A Study to Learn About the Amount of the Study Medicine (Sisunatovir) in Blood and Its Safety in Infants and Children With Pneumonia Caused by RSV

AN INTERVENTIONAL, PHASE 1b, RANDOMIZED, DOUBLE-BLIND, SPONSOR-OPEN, PLACEBO-CONTROLLED, MULTI-CENTER, DOSE-FINDING STUDY TO EVALUATE SAFETY, TOLERABILITY AND PHARMACOKINETICS OF SISUNATOVIR IN PEDIATRIC PARTICIPANTS UP TO AGE 60 MONTHS WITH RESPIRATORY SYNCYTIAL VIRUS (RSV) LOWER RESPIRATORY TRACT INFECTION (LRTI)

Status

Active, not recruiting

Phases

Phase 1

Study type

Interventional

Source

JPRN

Registry ID

JPRN-jRCT2031230445

Enrollment

108

Registered

2023-11-11

Start date

2024-04-02

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Respiratory Syncytial Virus Infections

Interventions

Sisunatovir Oral or Nasogastric tube Placebo Oral or Nasogastric tube

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1 day to =2.5 kg to <=23 kg Positive RSV diagnostic test, antigen or molecular test Evidence of Lower Respiratory Tract Infection (LRTI)

Exclusion criteria

Exclusion criteria: Premature infants (gestational age less than 35 weeks) AND <1 year of post-natal age Neonates with intrauterine growth restriction Expected to receive an antiviral for another viral infection within 10 days of screening Suspected or confirmed clinically significant moderate or severe bacterial infection that may interfere with the evaluation of response to the study intervention Known to have significant comorbidities that would limit the ability to administer the study intervention or evaluate the safety or clinical response to the study intervention

Design outcomes

Primary

Measure	Time frame
Incidence of Treatment Emergent Adverse Events (TEAEs) Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs) leading to discontinuations Incidence of clinically significant abnormal laboratory values Incidence of clinically significant abnormal Electrocardiogram (ECG) parameters Incidence of clinically significant abnormal vital signs	—

Secondary

Measure	Time frame
Plasma concentrations of sisunatovir at steady state (Day 3 or later).	—

Countries

Japan, South Africa, United States

Contacts

Public ContactClinical Trials Information Desk

Pfizer R&D Japan G.K.

clinical-trials@pfizer.com+81-3-5309-7000

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: Jul 3, 2026