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

NCT06079320 | Terminated Phase 2 Results DMC FDA Drug

• 2 other identifiers: C52410072023-505922-32-00
• Study Type: interventional
• Target: 16
• Locations: 4 countries
• Sites: 19

Brief Summary

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.

Conditions

Respiratory Syncytial Virus Infection

Outcome Measures

Primary Outcomes (1)

• Number of Participants With Respiratory Syncytial Virus (RSV) Related Hospitalization or Death From Any Cause Through Day 28

  RSV related hospitalization included a specialized acute medical care unit within an assisted living facility or nursing home.

  From Day 1 (start of study intervention) up to Day 28

Secondary Outcomes (17)

• Number of Participants With RSV-Related Visits (Urgent Care/ Emergency Department (ED)/Hospital) or Death From Any Cause Through Day 28

  From Day 1 (start of study intervention) up to Day 28

• Number of Participants With Progression of Lower Respiratory Tract Infection (LRTI) Through Day 10

  From randomization on Day 1 up to Day 10

• Number of Participants With Development of LRTI Through Day 10

  From randomization on Day 1 up to Day 10

• Number of Participants With Resolution of LRTI at Day 15

  Day 15

• Mean Number of Hospital Free Days Through Day 28

  From Day 1 (start of study intervention) up to Day 28

Study Arms (2)

Sisunatovir

EXPERIMENTAL

Drug: Sisunatovir

Placebo

PLACEBO COMPARATOR

Drug: Placebo

Interventions

Sisunatovir DRUG

Participants will receive tablets from Day 1 to Day 5

Sisunatovir

Placebo DRUG

Participants will receive matching placebo tablets from Day 1 to Day 5

Placebo

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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
• Any clinically significant ECG abnormality in the pre-dose ECG that, per investigator judgement, may affect participant safety
• Has hypersensitivity to or other contraindication to any of the components of the study interventions, as determined by the investigator.

Sponsors & Collaborators

• Pfizer: lead

Study Sites (19)

National Institute of Clinical Research

Garden Grove, California, 92844, United States

Location

National Institute of Clinical Research

Westminster, California, 92683, United States

Location

De La Cruz Research Center, LLC

Miami, Florida, 33184, United States

Location

Adult Medicine of Lake County, Inc.

Mt. Dora, Florida, 32757, United States

Location

Adult Medicine of Lake County

Mt. Dora, Florida, 32757, United States

Location

Accellacare - DuPage

Oak Lawn, Illinois, 60453, United States

Location

Mercury Street Medical Group, PLLC

Butte, Montana, 59701, United States

Location

DM Clinical Research - AOM

Brooklyn, New York, 11220, United States

Location

CHEAR Center LLC

The Bronx, New York, 10455, United States

Location

Preferred Primary Care Physicians, Preferred Clinical Research (Ofc 18)

Pittsburgh, Pennsylvania, 15236, United States

Location

Zenos Clinical Research

Dallas, Texas, 75230, United States

Location

Biopharma Informatic, LLC

Houston, Texas, 77043, United States

Location

Salma Mazhar, MD PA

Mesquite, Texas, 75149, United States

Location

SMS Clinical Research

Mesquite, Texas, 75149, United States

Location

Shanghai Minhang District Central Hospital

Shanghai, 201100, China

Location

Maharaja Agrasen Superspeciality Hospital

Jaipur, Rajasthan, 302039, India

Location

Koukankai Koukan Clinic

Kawasaki-Shi, Kanagawa, 210-0852, Japan

Location

National Hospital Organization Minami Kyoto Hospital

Jōyō, Kyoto, 610-0113, Japan

Location

Nanbu Tokushukai Hospital

Shimajiri, Okinawa, 901-0493, Japan

Location

Related Links

• To obtain contact information for a study center near you, click here.

MeSH Terms

Conditions

Respiratory Syncytial Virus Infections

Interventions

sisunatovir

Condition Hierarchy (Ancestors)

Pneumovirus Infections; Paramyxoviridae Infections; Mononegavirales Infections; RNA Virus Infections; Virus Diseases; Infections

Limitations and Caveats

A limitation of these results was the early study termination. Due to the small sample size, the study was no longer powered to establish the efficacy for the primary and key secondary efficacy endpoints for sisunatovir compared to placebo.

Results Point of Contact

• Title: Pfizer ClinicalTrials.gov Call Center
• Organization: Pfizer Inc.

ClinicalTrials.gov_Inquiries@pfizer.com

18007181021

Study Officials

• Pfizer CT.gov Call Center

  Pfizer

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Participants will be assigned to receive study intervention according to the assigned treatment group from the randomization scheme. Investigators will remain blinded to each participant's assigned study intervention until all participants complete treatment.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: This is a Phase 2/ Phase 3, superiority, adaptive, two parallel-arm, randomized, multi-center, placebo-controlled, double-blind study.

Study Record Dates

• First Submitted: October 6, 2023
• First Posted: October 12, 2023
• Study Start: December 8, 2023
• Primary Completion: September 30, 2024
• Study Completion: September 30, 2024
• Last Updated: November 10, 2025
• Results First Posted: November 10, 2025

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will share

Locations

CN (1); IN (1); US (14); JP (3)