A Novel Ureteric Stent in Kidney Stone Patients and Oncology Patients Compared to a Conventional JJ Stent (CASSETTE)

May 6, 2026 updated by: University of Southampton

Two Single Arm, Multicentre Unblinded First-in-human Trials Investigating a Novel Ureteric Stent to Determine the Reduction of Encrustation, Biofilm Deposition and Complications Compared to a Conventional JJ Stent

Urological stents and catheters often lead to inflammation, causing pain and infection in the urinary tract. Moreover, 80% of stents are associated with pain, negatively impacting on QoL and mental health. Offering novel designs with significantly lower E&B leads to a reduction in UTIs and improves QoL. Reducing hospital admissions (from 3 to 1 per patient, annually) would free >100,000 bed-nights, allowing the elderly to regain independence. Our proposed research could have a significant impact towards fulfilling the 'healthy-ageing' Grand Challenge. Additionally, the novel stent reduces prevalence of infections and therefore, of antibiotic prescriptions contributing to the Global AMR challenge.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Ureteric stents and catheters are deployed clinically as temporary measures to restore urinary drainage, in patients with kidney stones, tumours and strictures. Prevalence of these increases with age. Device-associated encrustation-and-biofilm-formation (E&B) are key complications, leading to urinary-tract-infections (UTIs) in >90% of stents, causing stent blockage and favouring development of antibiotic resistance.

UTIs are a significant cause of morbidity, especially among the elderly population, with 4,835 deaths in England and Wales reported in 2012. The National Institute for Health Research reported that 1-3% of all primary care consultations concern UTI-related symptoms, leading to 13.7% of antibiotic prescriptions globally. The report also revealed that >92m people globally are diagnosed with UTIs annually.

Urological-device-associated infections significantly compromise patient' quality of life and the effectiveness of services, imposing a £2.5b annual burden on the NHS. Patients' exposure to hospital environment and general anaesthetic use impact on Quality-of-Life (QoL), resulting in unnecessary hospital bed-nights. A novel urological stent has been developed which is associated with significantly reduced particle deposition , potentially extending the stent's lifetime, resulting in reduced hospitalisation and improved QoL.

Urological stents and catheters often lead to inflammation, causing pain and infection in the urinary tract. Moreover, 80% of stents are associated with pain, negatively impacting on QoL and mental health. Offering novel designs with significantly lower E&B leads to a reduction in UTIs and improves QoL. Reducing hospital admissions (from 3 to 1 per patient, annually) would free >100,000 bed-nights, allowing the elderly to regain independence. Our proposed research could have a significant impact towards fulfilling the 'healthy-ageing' Grand Challenge. Additionally, the novel stent reduces prevalence of infections and therefore, of antibiotic prescriptions contributing to the Global AMR challenge.

Considering only onco-urological patients, >30,000 stents are inserted every year across 200 NHS units. Due to stent failures, each patient undergoes 3 to 6 replacements, resulting in >90,000 stent replacements. Under the current tariff-based system, hospitals are paid for each intervention, costing the NHS >£3,500, bringing the total cost of replacements to ~£315m annually. Unnecessary replacements increase the number of bed-nights and use of anaesthetics. A longer-lasting stent means that each patient comes to the hospital ideally only once, reducing their exposure to the hospital environment and anaesthetic-associated risks. Additionally, under the current model hospitals would improve their quality of service and save at least 2 bed-nights per patient. The NHS is moving towards a "block contract" model, meaning that hospitals will receive a lump sum for the year and they'll regularly monitor budgets and improve cost efficiency where possible. Improved stents will allow the same urology budget to deliver more healthcare, reducing theatre time for stent insertion-and-replacement. This innovative stent design offers a potential annual saving of >£210m for the NHS, allowing hospitals to reallocate their resources. Today E&B is still a major determinant of stent failure and associated side effects. The trial aims to address this challenge through the novel stent, and if equivalent safety and improved efficacy are demonstrated, anticipate market launch via third-party suppliers 2-3 years post project.

