A Study of S-337395 in Symptomatic Nonhospitalized Adults With Respiratory Syncytial Virus (RSV) Who Are at High Risk of Progression to Severe Disease

NCT07214571 | Recruiting Phase 2 FDA Drug

• 1 other identifier: 2402T1432
• Study Type: interventional
• Target: 192
• Locations: 5 countries
• Sites: 68

Brief Summary

The main purpose of this study is to investigate the antiviral effect of S-337395 compared with placebo among nonhospitalized adult participants with high-risk factors for progression to severe RSV infection starting intervention within 72 hours of RSV symptom onset.

Conditions

Respiratory Syncytial Virus Infections

Keywords

Respiratory Syncytial Virus Infections; RSV infection; Viral infection; S-337395; Acute lower respiratory tract infection

Outcome Measures

Primary Outcomes (3)

• Change From Baseline in RSV Ribonucleic Acid (RNA) Load by Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) (Nasopharyngeal Swab) at Day 2

  Baseline, Day 2

• Change From Baseline in RSV RNA Load by qRT-PCR (Nasopharyngeal Swab) at Day 4

  Baseline, Day 4

• Change From Baseline in RSV RNA Load by qRT-PCR (Nasopharyngeal Swab) at Day 6

  Baseline, Day 6

Secondary Outcomes (30)

• Number of Participants With Treatment-emergent Adverse Events (TEAEs)

  Day 1 up to Day 28

• Change From Baseline in Severity of RSV Respiratory Symptom Score Based on the Respiratory Infection Intensity and Impact Questionnaire (RiiQ) Respiratory Symptom Subscale (RiiQ-RSS)

  Baseline up to Day 6

• Change From Baseline in Severity of RSV Systemic Symptoms Score Based on the RiiQ Systemic Symptom Subscale (RiiQ-SSS)

  Baseline up to Day 6

• Change From Baseline in Severity of RSV Total Symptoms Score Based on the Combined RiiQ RSS and RiiQ-SSS

  Baseline up to Day 6

• Time to First Resolution of All Respiratory RSV-related Symptoms Based on the RiiQ-RSS

  Baseline up to Day 6

Study Arms (3)

S-337395 High Dose

EXPERIMENTAL

Participants will receive a high dose of S-337395 twice daily (BID) orally for up to 5 days.

Drug: S-337395

S-337395 Low Dose

EXPERIMENTAL

Participants will receive a low dose of S-337395 BID orally for up to 5 days.

Drug: S-337395

Placebo

PLACEBO COMPARATOR

Participants will receive matching placebo BID orally for 5 days.

Drug: Placebo

Interventions

S-337395 DRUG

S-337395 will be administered per schedule specified in the arm description.

S-337395 High Dose; S-337395 Low Dose

Placebo DRUG

Placebo matched to S-337395 will be administered per schedule specified in the arm description.

Placebo

Eligibility Criteria

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

You may qualify if:

• Participants who have new onset or worsening (if present chronically) of at least 1 of the following signs and/or symptoms consistent with a viral acute respiratory infection within 72 hours prior to randomization: fever, nasal congestion, nasal discharge, sore throat, cough, sputum production, shortness of breath, or wheezing.
• Participants diagnosed with RSV infection preferably using a rapid polymerase chain reaction (PCR) or other molecular-based diagnostic assay.
• Has at least 1 of the following risk factors for severe RSV disease:
• ≥ 75 years of age;
• Chronic lung disease that is symptomatic and requiring chronic treatment; and
• Chronic cardiovascular disease that is symptomatic and requiring chronic treatment.
• With the exception of the RSV disease, medically stable on the basis of medical history, physical examination, vital signs, and 12-lead electrocardiogram (ECG) performed at screening.

You may not qualify if:

• Hospitalized or expected to be hospitalized within 24 hours of screening.
• Is considered by the investigator to be immunocompromised, due to an underlying medical condition or medical therapy, chemotherapy, radiation, stem cell or solid organ transplant.
• Has known allergies, hypersensitivity, or intolerance to S-337395 or to any of the excipients of the S-337395 or placebo formulation.
• Suspicion or known severe renal impairment.
• Any other medical or psychiatric condition making the participant unsuitable for the current study or interfering with the evaluation of response to the study intervention in the opinion of the investigator/subinvestigator.
• Has received a therapy intended to treat RSV infection within 14 days prior to screening.
• Is receiving chemotherapy or immunotherapy for malignancy.
• Has received RSV vaccination within 7 days prior to screening.
• Has had either confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or influenza infection (test was positive) during the 28 days prior to screening.
• Has any other confirmed clinically relevant respiratory infection by any pathogen at, or within 28 days of screening.

