New evidence sharpens the outlook for ocular FIP treatment
CURRENT BRIEF VERSION: Cats with ocular feline infectious peritonitis may have a clearer treatment path as evidence around antivirals continues to build. A 2025 observational case series in the Journal of Veterinary Internal Medicine found that remdesivir, GS-441524, or a combination of the two improved FIP-associated uveitis in 82% of cats with ocular involvement. In that study, 20 cats with ocular FIP were treated with injectable remdesivir, oral GS-441524, or both, adding clinical detail to a part of FIP care that has been less well described than treatment of effusive disease. Vet-focused clinical education has highlighted that ocular disease can be the main presenting feature in some cats and may include anterior chamber changes such as keratic precipitates, iris color change, dyscoria, hyphema, hypopyon, or fibrin, as well as posterior lesions including chorioretinal changes, retinal hemorrhage, detachment, or perivascular cuffing. The update lands as U.S. veterinarians have had broader practical access to compounded oral GS-441524 since June 1, 2024, after FDA said it did not intend to enforce approval requirements for patient-specific compounded GS-441524 prescribed for cats with FIP under Guidance for Industry #256. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinary teams, ocular FIP is one of the presentations that often pushes dosing, duration, monitoring, and prognosis conversations into more complex territory. Recent guidance and reviews suggest cats with ocular or neurologic signs may need higher antiviral doses and, in some cases, longer treatment courses than cats without eye or CNS involvement because those tissues can be harder to penetrate. Practical discussions in continuing education have also emphasized that cats often improve clinically within the first week, but early improvement does not necessarily mean the virus has been cleared, making relapse monitoring and treatment-stop decisions especially important. That matters in day-to-day practice because earlier recognition of anterior or posterior uveitis, faster confirmation of suspected FIP, and realistic counseling for pet parents may improve adherence and outcomes while helping clinics move cases away from unregulated sourcing. (abcdcatsvets.org)
What to watch: Expect more emphasis on dose refinement, relapse monitoring, and standardized protocols for ocular and neurologic FIP as larger datasets and consensus guidance continue to emerge. Another area to watch is use of more objective treatment-stop criteria, including trends in acute phase proteins such as serum amyloid A and alpha-1 acid glycoprotein alongside the albumin:globulin ratio, rather than relying only on how quickly a cat appears to feel better. (abcdcatsvets.org)