Solutions to break this pathway (stent presence >> inflammation, pain and infection) have been developed, including materials (e.g. metallic alloys, polymers, biodegradable and drug-eluting materials), coatings (e.g. heparin, chitosan, hydrogel, carbon) and shapes (e.g. double-J, loop, mesh, string, expandable) to improve the efficacy and safety of stents. Despite all these advances, there is still a significant prevalence of E&B. This is also due to the lack of studies correlating fluid dynamic metrics with deposition of particles causing E&B. The lead applicant's PhD investigated the mechanisms of particle deposition in urological stents, and successfully determined fluid dynamic parameters governing particle deposition on ureteric stents and catheters. The research led to developing a stent with specially shaped side-holes that prevent stagnation points (i.e., areas of low flow that cause particles to settle and E&B). These developments demonstrated >80% reduction in particle deposition at side-holes, in-vitro. Their innovative architecture can be implemented on stents and catheters. The technology, including the stent design and manufacturing process, is protectable - Patent# WO2019048860A1, WIPO(PCT). These results were further validated in an animal study (6 pigs: 3 novel-design-stent vs 3 conventional-design-stent for a 4-weeks period) at Stone-Centre at Vancouver-General-Hospital (VGH), a centre of excellence in animal studies on urological products. The study (available upon request) concluded that the functionality of stents with novel side-holes is the same as that of standard stents in terms of safety. Specifically, the novel stent does not result in increased risk of irritation, inflammation and hydronephrosis. Furthermore, SEM/EDX imaging showed that the novel design decreased the build-up of particles on the stent surface. Thus, it demonstrated significant potential for the new side-hole configuration to change patterns of particle deposition on the stent's surface, decreasing encrustation

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United Kingdom
    • England
      • Southampton, England, United Kingdom, SO16 6YD
        • Recruiting
        • University Hospital Southampton
        • Contact:
    • London
      • London, London, United Kingdom, W1G 8PH
        • Recruiting
        • University College Hospital London
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Aged 18 years or over
  2. Ureteric stents clinically indicated either due to kidney stones or abdominal/pelvic cancers compressing ureters
  3. Previous experience with ureteric stents
  4. Awaiting insersion/replacement of stents
  5. Ability to give consent
  6. Ability to interact with study documentation
  7. Sufficient English to complete study documentations and questionnaires

Exclusion Criteria:

  1. Expected survival <4months
  2. Unfit for stent insertion
  3. Unable to comply with study processes Pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Kidney Stone cohort
Experimental ureteric stent with specially shaped side-holes that prevent stagnation points (i.e., areas of low flow that cause particles to settle and E&B)
Device: Experimental ureteric stent with specially shaped side-holes that prevent stagnation points (i.e., areas of low flow that cause particles to settle and E&B)
Kidney stone patients and Oncology patients admitted to either the University Hospital Southampton (UHS) or University College London Hospital (UCLH) for management of kidney stones or for the management of urine drainage in ureter will have a novel ureteric stent instead of their planned conventional stent. The novel stent will be removed after 4 weeks (kidney stone patients) or 25 weeks (oncology patients). Recruitment to the cohort of oncology patients will only commence once the results for kidney stones patients have been reviewed.
Other: Qualitative interview
Kidney stone patients, Oncology patients and doctors will be interviewed about their experience of having a stent, or their experience in managing patients with a stent.
Experimental: Oncology cohort
Experimental ureteric stent with specially shaped side-holes that prevent stagnation points (i.e., areas of low flow that cause particles to settle and E&B)
Device: Experimental ureteric stent with specially shaped side-holes that prevent stagnation points (i.e., areas of low flow that cause particles to settle and E&B)
Kidney stone patients and Oncology patients admitted to either the University Hospital Southampton (UHS) or University College London Hospital (UCLH) for management of kidney stones or for the management of urine drainage in ureter will have a novel ureteric stent instead of their planned conventional stent. The novel stent will be removed after 4 weeks (kidney stone patients) or 25 weeks (oncology patients). Recruitment to the cohort of oncology patients will only commence once the results for kidney stones patients have been reviewed.
Other: Qualitative interview
Kidney stone patients, Oncology patients and doctors will be interviewed about their experience of having a stent, or their experience in managing patients with a stent.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
To determine rates of stent failure
Time Frame: From enrolment to stent removal (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)

