TEAEs will be defined as those with a start date on or after the first dose of study treatment, or with a start date before the date of first dose of study treatment but increasing in severity after the first dose of study treatment. An SAE is any untoward medical occurrence or effect that at any dose results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability / incapacity, is a congenital anomaly / birth defect or is medically important due to other reasons than the above-mentioned criteria. AESIs is defined as any adverse event of special interest.

Vital signs will include temperature, arterial blood pressure (systolic and diastolic) and pulse. Any change in vital signs assessments which will be deemed clinically significant by the investigator will be reported.

Clinical laboratory parameters will include chemistry, hematology, and urinalysis. Any clinical laboratory abnormalities which will be deemed clinically significant by the investigator will be recorded.

12-lead ECG will be evaluated. Any ECG assessments which will be deemed clinically significant by the investigator will be reported.

Participants discontinuing the study drug treatment and the study will be reported.

Cmax of maribavir will be evaluated.

Tmax of maribavir will be evaluated.

Cmin of maribavir will be evaluated.

AUC0-tau of maribavir will be evaluated.

t1/2 of maribavir will be evaluated.

Lambdaz of maribavir will be evaluated.

Vz/F of maribavir will be evaluated.

CL/F of maribavir will be evaluated.

An AE is any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product and that does not necessarily be considered related to investigational product. SAE is any untoward medical occurrence (whether considered related to investigational product or not) that at any dose results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital abnormality or birth defect, or is an important medical event.

The confirmed viremia clearance was defined as a plasma CMV DNA concentration below the lower limit of quantification (LLOQ) (that is \[i.e.\], less than \[\<\] 34.5 international units per milliliter \[IU/mL\]) when assessed by the COBAS® 8800/COBAS® CMV Test, in two consecutive post-baseline samples, separated by at least 5 days. To be considered a responder for the primary endpoint, the participant must have received exclusively study-assigned treatment (regardless of whether study-assigned treatment was completed).

A TEAEs was defined as any event emerging or manifesting at or after the initiation of treatment with an investigational product or medicinal product or any existing event that worsened in either intensity or frequency following exposure to the investigational product or medicinal product. An SAE was any untoward medical occurrence or effect that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability / incapacity, was a congenital anomaly / birth defect or was medically important due to other reasons than the above mentioned criteria.

The number of participants with TEAEs leading to maribavir study treatment discontinuation (including treatment interruption or withdrawal) were reported.

Vital sign assessments included blood pressure, pulse, respiratory rate and body temperature. Any clinically meaningful change in vital signs which were deemed clinically significant by the investigator were reported.

Physical examination included assessments of the head, eyes, ears, nose, throat, neck, lymph nodes, and the cardiovascular, dermatological, musculoskeletal, respiratory, gastrointestinal, genitourinary, and neurological systems. Any clinically meaningful change in physical examination which were deemed clinically significant by the investigator were reported.

Clinical laboratory parameters included evaluations of hematology, chemistry, urinalysis. Any clinically meaningful change in clinical laboratory parameters which were deemed clinically significant by the investigator were reported.

12-lead ECG were evaluated. Any change in ECG assessments which are deemed clinically meaningful by the investigator were reported.

Immunosuppressant drug concentration testing was solely for participants who received immunosuppressive therapy with tacrolimus, cyclosporine, or everolimus. The number of participants with an increased level of at least one immunosuppressant drug was reported.

New onset of acute or chronic GVHD assessed as TEAEs, and graft rejection, or graft loss assessed were reported.

Confirmed CMV viremia clearance is defined as plasma CMV DNA concentrations less than lower limit of quantification (LLOQ; i.e. \<137 International units per milliliter \[IU/mL\]), when assessed by COBAS® AmpliPrep/COBAS® TaqMan® CMV Test in 2 consecutive post baseline samples separated by at least 5 days. To be considered a responder for the primary endpoint, the participant must have received exclusively study-assigned treatment (regardless of whether study-assigned treatment was completed).

Confirmed CMV viremia clearance was defined as plasma CMV DNA concentration less than (\<) lower limit of quantification (LLOQ) that is, \<137 International Units per milliliter (IU/mL) when assessed by COBAS® AmpliPrep/COBAS® TaqMan® CMV Test in 2 consecutive postbaseline samples, separated by at least 5 days. Percentage of participants with confirmed CMV viremia clearance at end of study Week 8 regardless of whether either study-assigned treatment was discontinued before the end of the stipulated 8 weeks of therapy, and could not have received alternative anti-CMV treatment were reported.

