TY - JOUR AU - Cerna, Petra AU - Coggins, Sally AU - Blyth, Michelle AU - Reagan, Krystle L. TI - From ebola to feline infectious peritonitis: the cross-species journey of GS-441524 and the future of antiviral translation JO - Rare Disease and Orphan Drugs Journal PY - 2026 VL - 5 IS - 2 SP - EP - 20 SN - ISSN 2771-2893 (Online) AB -

The feline coronavirus treatment GS-441524 represents a unique case of translational medicine in reverse: a compound developed for a rare human disease, abandoned in human clinical use, but successfully repurposed to treat a fatal veterinary condition affecting cats. Initially designed as a nucleoside analog for the Ebola virus, GS-441524 underwent preclinical safety testing in animals before being discovered to have unexpected clinical applications in feline infectious peritonitis (FIP), a historically untreatable disease in cats caused by a virulent systemic feline coronavirus (FCoV). This review traces the scientific and regulatory journey of GS-441524 from human antiviral candidate to life-saving feline treatment. We also expand the discussion to include the emerging use of other human antivirals, such as molnupiravir, in veterinary medicine. Ethical and public health tensions created by unregulated, community-driven drug access are examined, alongside the broader One Health implications, including antiviral resistance and the lack of surveillance in non-human hosts. Finally, we explore how lessons from FIP treatment may inform human medicine, particularly in the context of long COVID and future coronavirus pandemics. This translational scenario exemplifies both the potential and the pitfalls of cross-species drug translation, underscoring the need for integrated regulatory and ethical frameworks to support responsible innovation.

KW - Veterinary KW - feline medicine KW - remdesivir KW - infectious disease DO - 10.20517/rdodj.2026.07 UR - https://dx.doi.org/10.20517/rdodj.2026.07