Letermovir Prophylaxis for Cytomegalovirus in Pediatric Hematopoietic Cell Transplantation

Medicine to Prevent CMV Infection in Kids After Stem Cell Transplant

A
April Rahrig, MD

Primary Investigator

Enrolling By Invitation
2 years - 18 years
All
Phase 3
1 participants needed
2 Locations

Brief description of study

This phase III trial determines whether taking prophylactic letermovir will reduce the likelihood of infection with cytomegalovirus (CMV) in children and adolescents after stem cell transplant. The treatments used to prepare for HCT reduce the body's natural infection-fighting ability and increase the likelihood of an infection with a virus called cytomegalovirus. "Prophylaxis" means to take a drug to prevent a disease or side effect. Letermovir is an antiviral drug that stops cytomegalovirus from multiplying and may prevent cytomegalovirus infection and make the disease less severe.
 
THIS STUDY IS ENROLLING BY INVITATION ONLY - Consistent with most oncology trials, patients are not actively “recruited,” but are screened by their physician for appropriate clinical trial(s) at the time of their routine clinic visit. Occasionally, a patient may be a self-referral or physician referral, but are still screened for appropriate clinical trials at the time of their routine clinic visit. PI and staff may send copies of relevant consent forms to these patients to look over prior to actually consenting or enrolling them. This may take place at the patient's visit at which the consent is presented or the patient's next visit to the outpatient hematology/oncology clinic. 
 
Interested in participating? For more information about this research study or other cancer-related clinical trials at Indiana University Simon Comprehensive Cancer Center (IUSCCC), please contact:
 
IU Clinical Trials Office
Phone: (317) 278-5632

Detailed description of study

Enrolled patients will be added to the single arm of the study and receive letermovir prophylaxis.

ARM A: Patients receive letermovir orally (PO) or intravenously (IV) over 60 minutes once daily (QD) starting on day +1 post-transplant for 14 weeks. Patients undergo collection of blood samples for CMV polymerase chain reaction (PCR) analysis weekly for 14 weeks, every 2 weeks until week 24, week 32, week 40 and week 52.

ARM B (CLOSED TO ACCRUAL 09/29/2025): Patients undergo collection of blood samples for CMV PCR analysis weekly for 14 weeks, every 2 weeks until week 24, week 32, week 40 and week 52.

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: Hematopoietic and Lymphoid Cell Neoplasm, Malignant Solid Neoplasm, Cancer
  • Age: 2 years - 18 years
  • Gender: All

Inclusion Criteria:

  •     >= 2 years and < 18 years at the time of enrollment
  •    Weight must be >= 18 kg. For patients < 12 years of age and expected to receive cyclosporine, weight must be >= 30kg
  •    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)
  •    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 > 15 mL/min/1.73 m^2 and not receiving dialysis
  •    Total bilirubin =< 2.5 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 Criteria:

  •     Expected inability to tolerate oral formulation (e.g., unable swallow whole tablets) of letermovir
  •        Note: Determination of ability to tolerate the oral formulation will be based on a self-assessment or caregiver assessment; eligible subjects and their caregiver will be shown a life size picture of a tablet (or actual tablet) and confirm ability to swallow whole tablet in order to meet study eligibility
  •    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
  •            Lovastatin
  •            Pitavastatin
  •            Rosuvastatin
  •            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

This study investigates the use of an investigational medication to prevent cytomegalovirus (CMV) infection in children and adolescents who have undergone a stem cell transplant. Cytomegalovirus is a virus that can cause infections, especially in people with weakened immune systems. "Prophylaxis" means taking a drug to prevent a disease or side effect. The investigational medication is designed to stop the virus from multiplying, which may help reduce the chance of infection.

Participants in the study will receive the investigational medication either by mouth or through an IV for 14 weeks, starting one day after their transplant. Blood samples will be collected regularly to check for the virus. This is done through a test called polymerase chain reaction (PCR) analysis, which helps detect the presence of the virus in the blood.

  • Who can participate: Children aged 2 to 17 years who are planning to have a stem cell transplant and are CMV sero-positive can participate. Participants must weigh at least 18 kg, and if under 12 years and receiving cyclosporine, they must weigh at least 30 kg. They must have a good performance status and meet certain health criteria.
  • Study details: Participants will take the investigational medication to prevent CMV infection. Blood tests will be done to monitor the virus. A placebo is not used in this study.
Updated on 24 Feb 2026. Study ID: PHO-COG-ACCL1932, 24686
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Interested in the study?

This study is accepting only persons who receive care at a certain clinic or doctor or who are part of an invited group. Questions about this study can be directed to the study team listed in the description or contact your doctor to see if you are eligible.

Accepting Referrals by Invitation Only