ASN500

ASN500 is a high-potency monoclonal antibody designed for the prevention of respiratory syncytial virus (RSV) infections. Developed by Arsanis in collaboration with the Bill & Melinda Gates Foundation, the antibody was engineered to neutralize RSV by targeting the viral fusion (F) protein. Pre-clinical data suggested that ASN500 could offer significant advantages over existing preventive therapies, such as palivizumab, due to its high potency and extended half-life, which potentially allowed for lower dosing and more convenient routes of administration. Although the company initially planned to advance the candidate into Phase 1 clinical trials in 2019, development was deprioritized following the merger of Arsanis with X4 Pharmaceuticals in early 2019.