Multicenter Clinical Trial of ST-02 for Ablation of Upper Tract Urothelial Carcinoma

September 8, 2025 updated by: Peter Black, University of British Columbia

A Phase 2/3 Multicenter Trial Evaluating the Safety and Efficacy of ST-02 (Mucoadhesive Gemcitabine Suspension) on Ablation of Urothelial Carcinomas in the Upper Urinary Tract

The goal of this prospective clinical trial is to investigate the safety and efficacy of ST-02 (mucoadhesive gemcitabine suspension for pyelocaliceal instillation) to treat Upper Tract Urothelial Carcinoma (UTUC) in participants who have a low-grade tumor.

The main questions this study aims to answer are:

  1. Can ST-02 effectively eradicate UTUC by 3 months?
  2. Is ST-02 safe for patients with UTUC?

Participants in this study will receive ST-02, a new formulation with gemcitabine once weekly for six weeks. Gemcitabine is known to be an effective drug in treating urothelial carcinoma. This new formulation will be instilled directly into the upper urinary tract (renal pelvis) and will allow the chemotherapeutic to work locally for an extended period of time. The administration process will be retrograde (via a small catheter inserted up into the kidney, under anesthesia) or antegrade (via a nephrostomy, in the clinic) once weekly for six weeks. Safety and efficacy will be monitored for up to a year after the initial response assessment.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This study is a prospective, multicenter, single-arm, open-label clinical trial assessing the safety and efficacy of ST-02 (mucoadhesive gemcitabine suspension for pyelocaliceal instillation) to chemo-ablate low-grade urothelial carcinoma of the upper urinary tract.

Participants with biopsy confirmed low-grade (LG) upper tract urothelial carcinoma (UTUC) and a tumor of 5 to 15 mm will receive 6 weekly instillations of ST-02.

The primary objective is to evaluate complete response (CR) at 3 months from the first instillation during the primary tumor evaluation (PTE) visit. This is done by ureteroscopy, and cytology, with or without biopsy if a tumor remains. If the participant presents as a CR, they will receive their first maintenance instillation of ST-02. Endoscopic monitoring of the upper tract with ureteroscopy for responders will be performed every 3 months for up to 12 months after CR, and the patient will receive a single instillation of ST-02 if no recurrence is noted each time.

Participants who do not have a CR will be treated by their physician with the standard of care, such as biopsy and laser ablation, and with any additional surgical procedure or treatment as deemed necessary by the Principal Investigator (PI).

The first stage of the trial will enroll 30 patients. If there are 8 or fewer CR among these 30 participants, the study will be stopped. Otherwise, an additional 40 participants will be accrued into phase 3, resulting in a total sample size of 70.

The durability of response, event-free survival, safety, and other outcomes will also be measured.

Study Type

Interventional

Enrollment (Estimated)

70

Phase

  • Phase 2
  • Phase 3

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 Locations

  • Canada
    • British Columbia
      • Vancouver, British Columbia, Canada
        • Recruiting
        • Vancouver Prostate Centre
        • Principal Investigator:
          • Peter Black
        • Contact:
          • Genevive Moreau
        • Sub-Investigator:
          • Marie-Pier Marie-Pier St-Laurent
        • Sub-Investigator:
          • Miles Mannas
    • Manitoba
      • Winnipeg, Manitoba, Canada, R3P 2S8
        • Recruiting
        • Men's Health Clinic
        • Contact:
        • Principal Investigator:
          • Jasmir Nayak, MD
    • Nova Scotia
      • Halifax, Nova Scotia, Canada
        • Recruiting
        • Centre of Applied Urology Research, Nova Scotia Health Authority
        • Contact:
        • Principal Investigator:
          • Ricardo Rendon
    • Ontario
      • Toronto, Ontario, Canada
        • Recruiting
        • UHN - Princess Margaret Cancer Centre
        • Contact:
        • Principal Investigator:
          • Girish Kulkarni

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:

  • Adult (≥ 18 years) male or female
  • Primary or recurrent low-grade (LG), noninvasive (Ta) Upper Tract Urothelial Carcinoma (UTUC) in the renal pelvis, infundibulum, and/or calyces, based on ureteroscopy, biopsy and cytology performed within 8 weeks prior to the Screening Visit
  • At least 1 measurable papillary tumor measuring 5-15 mm
  • Low grade tumor(s) in the ipsilateral ureter. Every attempt should be made to ablate this tumor completely, but residual ipsilateral ureteral tumor is not an exclusion criterion.
  • Prior fully ablated low grade bladder tumor(s), without the need for intravesical therapy except for single-dose chemotherapy
  • A life expectancy of greater than 12 months
  • No active untreated urinary tract infection (UTI) as confirmed by urine culture or urinalysis
  • Women of Child bearing potential (WoCBP) and Males who have a WoCBP partner require a negative pregnancy test at the Screening visit and must use two acceptable contraceptives methods until six months post-treatment
  • All sexually active males must agree to use a condom during intercourse, for at least 48 h after each instillation

Exclusion Criteria:

  • Have received Bacillus Calmette - Guerin (BCG) treatment for UTUC within 6 weeks prior to Visit 1
  • Pregnant (positive urine pregnancy test), planning pregnancy during trial, breast-feeding, or of childbearing potential without reliable contraception
  • Unresolved infection requiring active treatment with systemic antimicrobial drugs
  • History of high-grade non-muscle invasive bladder cancer within the past 6 months
  • History of muscle-invasive bladder cancer during the past 2 years
  • Actively being treated or intend to be treated with intravesical or systemic chemotherapy during the duration of the trial
  • Urinary obstruction in the ipsilateral Upper Urinary Tract (UUT)
  • Any contraindicated to gemcitabine or sensitivity to gemcitabine or any of the ST-02 ingredients
  • Currently receiving another investigational agent or involved in a clinical trial with an investigational product within the past 30 days prior to Visit 1
  • Active hepatitis B (chronic or acute) or active hepatitis C infection

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: ST-02
ST-02 is a new gemcitabine formulation for instillation into the upper urinary tract. Eligible participants will be enrolled and receive ST-02 once weekly for six weeks in a retrograde or antegrade fashion at the discretion of the treating urologist.
Drug: ST-02
ST-02 drug instillation into the upper urinary tract (renal pelvis)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Complete Response (CR) rate at the Primary Tumor Evaluation (PTE) visit
Time Frame: 3 months
To evaluate the tumor ablative effect (CR after 3 months) of six instillations of ST-02 in the upper urinary tract of participants with UTUC.
3 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Durable efficacy
Time Frame: 12 months after CR
To evaluate the durability of tumor ablative effect 12 months after CR in participants who demonstrated complete response at 3 months after instillation of six doses of ST-02
12 months after CR
Objective Response Rate (ORR)
Time Frame: 3 months
To evaluate the objective response rate after treatment with ST-02, defined as proportion of participants with Complete Response (CR) or Partial Response (PR) at the PTE Visit
3 months
Event-Free Survival (EFS)
Time Frame: 15 months
To evaluate the event-free survival after treatment with ST-02
15 months
Number of adverse event
Time Frame: 15 months
To evaluate the safety and tolerability of instillation of ST-02 in participants with UTUC
15 months
Peak Plasma Concentration (Cmax)
Time Frame: 24 hours
To assess the peak concentration of gemcitabine in urine and plasma at 0, 1, 2, 4 and 24 hours after instillation (10 patients, phase 2 only)
24 hours
Pharmacokinetics (Tmax)
Time Frame: 24 hours
To assess the time to maximal concentration of gemcitabine in urine and plasma at 0, 1, 2, 4 and 24 hours after instillation (10 patients, phase 2 only)
24 hours
Rate of invasive surgery
Time Frame: 15 months
To evaluate the rate of nephroureterectomy following instillation of ST-02
15 months
Clinical impact of PR in not endoscopically resectable UTUC
Time Frame: 3 months
To evaluate the proportion of participants with PR whose tumors were considered not endoscopically resectable at baseline but are endoscopically resectable after treatment with ST-02
3 months

Collaborators and Investigators

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

Sponsor

University of British Columbia

Investigators

  • Principal Investigator: Peter Black, Dr., Vancouver Prostate Centre

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)

June 19, 2024

Primary Completion (Estimated)

April 1, 2026

Study Completion (Estimated)

April 1, 2026

Study Registration Dates

First Submitted

October 27, 2023

First Submitted That Met QC Criteria

November 7, 2023

First Posted (Actual)

November 9, 2023

Study Record Updates

Last Update Posted (Estimated)

September 15, 2025

Last Update Submitted That Met QC Criteria

September 8, 2025

Last Verified

August 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • H23-02476

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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