Study of Obeldesivir to Treat Children With Respiratory Syncytial Virus (RSV) Infection

Key Inclusion Criteria:

• Participants assigned male or female at birth, from birth to < 5 years of age whomeet one of the following criteria, where permitted according to local law andapproved nationally and by relevant institutional review board or independent ethicscommittee:

• Cohort 1: Infants and children from 4 weeks postnatal age, weighing ≥ 1.5 kg to < 40 kg

• Cohort 2: Neonates, either born at term or preterm, weighing ≥ 1.5 kg to < 6 kg

• RSV infection diagnosis ≤ 3 days prior to randomization.

• Negative test for influenza A/B, and SARS-CoV-2 infection ≤ 7 days prior torandomization.

• Onset of RSV signs or symptoms ≤ 3 days prior to randomization.

• Presence of at least 1 sign or symptom of RSV infection at screening and atrandomization.

Key Exclusion Criteria:

• Currently requiring or expected to require hospitalization for RSV infection within 48 hours after randomization.

• Documented previous infection and/or hospitalization for RSV during the currentrespiratory virus season.

• Diagnosed with acute concurrent active systemic infections requiring treatment withsystemic antiviral, antibacterial, antifungal, or antimycobacterial therapy, or withany documented respiratory viral infection (other than RSV), ≤ 7 days prior torandomization.

• History of asthma or recurrent wheezing.

• Neuromuscular disease that affects swallowing.

• Cystic fibrosis.

• Participants who are immunocompromised.

• Alanine aminotransferase ≥ 5 × upper limit of normal (ULN).

• Abnormal renal function.

• Concurrent or previous treatment with other agents with actual or possible directantiviral activity against RSV, received within 28 days or within 5 half-lives,whichever is longer, prior to randomization.

• Received palivizumab within 100 days, or nirsevimab within 1 year, or other RSVspecific monoclonal antibody within 5 half-lives of the antibody, prior torandomization.

• Participant whose mother received RSV vaccination during pregnancy and who is < 1year old prior to randomization.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.