Number of Participants Who Achieved Confirmed CMV Viremia Clearance and CMV Infection Symptom Control at the End of Week 8, Followed by Maintenance of Treatment Effect at Week 16 [Time Frame: Week 8 up to Week 16]
Number of Participants Who Achieved Confirmed Clearance of Plasma CMV DNA (CMV Viremia Clearance) at Week 8 After Receiving 8 Weeks of Study Assigned Treatment [Time Frame: Week 8]
Number of Participants Who Achieved Confirmed CMV Viremia Clearance After Receiving 8 Weeks of Study-assigned Treatment Through Weeks 12, 16 and 20 [Time Frame: Week 8 through Weeks 12, 16 and 20]
Number of Participants Who Maintained Confirmed CMV Viremia Clearance at Week 8 After Receiving Study-Assigned Treatment Through Study Weeks 12 and 20 Regardless of Whether Study Assigned Treatment Was Completed [Time Frame: Week 8 through Weeks 12 and 20]
Number of Participants With Confirmed Recurrence of Viremia During First 8 Weeks of the Study [Time Frame: Up to Week 8]
Number of Participants With Confirmed Recurrence of Viremia During the Follow-up Period [Time Frame: From Week 9 up to Week 20]
Number of Participants With Confirmed Recurrence of Viremia at Any Time During the Study [Time Frame: Up to Week 20]
Number of Participants With Confirmed Recurrence of Viremia While on Study Treatment and Off Treatment [Time Frame: Baseline up to Week 20]
Number of Participants With Grade 3 or 4 (Shift From Baseline Grade <3) and Grade 4 Neutropenia (Shift From Baseline Grade <4) While on Study Treatment [Time Frame: From start of study drug to end of study drug + 1 day (up to approximately Week 8)]
Number of Participants With Treatment-Emergent Adverse Events During the On-Treatment Period [Time Frame: From the start of the study treatment to 7 days after the last dose of study treatment (up to approximately Week 9)]
Predose Concentration (Cmin) of Maribavir [Time Frame: Weeks 1, 4, and 8: pre-morning dose]
Area Under the Concentration-Time Curve Over the 12-Hour Dosing Interval at Steady State AUC(0-tau) of Maribavir for Adolescent Participants Only [Time Frame: Pre-morning dose, 1, 2, 3, 4, 6, 8, and 12 hours post-morning dose of Week 1]
Maximum Observed Plasma Concentration (Cmax) of Maribavir for Adolescent Participants Only [Time Frame: Pre-morning dose, 1, 2, 3, 4, 6, 8, and 12 hours post-morning dose of Week 1]
Time When Maximum Concentration is Observed (Tmax) of Maribavir for Adolescent Participants Only [Time Frame: Pre-morning dose, 1, 2, 3, 4, 6, 8, and 12 hours post-morning dose of Week 1]
Apparent Oral Clearance (CL/F) of Maribavir for Adolescent Participants Only [Time Frame: Pre-morning dose, 1, 2, 3, 4, 6, 8, and 12 hours post-morning dose of Week 1]
Apparent Volume of Distribution (Vz/F) of Maribavir for Adolescent Participants Only [Time Frame: Pre-morning dose, 1, 2, 3, 4, 6, 8, and 12 hours post-morning dose of Week 1]
