NCT07214571

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

A Phase 2b, Multicenter, Randomized, Double-blind, Placebo-controlled, Parallel-group Study to Evaluate the Safety, Tolerability, and Efficacy of S-337395 in Symptomatic Nonhospitalized Adults With Respiratory Syncytial Virus Who Are at High Risk of Progression to Severe Disease

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 192 (estimated)
• Sponsor: Shionogi · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

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

Interventions

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

Timeline

• Start date: 2025-12-11
• Primary completion: 2026-12-30
• Completion: 2026-12-30
• First posted: 2025-10-09
• Last updated: 2026-03-31

Locations

64 sites across 4 countries: United States, Bulgaria, Japan, South Africa

Regulatory

• FDA-regulated drug study