Sponsors & Collaborators

• Shionogi: lead

Study Sites (68)

LA Universal Research Center, Inc.

Los Angeles, California, 900057-4040, United States

RECRUITING

Med Partnes, Inc - Elligo- PPDS

Toluca Lake, California, 91602-3457, United States

RECRUITING

Hope Clinical Trials - 3970 W Flagler St.

Coral Gables, Florida, 33134-1642, United States

RECRUITING

Beautiful Minds Clinical Research Center

Cutler Bay, Florida, 33157, United States

RECRUITING

Doral Medical Research

Hialeah, Florida, 33016-1897, United States

RECRUITING

Southern Clinical Research

Miami, Florida, 33125-4106, United States

RECRUITING

LCC Medical Research - Miami - BTC - PPDS

Miami, Florida, 33126, United States

RECRUITING

Nuren Medical and Research Center

Miami, Florida, 33144-2069, United States

RECRUITING

Continental Clinical Research, LLC

Miami, Florida, 33144-4273, United States

RECRUITING

Dynamic Medical Research, LLC - Miami

Miami, Florida, 33144, United States

RECRUITING

Miami Clinical Research, LLP.

Miami, Florida, 33155, United States

RECRUITING

Reed Medical Research

Miami, Florida, 33176-8709, United States

RECRUITING

Palm Springs Community Health Center

Miami Lakes, Florida, 33014-2266, United States

RECRUITING

Oceanic Research Group, LLC

North Miami Beach, Florida, 33169-5513, United States

RECRUITING

CDC Research Institute, LLC

Port Saint Lucie, Florida, 34952-7539, United States

RECRUITING

Cordova Research Insittute

Sweetwater, Florida, 33182, United States

RECRUITING

Better Life Clinical Research LLC

Tampa, Florida, 33607, United States

RECRUITING

Research Bay,Inc.

Tampa, Florida, 33607, United States

RECRUITING

Santos Research Center - 5927 Webb Rd

Tampa, Florida, 33615-3219, United States

RECRUITING

Angels Clinical Research Institute Tampa-Palm Springs

Tampa, Florida, 336214-2869, United States

RECRUITING

Covenant Pulmonary Criticial Care and Research Ins

East Point, Georgia, 30344-3604, United States

RECRUITING

Clay Platte Family Medicine - CCT Research

Kansas City, Missouri, 64151-2411, United States

RECRUITING

Prime Global Research, Inc.

