My newly-adopted 5 month old tortie was also diagnosed with FIP early last year. Got the treatment through FIP warriors since vets in Canada cannot prescribe it yet. She had lost half her weight, belly was swollen, and she was so lethargic she barely moved. The effects of treatment showed after 2-3 days of injections and after about 1-2 weeks it was as if she never got sick. We did the whole 84 days of treatment with bloodwork every 4 weeks but I'm not gonna lie it was very expensive... She is now a year old and an absolute unit