There is no approved cure for cat's FIP (feline infectious peritonitis) yet. However, it is not necessary to put the cat to sleep - there is a way out of the situation.

The experimental liquid containing GS-441524 is very promising.
According to various estimates and based on previous experience, its effectiveness exceeds 96%

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6435921/
https://www.curefip.com/post/how-we-began-what-we-offer

The app is to facilitate the calculation of the current dose of GS-441524 solution
Calculations are based on the website https://pl.curefip.com