treatment with oral azathioprine on kidney size, kidney function and liver size

Conditions and MedDRA coding

Autosomal dominant polycystic kidney and liver disease

Study design 1 period

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 10

1. Male and female patients aged ≥18 years at the time of signing the Informed Consent Form (ICF).
2. Diagnosis of autosomal dominant polycystic kidney disease (ADPKD) based on unified criteria (i.e., combination of family history, imaging by ultrasound, MRI or CT, and/or genotyping).
3. Willing and able to comply with scheduled visits, treatment plan, laboratory tests and other study procedures, as judged by the investigator.
4. Voluntary written informed consent of the participant or their legally authorized representative obtained prior to any screening procedures.
5. Use of highly effective contraception during the study period and for at least 3 months after the last dose of study treatment, for all participants of childbearing potential. This includes hormonal contraceptives, intrauterine devices, true sexual abstinence, or commitment to a vasectomized partner.
6. Participants with a confirmed clinical diagnosis of ADPKD. Genetic confirmation of ADPKD is not required for inclusion in the study and may be performed as part of standard clinical care during or after study participation. If a previous genetic test for ADPKD is available, it will be considered valid for the purposes of this study and does not need to be repeated, irrespective of the time since testing.
7. Pharmacogenetic testing for thiopurine S-methyltransferase (TPMT) deficiency is mandatory prior to initiation of study treatment with azathioprine. This testing will be performed during the 4-week screening period. Only participants with an acceptable TPMT genotype (i.e. no homozygous deficiency) will be eligible to start study medication.
8. Patients must be non-transplanted and not receiving immunosuppressive therapy.
9. K-cohort (kidney phenotype): 1. Evidence of rapidly progressive ADPKD, defined by: o Mayo Imaging Classification class 1C, 1D or 1E, and o Screening eGFR ≥ 60 mL/min/1.73 m² 2. Absence of current or prior (at least 12 weeks) treatment with Tolvaptan or somatostatin analogues 3. CT or MR documented presence of at least 3 liver cysts
10. L-cohort (liver phenotype): 1. Presence of ≥20 liver cysts on imaging (MRI or CT), AND 2. Total liver volume (TLV) between 1.8 and 3.2 litres, AND 3. Presence of at least 2 out of the following 5 symptoms indicative of mass effect, regardless of intensity: o Abdominal distension perceived as uncomfortable o Frequent abdominal pain o Early satiety o Nausea (including dyspeptic complaints) o Dyspnea 4. Absence of current or prior (at least 12 weeks) treatment with Tolvaptan or somatostatin analogues

Exclusion criteria 7

1. ADPKD patients that received a kidney and/or liver transplant.
2. Administration of polycystic kidney disease-modifying agents (e.g. tolvaptan, Lanreotide) or interventions (such as cyst aspiration or cyst fenestration) within 12 weeks prior to the screening visit and during the screening period.
3. Concomitant treatment with any other immunosuppressive agent.
4. Women who are pregnant or breastfeeding or women of childbearing potential.
5. Participation in another clinical trial (other investigational drugs or devices at the time of enrolment or within 30 days prior to enrolment).
6. Inability to fully understand the possible risks and benefits related to study participation.
7. Patients with proven TPMT deficiency

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 5

1. % of treatment stop due to leucopenia
2. % of treatment stop due to liver function distrubances
3. % of treatment stop due to subjective intolerance of treatment
4. Number of infections
5. Patient-reported outcome measures (PROs): Validated questionnaires to assess quality of life (QoL) and symptom burden (e.g. abdominal discomfort, fatigue, physical limitation) will be completed at baseline, week 8, week 32, week 56 and week 60.

Secondary endpoints 2

1. Log-transformed annualised relative change of height adjusted total kidney volume (htTKV) and ht total liver volume (htTLV) (%/year) from baseline to week 56 of treatment
2. Change in eGFR from baseline eGFR to week 52 of treatment

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 2

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

UZ Leuven

Sponsor organisation

UZ Leuven

Address

Herestraat 49

City

Leuven

Postcode

3000

Country

Belgium

Scientific contact point

Organisation

UZ Leuven

Contact name

Djalila Mekahli

Public contact point

Organisation

UZ Leuven

Contact name

Djalila Mekahli

Locations

1 EU/EEA country · 1 investigational sites

By country

Investigational sites

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 19 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

1 submissions — initial application plus substantial / non-substantial modifications