Blood samples were collected at the study sites, processed to plasma aliquots, and sent to the central laboratory for quantitative CMV DNA polymerase chain reaction (PCR) testing. Plasma samples were assayed for CMV concentration using a qualified PCR method. This method was linear over 200-100,000 viral copies/mL with a lower limit of quantification (LLOQ) of 200 copies/mL. Results below LLOQ were considered undetectable. Confirmed undetectable plasma CMV DNA within 6 weeks was defined as 2 consecutive post-baseline, on-treatment undetectable results separated by \>/= 5 days (assessed by the central laboratory). Samples were collected on Days 1 and 8, weekly during Weeks 2-6, and once in Weeks 8, 10, 12, 16, 20, 24 (treatment) and Weeks 1, 4, 8, 12 (follow-up). Permissible assessment windows were: Days 8-15 +/- 1 day; Weeks 3-4 +/- 2 days; Weeks 5-6 +/- 3 days; Weeks 8-12 +/- 4 days; Weeks 16-24 +/- 7 days (treatment) and Weeks 1-4 +/- 2 days; Weeks 8-12 +/- 4 days (follow-up).

Treatment-emergent adverse events are those events that occurred on or after study drug administration through 7 days after the last dose of study drug, or are events that occurred prior to study drug administration and recurred with increased severity after taking study drug through 7 days after the last dose of study drug.

Cmax is the maximum observed plasma concentration of digoxin.

Cmax is the maximum observed plasma concentration of dextromethorphan.

Cmax is the maximum observed plasma concentration of dextrorphan, the metabolite of dextromethorphan.

Tmax is the time to reach the maximum observed drug concentration in plasma during a dosing interval.

Tmax is the time to reach the maximum observed drug concentration in plasma during a dosing interval.

Tmax is the time to reach the maximum observed drug concentration in plasma during a dosing interval.

Tmax is the time to reach the maximum observed drug concentration in plasma during a dosing interval.

AUC0-infinity is the area under the plasma concentration versus time curve extrapolated to infinity, calculated using the observed value of the last non-zero concentration.

AUC0-infinity is the area under the plasma concentration versus time curve extrapolated to infinity, calculated using the observed value of the last non-zero concentration.

AUC0-infinity is the area under the plasma concentration versus time curve extrapolated to infinity, calculated using the observed value of the last non-zero concentration.

AUClast is the area under the plasma concentration versus time curve from the time of dosing to the last measurable concentration.

AUClast is the area under the plasma concentration versus time curve from the time of dosing to the last measurable concentration.

AUClast is the area under the plasma concentration versus time curve from the time of dosing to the last measurable concentration.

AUClast parent/metabolite ratio is the ratio of AUClast for dextromethorphan over AUClast for dextrorphan.

AUC0-infinity parent/metabolite ratio is the ratio of AUC0-infinity for dextromethorphan over AUC0-infinity for dextrorphan.

AUCtau is the area under the plasma concentration versus time curve from the time zero to the end of the dosing interval at steady-state.

Lambda z is the first-order rate constant associated with the terminal (log-linear) portion of the plasma concentration versus time curve, determined as the negative slope of the terminal log-linear phase of the curve.

Lambda z is the first-order rate constant associated with the terminal (log-linear) portion of the plasma concentration versus time curve, determined as the negative slope of the terminal log-linear phase of the curve.

Lambda z is the first-order rate constant associated with the terminal (log-linear) portion of the plasma concentration versus time curve, determined as the negative slope of the terminal log-linear phase of the curve.

Terminal half-life (t1/2) is the time in hours required for the concentration of the drug to reach half of its original value.

Terminal half-life (t1/2) is the time in hours required for the concentration of the drug to reach half of its original value.

Terminal half-life (t1/2) is the time in hours required for the concentration of the drug to reach half of its original value.

Terminal half-life (t1/2) is the time in hours required for the concentration of the drug to reach half of its original value.

CL/F is equal to dose/AUC0-infinity (dose divided by area under the plasma concentration versus time curve extrapolated to infinity \[AUC0-infinity\]).

CL/F is equal to dose/AUC0-infinity (dose divided by area under the plasma concentration versus time curve extrapolated to infinity \[AUC0-infinity\])

Ctau is the concentration of maribavir at the end of the dosing interval.

Vz/F is the volume of distribution associated with the terminal slope following extravascular administration divided by the fraction of dose absorbed.

Vz/F is the volume of distribution associated with the terminal slope following extravascular administration divided by the fraction of dose absorbed.

C0 is the lowest concentration reached by a drug before the next dose is administered.