New case series sharpens the picture on ocular FIP treatment

CURRENT BRIEF VERSION: A new case series adds early clinical detail on how ocular feline infectious peritonitis, or FIP, responds to antiviral treatment. In a 2025 Journal of Veterinary Internal Medicine report, 20 cats with ocular involvement were treated with remdesivir, GS-441524, or both over an 84-day course; 80% survived, and 82% of cats with uveitis that had long-term follow-up saw that inflammation resolve. Most cats began with remdesivir, often at higher doses used for ocular or neurologic disease, and many also received topical anti-inflammatory therapy. The report is especially relevant because ocular disease is more often linked to the non-effusive form of FIP and can sometimes be the main presenting sign, with findings ranging from iris color change and keratic precipitates to retinal lesions or detachment. The report arrives as U.S. veterinarians continue adapting to a new access landscape after FDA said in May 2024 it did not intend to enforce approval requirements for patient-specific compounded GS-441524 for FIP under certain conditions, while stressing these products remain unapproved drugs. (pubmed.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, the paper helps fill a practical gap: ocular lesions are common in FIP, but published data on how eye findings change during antiviral treatment have been limited. Updated international guidance notes FIP is an important differential for feline uveitis, and newer clinical discussion around FIP management emphasizes that cats may improve quickly early in treatment without necessarily being ready to stop therapy. That makes early recognition, ophthalmic documentation, dose selection, and follow-up especially important in practice, particularly since some ocular or neurologic damage may not fully reverse if treatment starts late. (abcdcatsvets.org)

What to watch: Expect closer attention to dosing protocols, relapse risk, long-term ocular outcomes, and more objective ways to judge when treatment can safely stop as more U.S. cases are managed with legally prescribed compounded GS-441524 and additional observational data emerge. (fda.gov)