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NCT Number: NCT07106125

Antibiotics 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

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Key information

Age range

Up to 29 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

University of California, San Francisco

San Francisco, California, 94158, United States

Location contact

Principal Investigator

CONTACT

[email protected]

415-476-3548

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Trimethoprim-Sulfamethoxazole (TMP-SMX)

Drug

Kidney transplant recipients will continue to take TMP-SMX daily from months 6-12 after transplant

Usual Care

Other

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

Primary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. 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

Secondary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. 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

Study contacts

Contact information is provided by the study sponsor or research team.

Principal Investigator

CONTACT

[email protected]

415-476-3548

Sponsors and collaborators

Lead sponsor

University of California, San Francisco

Other

Registry information

Official study title

Trial of Antibiotic Strategies for Kidney Transplant Recipients

Acronym: TASK

Important dates

Study start
2026
Primary completion
2028
Study completion
2029
First posted
Aug 6, 2025
Registry last updated
Oct 31, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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