A Study to Learn About the Study Medicine Sisunatovir in Adults With Respiratory Syncytial Virus (RSV) Infection

Study Overview
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Brief Summary
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The purpose of this study is to learn about the safety and effects of sisunatovir. Sisunatovir is studied for the possible treatment of Respiratory Syncytial Virus (RSV). RSV is a virus that causes lung infections with cold-like symptoms, but it can cause severe illness in some people. Sisunatovir is studied in adults: who are not admitted to the hospital and who have high chances of having a severe illness from RSV infection. This study is seeking participants who: Are confirmed to have RSV. Have symptoms of a lung infection. Are 18 years of age or older. Have one or more of the following which increases the chances of RSV illness: A long-term lung disease. heart failure. a condition that weakens the immune system. Are 65 years of age or older and do not have any of the conditions above Half of the participants in this study will receive sisunatovir. The other half will receive a placebo for 5 days. Placebo looks same like the study medicine but does not have any medication. Both sisunatovir and placebo will be taken by mouth. The study will compare the experiences of people receiving sisunatovir to those of the people who do not. This will help decide if sisunatovir is safe and effective. Participants will attend about 8-10 study visits over 5 weeks. During this time, they will have: visits at the study clinic, blood work, swabs of the nose, questionnaires, a follow-up phone call.

Official Title
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AN INTERVENTIONAL PHASE 2/3, ADAPTIVE, MULTI-CENTER, RANDOMIZED, DOUBLE-BLIND STUDY TO INVESTIGATE EFFICACY AND SAFETY OF ORAL SISUNATOVIR COMPARED WITH PLACEBO IN NON-HOSPITALIZED SYMPTOMATIC ADULTS WITH RESPIRATORY SYNCYTIAL VIRUS INFECTION WHO ARE AT RISK OF PROGRESSION TO SEVERE ILLNESS

Conditions
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Respiratory Syncytial Virus Infection

Intervention / Treatment
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* Drug: Sisunatovir
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participants aged 18 years or older at screening. Diagnosis of RSV infection collected within 5 days prior to randomization. New onset or worsening (if present chronically) of at least one of the following signs and/or symptoms consistent with a viral acute respiratory infection (ARI), within 5 days prior to randomization: nasal congestion, nasal discharge, sore throat, cough, sputum production, shortness of breath, or wheezing. Has at least 1 of the following characteristics or underlying medical conditions: a) 65 years of age or older b) Chronic lung disease, c) Heart failure, d) Immunosuppressive disease/condition or immune-weakening medications Exclusion Criteria: Any medical or psychiatric condition that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study or interfere with the evaluation of response to the study intervention. Diagnosis of viral respiratory infections other than RSV including influenza and SARS-CoV-2 Current need for hospitalization or anticipated need for hospitalization for any reason to provide inpatient/acute care within 24 hours after randomization Known history or has risk factors for QT prolongation or Torsades de Pointes or congenital deafness, family history of long QT syndrome or unexplained sudden death, or a standard 12-lead ECG with QTcF ≥450 ms Has hypersensitivity to or other contraindication to any of the components of the study interventions, as determined by the investigator.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: This is a Phase 2/ Phase 3, superiority, adaptive, two parallel-arm, randomized, multi-center, placebo-controlled, double-blind study.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sisunatovir<br> | Drug: Sisunatovir<br>* Participants will receive tablets from Day 1 to Day 5<br>|
| Placebo Comparator: Placebo<br> | Drug: Placebo<br>* Participants will receive matching placebo tablets from Day 1 to Day 5<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of participants with Respiratory Syncytial Virus (RSV)-related hospitalization or death from any cause through Day 28, among patients treated ≤3 days after RSV symptom onset |  | 28 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of participants with RSV-related hospitalization or death from any cause through Day 28. |  | 10 days and 28 days | 
| Proportion of participants with Respiratory Syncytial Virus (RSV)-related visits or death from any cause through Day 28. |  | 28 days | 
| Proportion of participants with progression or development of Lower Respiratory Tract Infection (LRTI) through Day 10 |  | 10 days | 
| Proportion of participants with resolution of LRTI at Day 15. |  | 15 days | 
| Mean number of days alive and free from hospital stay (hospital-free days) through Day 28. |  | 28 days |