What is GS-441524, and Why Isn't It “Legal” (Still)?
June 2024 Update: GS-441524 oral formulations are now prescribable from various compounding pharmacies worldwide. However, please know that these compounds are still not considered legal. Click here to read what the FDA says about compounded GS-441524.
GS-441524 is a nucleoside analogue antiviral drug that Gilead Sciences developed. It is the primary plasma metabolite of the antiviral prodrug Remdesivir, which was created for human use. Remdesivir and GS-441524 were both effective in vitro against feline coronavirus strains that cause FIP. Remdesivir was never tested in cats, although it's used in other countries.
GS-441524 is an effective treatment for FIP and is widely used despite no official FDA approval due to Gilead's refusal to license this drug for veterinary use. This includes the new prescribable oral compounds.
The FDA is NOT to blame for the lack of an available, prescribable cure—although you will find people posting that they are. It's unfair to scrutinize parents who seek off-market FIP treatment (often at their veterinarian's recommendation). The ethical nature of their oath drives many veterinarians to advise their clients to find it by joining FIP support groups. Cat owners desperately want to save their beloved family pets and, in most instances, have to find them themselves.
Gilead Sciences holds the patent, aka "the key" to curing tens of thousands of cats globally. However, they chose not to proceed with FDA approval to make it legally available to prescribing veterinarians after the successful UC Davis 2017 drug trial. Here's their reasoning:
Gilead Sciences is known for its antiviral drugs for treating HIV/AIDS, hepatitis B and C, influenza, and COVID-19. Gilead refuses to license the drug for animal use, fearing its similarity to Remdesivir (originally developed to treat Ebola) would interfere with the FDA approval process.
Chinese companies and others worldwide started manufacturing the GS compound. **A word of caution: Not all GS are created equal. The Help For FIP® advisors can help guide owners to the safest GS nearby and always encourage your vet’s involvement. Be cautious of the attractive websites in a Google search or the persuasive scammers.
While the media zeroes in on the cost of this life-saving treatment, they neglect to report on the actual affordability and safety. Compared to 2019 and even 2023, the price of GS to the treating cat owner has drastically reduced, making it affordable to most owners.
As stated in the first paragraph, as of June 1, 2024, veterinarians can prescribe oral-only GS-441524 compounds (not injectables) under a specific FDA rule. While still illegal and unapproved, the FDA allows risk-free prescribing.
Please never assume that what you read online represents the current data—do your research. Please don't give up on treating your cat because you fear the cost is unaffordable. Please get in touch with Help for FIP® for guidance. No cat should go without treatment.
The FDA wishes to clarify that they have not approved the newer (as of June 2024) vet-prescribable compounded GS-441524 and Molnupiravir. This is the statement directly from their website. We urge people to please be mindful when talking about these drugs and to refrain from using terms like FDA-approved and legal—because they are not. In layman’s terms, the FDA is willing to “look the other way” and not enforce action on vets who opt to prescribe for their clients.
