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Letermovir to prevent CMV in children and adolescents after kidney transplant

A Phase 1, Open-label, Single-arm Study to Evaluate the Pharmacokinetics and Safety of Letermovir in Pediatric Kidney Transplant (KT) Recipients Less Than 18 Years of Age and Weighing Less Than 40 Kilograms

Phase 1 Interventional Merck Sharp & Dohme LLC · NCT07199465

This study will test whether the antiviral letermovir can safely prevent cytomegalovirus (CMV) in children and adolescents under 40 kg who recently received a kidney transplant.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment40 (estimated)
AgesN/A to 17 Years
SexAll
SponsorMerck Sharp & Dohme LLC Industry-sponsored
Locations14 sites (Birmingham, Alabama and 13 other locations)
Trial IDNCT07199465 on ClinicalTrials.gov

What this trial studies

This Phase 1 trial gives letermovir to children and adolescents who are 4 to 52 weeks after a kidney transplant to characterize how the drug behaves in their bodies and to collect safety and tolerability data. Participants must weigh between 2.5 and <40 kg, have stable kidney function, and have undetectable CMV DNA before enrollment. Dosing is given orally as tablets or pellets, with pellets allowable via gastrostomy or nasogastric tube, and includes an intensive pharmacokinetics (IPK) sampling period. The primary focus is pharmacokinetics and short-term safety rather than efficacy outcomes.

Who should consider this trial

Good fit: Ideal candidates are children and adolescents 4 to 52 weeks after a primary or secondary kidney transplant, weighing ≥2.5 and <40 kg, with stable graft function and undetectable CMV DNA who can take oral tablets or pellets (or pellets via feeding tube).

Not a fit: Patients with active CMV infection, detectable CMV DNA, malabsorptive conditions or ongoing vomiting/diarrhea, unstable kidney function, or those outside the specified weight or post-transplant time windows are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, letermovir could provide a safer, effective option to prevent CMV infections after pediatric kidney transplant, potentially reducing CMV-related illness and complications.

How similar studies have performed: Letermovir has demonstrated effectiveness for CMV prevention in adult hematopoietic stem cell transplant populations, but its use for pediatric kidney transplant prophylaxis is largely untested.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

* Is a recipient of a primary or secondary allograft kidney
* Is at least 4 weeks posttransplant and not more than 52 weeks posttransplant at the time of enrollment (Day 1) and is being managed per local standard of care
* Has stable kidney function posttransplant
* Has undetectable CMV deoxyribonucleic acid (DNA) from a plasma or whole blood sample collected within 14 days prior to enrollment
* Must be able to take (as assessed by the investigator) letermovir tablets or oral pellets by mouth, or via gastrostomy or nasogastric tube (oral pellets only)
* Does not have a condition that may interfere with the absorption of oral medication (e.g., vomiting, diarrhea, or a malabsorptive condition) from the day of enrollment (Day 1) until the intensive pharmacokinetics (IPK) sampling is completed
* Weighs ≥2.5 and \<40 kg at enrollment (Day 1)

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

* Has CMV disease or suspected CMV disease between screening and enrollment
* Is on dialysis or plasmapheresis at the time of enrollment
* Has evidence of CMV viremia at any time from screening until the time of enrollment
* Has Child-Pugh B or C hepatic insufficiency within 14 days before enrollment
* Is a multi-organ transplant recipient (e.g., kidney-pancreas)
* Has any uncontrolled infection on the day of enrollment
* Requires mechanical ventilation, or is hemodynamically unstable, at the time of enrollment
* Has received or is receiving protocol-specified prohibited medications

Where this trial is running

Birmingham, Alabama and 13 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Cytomegalovirus Prophylaxis
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.