Ocular FIP treatment enters a more practical era for vets

CURRENT BRIEF VERSION: Ocular feline infectious peritonitis, once a near-certain fatal diagnosis, is increasingly being discussed as a treatable presentation as veterinarians gain more experience with antiviral therapy, especially GS-441524 and remdesivir. Recent guidance and reviews now frame ocular involvement as a key factor in treatment planning, with higher or adjusted dosing often recommended when eye or neurologic signs are present. Clinically, ocular disease is seen far more often in non-effusive FIP than effusive disease, and signs can range from anterior uveitis, hyphema, corneal edema, anisocoria, and iris color change to posterior segment lesions, retinal hemorrhage, detachment, and vision loss. In the U.S., access also changed in 2024, when the FDA said it does not intend to enforce approval requirements for patient-specific compounded GS-441524 prescriptions for cats with FIP under outlined conditions, even though compounded products remain unapproved drugs. (pubmed.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, the shift is practical as much as clinical. Ocular signs can be part of non-effusive FIP or even the dominant presenting feature, and newer guidance highlights that those cats may need different dosing considerations than uncomplicated cases because the eyes and CNS are harder-to-penetrate sites. That makes early recognition, ophthalmic assessment, client counseling, and careful follow-up more important, especially because cats may improve clinically within days even when treatment decisions about duration still require caution. Published evidence still relies heavily on case series, retrospective data, and studies using products with variable drug content, and diagnosis in practice often remains presumptive rather than definitive. (academic.oup.com)

What to watch: Expect more discussion around standardized dosing for ocular and neurologic FIP, treatment duration, and whether higher-dose induction protocols or biomarker-guided stopping criteria such as serum amyloid A, alpha-1 acid glycoprotein, and albumin:globulin ratio can safely shorten therapy in selected cats. Another key question is how compounded U.S. products compare with formulations used in published studies. (pubmed.ncbi.nlm.nih.gov)