FDA Announces Position on Use of Compounded GS-441524 to Treat FIP
May 10, 2024
Because no FDA approved drug is available to treat Feline Infectious Peritonitis in cats, the U.S. Food and Drug Administration does not intend to enforce new animal drug approval requirements for products compounded from GS-441524, when prescribed by a veterinarian for a specific cat patient for the treatment of Feline Infectious Peritonitis under the conditions listed in Guidance for Industry (GFI) #256 Compounding Animal Drugs from Bulk Drug Substances.
The FDA is aware of social media posts suggesting that compounded GS-441524 will be “legally” available in the United States starting June 1. The agency reminds compounding pharmacies, veterinarians and pet owners that animal drugs compounded from bulk drug substances are unapproved drugs and are not, in fact, legal. However, in GFI #256, the FDA has described certain conditions where the agency does not intend to take enforcement actions for compounded products for use in animals.
GFI #256 also specifies that, if veterinarians wish to obtain animal drugs compounded from a bulk drug substance without a patient-specific prescription (office stock), the bulk drug substance should be nominated with a justification for its use. As of May 10, 2024, the FDA has not received a nomination for GS-441524. 
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Translation
To submit a nomination for the use of GS-441524 for office stock, see Nominations for Bulk Drug Substances for Compounding: (1) Office Stock Drugs for Use in Nonfood-Producing Animals or (2) Drugs for Use in Food-Producing Animals or Free-Ranging Wildlife Species.
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Issued by FDA Center for Veterinary Medicine.
For questions, Contact CVM.