Enanta Pharmaceuticals is set to present new clinical data for two of its investigational respiratory syncytial virus (RSV) antivirals at major European infectious disease conferences in the coming months.
The Watertown, Massachusetts-based biotechnology company announced that findings from its Phase 2 study of zelicapavir in children with RSV will be featured at the 43rd Annual Meeting of the European Society for Paediatric Infectious Diseases (ESPID) in May 2025. Additionally, data from a Phase 2a human challenge study of EDP-323 in adults will be presented at the European Society of Clinical Microbiology & Infectious Diseases Global 2025 (ESCMID) conference in April.
Zelicapavir Data in Pediatric RSV Patients
The zelicapavir data will be available as an E-Poster at ESPID 2025, held May 26-30 in Bucharest, Romania. The presentation, titled "Antiviral Treatment of RSV in Children: Virology and PK Results of a Randomized Double-Blind Placebo-Controlled International Trial of Zelicapavir (EDP-938)," will be presented by Dr. John DeVincenzo.
This presentation will highlight results from the Phase 2 pediatric study initially announced in December 2024, with new data focusing on population pharmacokinetics/pharmacodynamics (PK/PD) and time to viral load negativity. Zelicapavir is an oral, non-nucleoside small-molecule that targets the RSV N-protein to inhibit viral replication.
EDP-323 Human Challenge Study Results
Separately, Enanta will present data from its Phase 2a human challenge study of EDP-323 at ESCMID Global 2025 in Vienna, Austria, on April 13. This oral ePoster presentation, "EDP-323, a First-in-Class, Oral, RSV L-Protein Inhibitor Reduces Disease Severity (Respiratory Mucus Production) and Accelerates Viral Clearance in a Human Viral Challenge Study," will also be delivered by Dr. John DeVincenzo.
The presentation will include previously announced results from September 2024, along with new data specifically highlighting EDP-323's effects on respiratory mucus production. EDP-323 represents a different mechanism of action from zelicapavir, functioning as a first-in-class inhibitor of the RSV polymerase (L-protein).
Dual Approach to RSV Treatment
Enanta's dual-pronged approach to RSV treatment development is noteworthy, as the company advances two oral antivirals with distinct mechanisms of action. RSV remains a significant global health concern, particularly for vulnerable populations such as young children and older adults.
"These presentations represent important milestones in our RSV program," said a company representative. "By targeting different viral proteins with zelicapavir and EDP-323, we're exploring multiple pathways to potentially address the significant unmet need for effective RSV treatments."
About Enanta's RSV Program
Enanta Pharmaceuticals has established itself as a leader in small molecule drug discovery, with a particular focus on viral infections. The company's RSV program is a central component of its clinical pipeline, alongside its emerging immunology portfolio targeting inflammatory diseases.
The company utilizes a chemistry-driven approach to drug discovery and has previously demonstrated success with glecaprevir, a protease inhibitor that forms part of AbbVie's leading treatment regimen for hepatitis C virus (HCV) infection, marketed as MAVYRET® in the U.S. and MAVIRET® internationally.
Royalties from this HCV collaboration continue to support Enanta's operations and ongoing research efforts in RSV and other therapeutic areas.
RSV Treatment Landscape
RSV is a common respiratory virus that usually causes mild, cold-like symptoms but can lead to serious illness, especially in infants, young children, and older adults. Despite its prevalence and impact, there are limited treatment options available, particularly for pediatric patients.
The development of effective oral antivirals for RSV represents a significant unmet medical need. Current management of RSV infections primarily involves supportive care, with few specific antiviral treatments approved, especially for children.
If successful in later-stage trials, Enanta's RSV antivirals could potentially provide much-needed therapeutic options for patients across age groups, potentially reducing disease severity, shortening illness duration, and improving clinical outcomes.