Outcome measure: Stent failure, defined as any of: a): a stent change earlier than planned (oncology only); b) need for additional surgical or radiological intervention; c): kidney failure (evidenced by acute kidney injury (AKI) on blood tests (eGFR or creatinine kidney function tests) and/or worsening hydronephrosis on imaging

Summary method: Frequency and percentage of people experiencing any stent failure
From enrolment to stent removal (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
To assess extent of encrustation and biofilm (E&B)
Time Frame: From enrolment to stent removal (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)

Outcome measure:

  • Cell culturing (CFU counts per ml per bacterial microorganism)
  • Flow study (pressure value): A section of the retrieved stent will be used for flow study. The part will be placed into a larger diameter tube. DI water/Saline is injected using a pump into the inlet of the external tube and pressure sensor is connected to the inlet tube. Pressure readings will be captured per stent.
  • Dwell time

Summary method:

  • Imaging (selected samples of stents will be examined using non-contact, non-destructive SEM (scanning-electron-microscopy) and/or episcopic-differential-interference-contrast (EDIC) microscopy allowing imaging of the surface with the biofilm in-situ and colonisation by bacteria - when needed)
  • Mean and standard deviation or median and quartiles of pressure readings
From enrolment to stent removal (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)
To determine whether the novel stent leads to better clinical outcomes
Time Frame: From enrolment to completion of patient questionnaires 2-3 weeks post surgery 2 (4 weeks for Kidney cohort), 2-3 weeks post surgery 2 (~25 weeks for Oncology cohort)

Outcome measure:

  • Individual component of the primary outcome
  • Urinary symptoms
  • Infections

Summary method:

  • As per primary outcome
  • Frequency and percentage of participants experiencing each symptom
  • Frequency and percentage of people with antibiotic
  • use, readmission, urosepsis, ITU, death; number of infections per unit of time stent is in use
From enrolment to completion of patient questionnaires 2-3 weeks post surgery 2 (4 weeks for Kidney cohort), 2-3 weeks post surgery 2 (~25 weeks for Oncology cohort)
To assess impact of the novel stent on quality of life
Time Frame: Within first month of stent removal for participants (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)

Outcome measure:

Questionnaires at:

  • Baseline
  • While stent is in situ
  • Post-surgery

Summary method:

Appropriate descriptive summaries (e.g., median and quartiles) per timepoint
Within first month of stent removal for participants (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)
To understand patient experience in having the novel ureteric stent inserted and reason for participation in the trial
Time Frame: From enrolment to stent removal (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)

Outcome measure:

30-45-minute Qualitative interviews with Oncology and Kidney stone cohorts

Summary method:

An inductive thematic analysis of interview transcripts
From enrolment to stent removal (4 weeks for Kidney cohort), (25 weeks for Oncology cohort)

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
To assess extent of encrustation and biofilm (E&B)
Time Frame: After surgery 2 for Kidney Stone cohort (4 weeks) and surgery 2 for Oncology patients (25 weeks)

Outcome measure:

Weight: Weighing stents after being removed from body, at the site (theatre room) and prior to packaging for delivery to the University laboratory

Summary method:

Mean and standard deviation or median and quartiles of weights pre- and post-insertion
After surgery 2 for Kidney Stone cohort (4 weeks) and surgery 2 for Oncology patients (25 weeks)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Southampton

Collaborators

University College London Hospitals
University Hospital Southampton NHS Foundation Trust
National Institute for Health Research, United Kingdom

Investigators

  • Principal Investigator: Ali Mosayyebi, University of Southampton

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 6, 2025

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2026

Study Registration Dates

First Submitted

December 4, 2024

First Submitted That Met QC Criteria

February 4, 2025

First Posted (Actual)

February 7, 2025

Study Record Updates

Last Update Posted (Actual)

May 11, 2026

Last Update Submitted That Met QC Criteria

May 6, 2026

Last Verified

August 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 63246

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

To be decided

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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