FIPLog was created in 2020 to help cat parents monitor their cats' progress through FIP treatment with GS-441524 and to standardize data collection.
At the time, GS-441524 was not approved or legally available. Veterinarians were largely unfamiliar with treatment, and many advised euthanasia. Cat owners had to source the drug through informal channels from overseas manufacturers, with no quality assurance.
This site helped legitimize GS-441524 as a viable treatment by collecting real-world data from hundreds of cats undergoing treatment. The data showed outcomes consistent with published clinical studies.
As of 2024, the landscape has fundamentally changed. The FDA announced enforcement discretion for compounded GS-441524, and multiple US compounding pharmacies now offer regulated, quality-tested oral tablets and suspensions. Veterinarians can legally prescribe GS-441524, and treatment no longer requires daily injections for most cats.
This site has served its purpose and is now archived as a historical resource.
This site was created and operated by Jeff Kessler, who successfully treated his cat, Cat Stevens, for FIP using GS-441524 in 2020.
Jeff has no involvement or affiliation with any companies selling or manufacturing GS-441524. He holds a PhD in energy and climate policy from the University of California and an MS in Chemical Engineering from the University of Colorado.
The site was operated free of charge, and no user data was ever sold. The site's code is available on GitHub.
In January 2020, Cat Stevens was diagnosed with Dry (non-effusive) FIP. After finding the Pedersen et al. (2019) paper, Jeff connected with FIP Warriors on Facebook and started GS-441524 treatment on February 19, 2020.
After one injection, Cat Stevens improved enough to leave intensive care. Treatment was challenging — 84 days of daily injections with an increasingly uncooperative cat. Churus and patience were essential.
Cat Stevens relapsed after the first round, likely due to undetected neurological involvement. A second round at higher dosage (10–15 mg/kg) was completed, and Cat Stevens was declared officially cured on October 30, 2020.
Today, cats like Cat Stevens can be treated with oral tablets from a compounding pharmacy — no injections needed!