hVIVO plc (AIM: HVO), a specialist contract research organisation (CRO) in infectious disease testing, has announced positive topline results from a Phase 2a Respiratory Syncytial Virus (RSV) human challenge trial for Enanta Pharmaceuticals' antiviral candidate EDP-323. This trial involved 142 healthy adult volunteers and demonstrated significant antiviral efficacy.

Participants were divided into three groups - high dose, low dose and placebo. Results indicated that EDP-323 achieved an 85-87% reduction in viral load as measured by qRT-PCR, a 97-98% reduction in infectious viral load via viral culture, and a 66-78% decrease in total clinical symptoms score, all with p-values less than 0.0001.

The successful outcomes underscore the value of human challenge trials in expediting efficacy data and mitigating risks in later-stage clinical development. With over 30 years of experience, hVIVO supports crucial research across various respiratory viruses, including RSV and COVID-19.

EDP-323, an oral antiviral, has received U.S. Food and Drug Administration (FDA) Fast Track designation.

Enanta's first RSV candidate, Zelicapavir (EDP-938), has also shown promising results in prior trials.

hVIVO operates from its state-of-the-art facilities in Canary Wharf, London, the world's largest commercial human challenge trial unit, equipped with advanced virology and immunology laboratories. The Group offers a comprehensive suite of early clinical development services, maintaining partnerships with four of the top ten global biopharma companies.