The Bronx, New York, 10456-2102, United States

RECRUITING

Progressive Medicine of the Triad, LLC

Winston-Salem, North Carolina, 27103, United States

RECRUITING

University Hospitals Cleveland Medical Center

Cleveland, Ohio, 44106, United States

RECRUITING

Epic Medical Research - Chickasha

Chickasha, Oklahoma, 73018-2738, United States

RECRUITING

Rhode Island Hospital

Providence, Rhode Island, 02903-4923, United States

RECRUITING

Epic Med. Research LLC, DeSoto

DeSoto, Texas, 75115-2043, United States

RECRUITING

SMS Clinical Research, LLC - 400 W. Kearney St

Mesquite, Texas, 751497, United States

RECRUITING

Clinical Research Partners LLC

Richmond, Virginia, 23226-3786, United States

RECRUITING

Frontier Clinical Research Waterfront

Morgantown, West Virginia, 26501, United States

RECRUITING

Medical Center Hera EOOD, Montana

Montana, Sofia, 3400, Bulgaria

RECRUITING

Multiprofile Hospital For Active Treatment Dr Tota Venkova - PRATIA - PPDS

Gabrovo, 5300, Bulgaria

RECRUITING

MCpulmo-2018 Ltd

Haskovo, 6300, Bulgaria

RECRUITING

Medical Center Hera EOOD

Sofia, 1510, Bulgaria

RECRUITING

Kamezawa Clinic

Kasugai-Shi, Aiti, 0568-56-5050, Japan

RECRUITING

Hosokawa Surgical Clinic

Nagoya-Shi Nakamura-Ku, Aiti, 052-481-9921, Japan

RECRUITING

Doi Clinic

Chikushino-shi, Fukuoka, 092-926-7415, Japan

RECRUITING

Irie Clinic

Fukuoka, Fukuoka, 092-651-4521, Japan

RECRUITING

Tomita Internal Medicine Clinic

Fukuoka-Shi Chuo-Ku, Fukuoka, 092-707-2103, Japan

RECRUITING

PS Clinic

Fukuoka-Shi Hakata-Ku, Fukuoka, 092-283-7777, Japan

RECRUITING

Medical corporation Aimeikai Morizono internal medicine

Kitakyushu-Shi Yahatanishi-Ku, Fukuoka, 093-611-5335, Japan

RECRUITING

Social Medical Corporation the Chiyukai foundation Shin Komonji Hospital

Kitakyushu-Shi, Fukuoka, 093-391-1001, Japan

RECRUITING

Shizuka Clinic

Takasaki-shi, Gunma, 027-370-0777, Japan

RECRUITING

Social medical corporation Keiwakai Nishioka Hospital

Sapporo-Shi Toyohira-Ku, Hokkaidô, 011-853-8322, Japan

RECRUITING

Terada Internal Medicine and Respiratory Department

Himeji-shi, Hyôgo, 079-285-0111, Japan

RECRUITING

Tsuchiura Beryl Clinic

Tsuchiura-Shi, Ibaraki, 029-835-3002, Japan

RECRUITING

Gajyumaru Clinic Tsukuba

Tsukuba, Ibaraki, 029-893-4159, Japan

RECRUITING

Shiwa Central Pediatrics

Shiwa-gun, Iwate, 019-672-1110, Japan

RECRUITING

Medical corporation Kojinkai Takahashi Internal Medicine

Kawasaki-Shi, Kanagawa, 044-740-2717, Japan

RECRUITING

Ebino Centro Clinic

Ebino, Miyazaki, 0984-33-5777, Japan

RECRUITING

Rinku General Medical Center

Izumisano, Osaka, 072-469-3111, Japan

RECRUITING

Yamaichi Building Internal Medicine Clinic

Adachi-Ku, Tokyo, 03-884-8888, Japan

RECRUITING

Medical Corporation Hosoda Clinic

Katsushika-ku, Tokyo, 03-3657-3430, Japan

RECRUITING

Medical Corporation Shirayurikai Swing Building Nozaki Clinic

Musashino, Tokyo, 0422-36-3534, Japan

RECRUITING

Nogata Clinic

Nakano-ku, Tokyo, 03-3389-2201, Japan

RECRUITING

Noguchi Internal Medicine Clinic

Nakano-Ku, Tokyo, 03-3926-0007, Japan

RECRUITING

Sato Clinic

Shibuya-Ku, Tokyo, 03-5447-2477, Japan

RECRUITING

Mih Clinic Yoyogi

Shibuya-Ku, Tokyo, 03-6276-5385, Japan

RECRUITING

Medical corporation Hiroyukai Yotsuya Internal Medicine

Shinjuku-Ku, Tokyo, 03-5368-0675, Japan

RECRUITING

Yoshida Clinic

Suginami-ku, Tokyo, 03-5347-7300, Japan

RECRUITING

Sekino Hospital

Toshima-Ku, Tokyo, 03-3986-5501, Japan

RECRUITING

Kijima Kids Clinic

Higashiokitama-gun, Yamagata, 0238-54-0135, Japan

RECRUITING

Toda Internal Medicine and Neurology

Hyōgo, 078-947-5575, Japan

RECRUITING

Alergo-Med Osrodek Badan Klinicznych sp z o.o

Tarnów, Lesser Poland Voivodeship, 33-100, Poland

RECRUITING

Ostrowieckie Centrum Medyczne Spólka Cywilna Anna Olech-Cudzik, Krzysztof Cudzik

Ostrowiec Świętokrzyski, Świętokrzyskie Voivodeship, 27-400, Poland

RECRUITING

Newtown Clinical Research Centre

Johannesburg, Gauteng, 2001, South Africa

RECRUITING

Be Part Yoluntu Centre

Paarl, Western Cape, 7655, South Africa

RECRUITING

MeSH Terms

Conditions

Respiratory Syncytial Virus Infections; Virus Diseases

Condition Hierarchy (Ancestors)

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

Central Study Contacts

Shionogi Clinical Trials Administrator Clinical Support Help Line

CONTACT

800-849-9707; Shionogiclintrials-admin@shionogi.co.jp

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 8, 2025
• First Posted: October 9, 2025
• Study Start: December 11, 2025
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): December 30, 2026
• Last Updated: May 6, 2026

Record last verified: 2026-05

Locations

JP (29); PL (2); BU (4); ZA (2); US (31)