Letermovir (MK-8228) Versus Placebo in the Prevention of Clinically-Significant Cytomegalovirus (CMV) Infection in Adult, CMV-Seropositive Allogeneic Hematopoietic Stem Cell Transplant Recipients (MK-8228-001)

The study evaluated the efficacy and safety of letermovir (MK-8228) for the prevention of clinically-significant CMV infection in adult, CMV-seropositive recipients of allogeneic hematopoietic stem cell transplant (HSCT). The hypothesis being tested was that MK-8228 is superior to placebo in the prevention of clinically-significant CMV infection through Week 24 post-transplant.


Eligibility Criteria:
Inclusion Criteria:

* Has documented seropositivity for CMV within 1 year before hematopoietic stem cell transplant (HSCT)
* Receiving first allogeneic HSCT (bone marrow, peripheral blood stem cell, or cord blood transplant)
* Female or male participant who is not of reproductive potential, or, if of reproductive potential, agrees to true abstinence or to use (or have their partner use) 2 acceptable methods of birth control from the time of consent through 90 days after the last dose of study drug
* Able to read, understand, and complete questionnaires and diaries

Exclusion Criteria:

* Received a previous allogeneic HSCT (previous autologous HSCT is acceptable)
* History of CMV end-organ disease within 6 months before randomization
* Has evidence of CMV viremia (if tested) at any time from either signing of the Informed Consent Form or the HSCT procedure, whichever is earlier, until the time of randomization.
* Received the following within 7 days before screening or plans to receive during the study: ganciclovir, valganciclovir, foscarnet, acyclovir, valacyclovir, or famciclovir
* Received the following within 30 days before screening or plan to receive during the study: cidofovir, CMV hyper-immune globulin, any investigational CMV antiviral agent or biological therapy
* Has suspected or known hypersensitivity to ingredients of MK-8228 (letermovir) formulations
* Has severe hepatic insufficiency within 5 days before randomization
* Has end-stage renal impairment
* Has an uncontrolled infection on the day of randomization
* Requires mechanical ventilation or is hemodynamically unstable at the time of randomization
* Has documented positive results for human immunodeficiency virus (HIV) antibody, hepatitis C virus (HCV) antibody with detectable HCV ribonucleic acid, or hepatitis B surface antigen (HBsAg) within 90 days before randomization
* Has active solid tumor malignancies with the exception of localized basal cell or squamous cell skin cancer or the condition under treatment (for example, lymphoma)
* Is pregnant or expecting to conceive, is breastfeeding, or plans to breastfeed from the time of consent through 90 days after the last dose of study drug
* Is expecting to donate eggs or sperm from the time of consent through 90 days after the last dose of study drug
* Has participated in a study with an unapproved investigational compound (monoclonal antibodies are excepted) or device within 28 days of the first dose of study drug
* Has previously participated in a MK-8228 (letermovir) study
* Has, is, or is planning (during the study) to participate in any study involving administration of a CMV vaccine or another CMV investigational agent
* Is a user of recreational or illicit drugs or has a recent history (\<=1 year) of drug or alcohol abuse or dependence