Letermovir to Prevent CMV Infection After Stem Cell Transplant in Children
This study is looking at whether the drug letermovir can prevent a common infection called cytomegalovirus (CMV) in children and adolescents who have had a stem cell transplant. After a stem cell transplant, the body's ability to fight infections is weakened, making CMV infection more likely. Letermovir is an antiviral drug that works by stopping CMV from multiplying. The study will see if taking letermovir reduces the chance of getting a significant CMV infection within 14 weeks after the transplant. You may be able to join if you are between 2 and 18 years old, weigh at least 6 kg, are planning to have a stem cell transplant, and have previously been exposed to CMV.
- Study design
- This is a single-arm study, meaning all 105 participants will receive letermovir. It aims to see if letermovir prevents CMV infection after a stem cell transplant.
- What's involved
- Participants will undergo collection of blood samples and receive letermovir, given either by mouth or intravenously (into a vein).
- Compensation
- Not stated in the trial record.
- Follow-up
- The study will follow participants for clinically significant CMV infection up to 14 weeks post-transplant, and for CMV-free survival up to 24 weeks post-transplant.
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NCT05711667
A Study of the Drug Letermovir as Prevention of Cytomegalovirus Infection After Stem Cell Transplant in Pediatric Patients
Recruiting
PHASE3Ages 2–18InterventionalPreventionChildren's Oncology GroupGovernment-funded
~105 participants
Updated 2026-05-05 on ClinicalTrials.gov
What's tested:Biospecimen CollectionLetermovir
At a glance
Recruiting sites
27 of 29 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Clinically significant cytomegalovirus (CMV) infection
Measured over Up to week 14 post-transplant
Conditions
Where it's being run
29 sites across 20 statesTexas4
Tennessee3
California2
Florida2
Michigan2
Missouri2
Alabama1
Colorado1
Study leadership
- Caitlin W Elgarten · PRINCIPAL_INVESTIGATOR · Children's Oncology Group
Who to contact
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Do you actually qualify for this trial?
Add a private profile and we'll compare every criterion below against your situation — and tell you which ones are met, uncertain, or excluding.
Eligibility criteria
Inclusion
\>= 2 years and \< 18 years at the time of enrollment
Weight must be \>= 6 kg at the time of enrollment
Planned allogeneic HCT (bone marrow, peripheral blood stem cell, or cord blood transplant)
Patient must be CMV sero-positive (i.e., recipient CMV immunoglobulin G positive)
Note: If a patient has hypogammaglobulinemia but has previously been documented as CMV sero-positive, that is acceptable for study inclusion. For all patients already confirmed to be CMV IgG seropositive, repeat testing is not required within 7 days prior to enrollment. However, the laboratory data determining eligibility must be available in the patient's medical/research record for verification
Patient is eligible for entry only if it is feasible for plasma CMV PCR testing to be sent and resulted within the protocol mandated time period
Reminder: To limit the likelihood of positive plasma CMV PCR post-enrollment and prior to start of study treatment period, it is recommended that patient enrollment proceed after patients start their transplant preparative regimen
Patient must have a performance status corresponding to Lansky/Karnofsky scores \> 50
Note: Use Lansky for patients =\< 16 years of age and Karnofsky for patients \> 16 years of age. For further reference, see performance status scales scoring under the standard sections for protocols among protocol reference materials provided on the Children's Oncology Group (COG) member website: https://members.childrensoncologygroup.org/prot/reference\_materials.asp
Estimated glomerular filtration rate \> 10 mL/min/1.73 m\^2 and not receiving dialysis
Direct bilirubin =\< 2 mg/dL and serum glutamate-pyruvate transaminase (SPGT) (alanine transaminase \[ALT\]) =\<10 x upper limit of normal (ULN) for age
Note: For the purpose of this study, the ULN for SGPT (ALT) has been set to the value of 45 U/L
Exclusion
Expected inability to tolerate oral formulation of letermovir
Hypersensitivity to letermovir or any component of the formulation
History of CMV end organ disease within 6 months (180 days) prior to enrollment
Note: CMV end organ disease based on proposed definitions by Ljungman et al. and inclusive of proven, probable or possible disease
Receipt of prior allogeneic HCT within one year of study enrollment
Planned prophylactic administration of other anti-CMV medications or cellular products during the study, including:
High dose acyclovir (defined as doses \>= 1500 mg/m\^2 IV or \>= 3200 mg oral (patients \>= 40 kg) or \>= 2400 mg/m\^2 (patients \< 40 kg) per day)
High dose valacyclovir (defined as doses \>= 3000 mg/day in patients \> 20 kg)
Foscarnet
Ganciclovir
Valganciclovir
CMV-directed cytotoxic T lymphocytes
Planned receipt of the following contraindicated medications during the study treatment period; contraindicated medications must be discontinued at least 14 days prior to Day +1
Contraindicated medications for all patients:
Pimozide
Ergot alkaloids
Contraindicated medications for patients planned to receive cyclosporine:
Bosentan
Pitavastatin
Simvastatin
Female patients who are pregnant since fetal toxicities and teratogenic effects have been noted in certain animal reproduction studies with letermovir. A pregnancy test is required for female patients of childbearing potential
Lactating females who plan to breastfeed their infants
Sexually active female patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their letermovir treatment and through at least 4 weeks after the last dose of letermovir.
Note: No contraception measures are needed specifically during letermovir treatment for male trial participants who have pregnant or non-pregnant female partner(s) of reproductive potential. Contraception measures may be required for other aspects of the HCT procedure.
All patients and/or their parents or legal guardians must sign a written informed consent
All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met
What this trial measures
- Clinically significant cytomegalovirus (CMV) infectionUp to week 14 post-transplant
Clinically significant CMV is defined as the first of (1) initiation of anti-CMV preemptive therapy for documented CMV DNAemia or (2) onset of CMV end-organ disease. Will estimate the cumulative incidence of clinically significant CMV at 14-weeks post-transplant and will report the corresponding 95% confidence interval.