CompletedPhase 3

Extension of Letermovir (LET) From Day 100 to Day 200 Post-transplant for the Prevention of Cytomegalovirus (CMV) Infection in Hematopoietic Stem Cell Transplant (HSCT) Participants (MK-8228-040)

United States, France, Germany220 participantsStarted 2019-06-21

Plain-language summary

The purpose of this study was to evaluate the safety and efficacy of letermovir (LET) versus placebo when cytomegalovirus (CMV) prophylaxis was extended from 100 days to 200 days post-transplant in CMV seropositive participants who received an allogenic hematopoietic stem cell transplant (HSCT). It was hypothesized that LET is superior to placebo in the prevention of clinically-significant CMV infection when LET prophylaxis is extended from 100 to 200 days.

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * have documented positive CMV serostatus (CMV immunoglobulin G \[IgG\] seropositive) for recipient (R+) at the time of transplant * has a history of allogeneic HSCT (bone marrow, peripheral blood stem cell, or cord blood transplant) within \~100 days prior to randomization * has undetectable CMV deoxyribonucleic acid (DNA) or detectable/not quantifiable CMV DNA from a plasma sample collected within 14 days prior to randomization * has received LET as primary prophylaxis that started within 28 days of HSCT and continued through Week 14 post-transplant (± 1 week) prior to randomization * is at high risk of CMV disease, defined as meeting one or more of the following criteria: * has a related donor with at least 1 mismatch at 1 of the specified 3 human leukocyte antigen (HLA) gene loci (HLA-A, B, or DR) * has an unrelated donor with at least one mismatch at one of the specified four HLA gene loci (HLA-A, B, C, and DRB1) * has a haploidentical donor * has umbilical cord blood as the stem-cell source * has ex-vivo T-cell-depleted grafts * has received anti-thymocyte globulin * has received alemtuzumab * has graft versus host disease (GVHD) or other conditions, requiring the use of systemic prednisone (or equivalent) at a dose of ≥1 mg/kg of body weight per day within 6 weeks of randomization * for female participants, is not pregnant or breastfeeding, and is either not a woman of childbearing potential (WOCBP) or is a WOBCP who agrees to use acceptable contra…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1This trial extended letermovir use from around day 100 all the way to day 200 after transplant — based on what this study found, would continuing letermovir beyond the standard 100 days make sense for my specific situation?
2Since this was a Phase 3 trial that has already completed, has my doctor seen the results, and do they suggest the extended letermovir course meaningfully reduced serious CMV infections in the day 100 to day 200 window?
3CMV infection risk seems to be a real concern even after the first 100 days post-transplant — how does my own CMV status and my donor's CMV status affect whether I might benefit from a longer course of letermovir like the one studied here?
4Taking a preventive antiviral medication for an extra 100 days is a significant commitment — what side effects or drug interactions did this trial track, and how might those apply to the other medications I'd be on after my transplant?
5Is extended letermovir prophylaxis something my transplant center already offers based on evidence like this trial, or would it be considered outside the current standard of care for someone in my position?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Percentage of Participants With Clinically Significant CMV Infection From Week 14 (~100 Days) Post-transplant Through Week 28 (~200 Days) Post-transplant

Timeframe: From Week 14 post-transplant to Week 28 post-transplant (approximately 14 weeks)

Trial details

NCT IDNCT03930615

SponsorMerck Sharp & Dohme LLC

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2021-10-27

Results submitted2022-10-05

View on ClinicalTrials.gov More Cytomegalovirus Infection trials