Phase 2b Study of Oral S-337395 to Treat Symptomatic Adults With Respiratory Syncytial Virus at High Risk of Severe Disease

What this Trial Is About

This research aims to evaluate the antiviral effects of S-337395 compared with a placebo in adults who are not hospitalized but have respiratory syncytial virus RSV infection and are at high risk of progressing to severe disease. Participants must start treatment within 72 hours of showing RSV symptoms. The study is a Phase 2b trial and involves adults with specific risk factors such as older age and chronic lung or cardiovascular disease. Participants will be randomly assigned to receive either a high dose or low dose of S-337395, or a matching placebo. The treatment is given orally twice daily for up to 5 days. The study is double-blind, meaning neither participants nor researchers know which treatment is being administered during the trial. Throughout the study, participants will be monitored closely with assessments including nasal swabs to measure RSV RNA levels at several time points up to day 6. Researchers will also track symptoms using questionnaires and record any side effects up to 28 days. Blood samples will be collected to measure drug levels, and safety will be monitored throughout the study, which runs until December 2026.

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