Letermovir for Antiviral Prophylaxis

Recruiting at 1 trial location

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Age: < 18

Sex: Any

Trial Phase: Phase 1

Sponsor: Merck Sharp & Dohme LLC

Must be taking: Letermovir

Must not be taking: Prohibited medications

Disqualifiers: CMV disease, Dialysis, Multi-organ transplant, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 1 week

40 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests letermovir, a medicine that might prevent cytomegalovirus (CMV) in children and teens who have undergone a kidney transplant. Researchers aim to observe how the body processes letermovir over time and assess its safety and tolerability. The trial includes participants who have had a kidney transplant for at least four weeks but no more than 52 weeks and weigh less than 88.2 pounds. Participants must not show signs of CMV and need stable kidney function to join. As a Phase 1 trial, this research focuses on understanding how letermovir works in people, offering participants the chance to be among the first to receive this potentially groundbreaking treatment.

Will I have to stop taking my current medications?

The trial information does not specify if you need to stop taking your current medications, but it mentions that certain medications are prohibited. It's best to discuss your current medications with the trial team to see if they are allowed.

Is there any evidence suggesting that letermovir is likely to be safe for humans?

Research has shown that letermovir is generally well-tolerated. In a study with adult kidney transplant patients, letermovir proved safe and effective in preventing CMV infections. Another study confirmed its minimal side effects and efficacy in preventing CMV in transplant patients.

While less information exists about its use in children, real-life data from a smaller group of high-risk pediatric patients suggest that letermovir is safe for them. However, this trial remains in its early stages, and researchers continue to gather more information about its safety in children and teenagers. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Unlike the standard antiviral treatments for transplant patients, Letermovir is unique because it specifically targets the CMV (cytomegalovirus) terminase complex, which is a different approach compared to drugs like ganciclovir or valganciclovir that inhibit viral DNA polymerase. This targeted mechanism could mean fewer side effects and lower toxicity, which is a big deal for patients who need long-term antiviral prophylaxis. Researchers are excited because Letermovir's weight-banded dosing might allow for more personalized and effective preventive care, potentially improving outcomes for transplant recipients by reducing the risk of CMV infection without the harsh side effects of current treatments.

What evidence suggests that letermovir might be an effective treatment for preventing CMV in children and adolescents post-kidney transplant?

Research has shown that letermovir, which participants in this trial will receive, effectively prevents cytomegalovirus (CMV) infections in transplant patients. Studies have found that letermovir significantly reduces CMV infections compared to a placebo. Patients generally tolerate it well, and it is considered safe. Letermovir has successfully prevented the virus from appearing in the blood of transplant recipients, with few side effects. Additionally, real-world studies confirm its effectiveness and safety in teenagers undergoing transplants. ^{5 6 7 8 9}

Who Is on the Research Team?

Medical Director

Principal Investigator

Merck Sharp & Dohme LLC

Are You a Good Fit for This Trial?

This trial is for children and adolescents who have received a kidney transplant, weigh between 2.5 to less than 40 kg, and are at least 4 weeks but no more than one year post-transplant with stable kidney function. They must not have detectable CMV DNA in their blood and should be able to take letermovir orally or through a tube without conditions that affect absorption.

Inclusion Criteria

I have received a kidney transplant.

I had a transplant between 4 weeks and 52 weeks ago.

My kidney function is stable after a transplant.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive letermovir for 7 consecutive days post-kidney transplant

1 week

Daily visits for dosing and monitoring

Follow-up

Participants are monitored for safety and effectiveness after treatment

3 weeks

Regular visits for safety assessments

What Are the Treatments Tested in This Trial?

Interventions

• Letermovir

Trial Overview The study tests Letermovir's effects on preventing cytomegalovirus (CMV) after a kidney transplant in young patients. It aims to understand how the body processes the drug over time, its safety, and how well participants can tolerate it.

How Is the Trial Designed?

Group I: Weight-banded letermovir dosing Experimental Treatment 1 Intervention

Participants who are between 4 and 52 weeks post-KT will receive letermovir for 7 consecutive days.

Who Is Running the Clinical Trial?

Merck Sharp & Dohme LLC

Lead Sponsor

Trials

4,096

Recruited

5,232,000+

Chirfi Guindo

Merck Sharp & Dohme LLC

Chief Marketing Officer since 2022

Degree in Engineering from Ecole Centrale de Paris, MBA from New York University Stern School of Business

Robert M. Davis

Merck Sharp & Dohme LLC

Chief Executive Officer since 2021

JD from Northwestern University Pritzker School of Law, MBA from Northwestern University Kellogg Graduate School of Management, Bachelor's in Finance from Miami University

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9879759/

Real-World Outcomes Associated With Letermovir Use for ... A phase 3 trial showed that letermovir primary prophylaxis (PP) reduced clinically significant CMV infection (cs-CMVi) at 24 weeks post-HCT compared to placebo ...

2. sciencedirect.com sciencedirect.com/science/article/abs/pii/S1053249825022570

Tolerability and Clinical Efficacy of Letermovir for Primary ... 32 patients completed 3 or 6 months of LET prophylaxis. There were no episodes of neutropenia while on LET compared to 15% (30/204) in the ...

3. nejm.org nejm.org/doi/full/10.1056/NEJMoa1706640

Letermovir Prophylaxis for Cytomegalovirus in ... Letermovir at a dose of 240 mg per day was highly effective in preventing CMV viremia after engraftment in transplant recipients and had little toxicity.

4. frontiersin.org frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2025.1558637/full

Real-world efficacy and safety of letermovir versus ... In this single-center real-world study, letermovir exhibited a favourable efficacy and safety profile for CMV prophylaxis in adolescent patients undergoing ...

5. astctjournal.org astctjournal.org/article/S2666-6367(24)00434-2/fulltext

Impact of Primary Letermovir Prophylaxis Versus ... In this study, LTV prophylaxis was associated with a decreased total cost of care for HR CMV patients through day+180. Specifically, reductions ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/38615067/

a multicenter, open-label, noncomparative Phase 3 study Letermovir was generally well tolerated, and the data support its use for the prevention of CMV disease/infection in adult Japanese KTRs.

7. jamanetwork.com jamanetwork.com/journals/jama/fullarticle/2805945

Letermovir vs Valganciclovir for Prophylaxis of ... This randomized clinical trial compares the efficacy and safety of letermovir vs valganciclovir prophylaxis for cytomegalovirus (CMV) ...

8. sciencedirect.com sciencedirect.com/science/article/abs/pii/S1600613525028503

Impact of kidney function on 200 days of antiviral ... The efficacy and safety of 200 days valganciclovir cytomegalovirus prophylaxis in high-risk kidney transplant recipients. Am J Transplant.

9. tp.amegroups.org tp.amegroups.org/article/view/142301/html

Real-life data on the efficacy and safety of letermovir for ... Real-life data on the efficacy and safety of letermovir for cytomegalovirus prophylaxis in high-risk pediatric patients: a single-center analysis.