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

Study Overview
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Brief Summary
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The purpose of the study is to learn about the safety and amount of sisunatovir in the blood of infants and children up to age 60 months. These children have Lower Respiratory Tract Infection (LRTI) caused by Respiratory Syncytial Virus (RSV). LRTI is the infection to the lower airways such as lungs. This study will help inform the amount of sisunatovir to be used in future studies of sisunatovir in children. This study is seeking for participants who: Are 1 day to less than or equal to 60 months of age weigh more than or equal to 2.5 kilograms to less than or equal to 23 kilograms. Have been tested to have RSV by medical tests. show signs of LRTI. All participants in the study will receive many amounts of sisunatovir or placebo. Placebo is a pill that does not have any medicine in it. Up to 7 visits are required for the study. Some of these visits include checking participants health over the phone and/or a visit at home. The study will compare the experiences of infants and children receiving sisunatovir to identify the amount of sisunatovir to be used in future studies in infants and children.

Official Title
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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)

Conditions
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Respiratory Syncytial Virus Infections

Intervention / Treatment
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* Drug: Placebo
* Drug: Active


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 1 day to ≤60 months of age and weight ≥2.5 kg to ≤23 kg Positive RSV diagnostic test, antigen or molecular test Evidence of Lower Respiratory Tract Infection (LRTI) 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

Ages Eligible for Study
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Minimum Age: 1 Day
Maximum Age: 60 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Oral or Nasogastric tube (NG) | Drug: Placebo<br>* Placebo<br>|
| Active Comparator: Sisunatovir<br>Oral or NG tube | Drug: Active<br>* Sisunatovir<br>* Other names: PF-07923568, RV521;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of Treatment Emergent Adverse Events (TEAEs) |  | Day 1 to Day 33 | 
| Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs) leading to discontinuations |  | Day 1 to Day 33 | 
| Incidence of clinically significant abnormal laboratory values |  | Day 1 to Day 33 | 
| Incidence of clinically significant abnormal Electrocardiogram (ECG) parameters |  | Day 1 to Day 33 | 
| Incidence of clinically significant abnormal vital signs. |  | Day 1 to Day 33 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma concentrations of sisunatovir at steady state (Day 3 or later). |  | Day 3 to Day 5 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Lower Respiratory Tract Infection