Antibiotics for Kidney Transplant Recipients (TASK)

October 29, 2025 updated by: University of California, San Francisco

Trial of Antibiotic Strategies for Kidney Transplant Recipients

The goal of this clinical trial is to learn if a common antibiotic called trimethoprim-sulfamethoxazole (TMP-SMX) can help prevent urinary tract infections (UTIs) in children and young adults who recently had a kidney transplant. Most people take TMP-SMX for about 6 months after getting a kidney transplant. In this study, researchers want to see what happens if people keep taking it for 6 more months.

The main questions this study is asking are:

  • Does TMP-SMX lower the number of UTIs in the first year after transplant?
  • What side effects or problems do participants have while taking TMP-SMX?

Researchers will compare TMP-SMX to a placebo (a look-alike pill that does not contain any medication) to see if TMP-SMX works to prevent UTIs.

Participants will:

  • Take either TMP-SMX or a placebo pill by mouth every day for 6 months
  • Have three visits to touch base with the study team about any issues
  • Complete short monthly online surveys about any symptoms or side effects
  • Share blood and urine test results from their regular transplant clinic visits

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Phase 4

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

  • United States
    • California
      • San Francisco, California, United States, 94158
        • University of California, San Francisco
        • 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

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Must be able to take capsules orally
  • Kidney transplant performed at a UCSF facility within the last 6 months
  • Most recent glomerular filtration rate (GFR) >30 mL/min/1.73 m2
  • Tolerated initial 6 months of post-transplant TMP-SMX (defined as no intentional periods of TMP-SMX cessation in first 6 months after transplant due to hyperkalemia, allergic reaction, or unexpected/excessive neutropenia)
  • Considered "high risk for UTI" after kidney transplant, as defined by one or more of the following: (1) Congenital anomaly of kidney/urinary tract as kidney failure etiology, (2) Diagnosis of neurogenic bladder and/or use of clean intermittent catheterization and/or nightly continuous urinary drainage, (3) Diabetes mellitus (diagnosed either prior to or new-onset after transplant), (4) History of recurrent UTIs as diagnosed by a provider prior to transplant, (5) Occurrence of any UTI in first 6 months after transplant, (6) Delayed graft function (defined as need for dialysis within 7 days of transplant)

Exclusion Criteria:

  • History of intolerance or allergy to trimethoprim (TMP) and/or sulfamethoxazole (SMX)
  • History of UTI due to a TMP-SMX-resistant organism in the first 6 months after transplant
  • Moderate or severe neutropenia (absolute neutrophil count <1,000 cells/μL) on most recent bloodwork available at the time of recruitment
  • Uncontrolled hyperkalemia (serum potassium ≥5.0 mEq/L) on most recent bloodwork available at the time of recruitment
  • Provider-determined/documented need for either continuation or discontinuation of TMP-SMX prophylaxis that would preclude the patient's randomization
  • Current pregnancy
  • Incarcerated individuals/prisoners
  • Inability to provide informed consent or assent, and no legally authorized representative available

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: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Other: Usual Care
Participants will take a placebo from months 6-12 after transplant and continue to receive all standard usual care related to their kidney transplant status
Experimental: Drug
TMP-SMX
Drug: Trimethoprim-Sulfamethoxazole (TMP-SMX)
Kidney transplant recipients will continue to take TMP-SMX daily from months 6-12 after transplant

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Agreement Between Participant Self-Report and Medical Records on Clinical Events (Measured by Cohen's Kappa)
Time Frame: From enrollment to the end of the study drug period (6 months)
The investigators will look at how closely participants' self-reports of events (urinary tract and associated infections, acute kidney injury events, and hospitalizations) match what is identified through their electronic health records. To do this, the investigators will use a statistical tool called Cohen's kappa, which shows how much agreement there is between the two sources.
From enrollment to the end of the study drug period (6 months)
Number of Participants Who Enroll After Screening
Time Frame: Baseline/Study Day 1 (i.e., date that informed consent is signed for those who choose to participate)
The investigators will track how many people decide to join and how many people decline to join the study after completing the screening process.
Baseline/Study Day 1 (i.e., date that informed consent is signed for those who choose to participate)
Medication Adherence Assessed by Self-Report
Time Frame: From enrollment to the end of the study drug period (6 months)
The investigators will ask participants how often they are taking the pills as directed, through monthly surveys and at all study visits.
From enrollment to the end of the study drug period (6 months)
Trial Retention
Time Frame: From enrollment to the end of the study drug period (6 months)
The investigators will keep track of how many participants complete the last study visit
From enrollment to the end of the study drug period (6 months)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Event Rate of All-Cause Hospitalizations by Treatment Arm
Time Frame: From enrollment through the end of the study period (12 months)
The investigators will keep track of when participants are hospitalized, using feedback from participants themselves (for the first 6 months) as well as data from their electronic medical records (for 6 additional months, for a total of 12 months). Event rates will be used to compare outcomes between the treatment (TMP-SMX continuation) and placebo arms.
From enrollment through the end of the study period (12 months)
Urinary Tract Infections by Treatment Arm
Time Frame: From enrollment to the end of the study period (12 months)
The investigators will keep track of when participants report having a urinary tract infection, using feedback from participants themselves (for the first 6 months) as well as data from their electronic medical records (for 6 additional months, for a total of 12 months). Event rates will be used to compare outcomes between the treatment (TMP-SMX continuation) and placebo arms.
From enrollment to the end of the study period (12 months)
Acute Kidney Injury Events by Treatment Arm
Time Frame: From enrollment to the end of the study period (12 months)
The investigators will keep track of when participants report having acute kidney injury events, using feedback from participants themselves (for the first 6 months) as well as data from their electronic medical records (for 6 additional months, for a total of 12 months). Event rates will be used to compare outcomes between the treatment (TMP-SMX continuation) and placebo arms.
From enrollment to the end of the study period (12 months)
Adverse Events by Treatment Arm
Time Frame: From enrollment to the end of the study drug period (6 months)
The investigators will keep track of when participants report side effects and adverse events, using feedback from participants themselves as well as data from their electronic medical records
From enrollment to the end of the study drug period (6 months)

Collaborators and Investigators

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

Sponsor

University of California, San Francisco

Investigators

  • Principal Investigator: Alexandra Bicki, MD, University of California, San Francisco

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 (Estimated)

November 1, 2026

Primary Completion (Estimated)

December 1, 2028

Study Completion (Estimated)

January 1, 2029

Study Registration Dates

First Submitted

July 21, 2025

First Submitted That Met QC Criteria

July 29, 2025

First Posted (Actual)

August 6, 2025

Study Record Updates

Last Update Posted (Estimated)

October 31, 2025

Last Update Submitted That Met QC Criteria

October 29, 2025

Last Verified

October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25-44366

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Due to ethical considerations, the access, distribution, and reuse of the resulting scientific data will not be permitted. The study involves minors and a sample size that may be prone to "small cells" (using the Centers for Medicare and Medicaid definition of <10 individuals with certain characteristics). We will not share individual-participant level data.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

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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