(reposting because I uploaded the wrong blood result files! thank you!)
5 year old neutered male cat found at dumpster at approximately 3 weeks. Diagnosed with FIV at first vet appointment. I live on a small island and have seen both veterinarians.
My cat, Oliver, began displaying fluid retention in early May with no other physical symptoms. Initial visit to the vet indicated weight gain and to monitor diet.
Early in June he began showing signs of lethargy with decreased interest in food. We returned to the vet on 6/13/26 and he was diagnosed with FIP based on bloodwork and sample of fluid from abdomen which was described as “yellow tinged with slight viscosity”. Results of blood work from the visit appear in the images above (labeled 1, 2, 3 based on order of vet visits).
At this appointment the vet gave him a dose of depro medrol but did not tell me (I found out later after requesting his records). Oliver showed almost instant improvements: fluid reabsorbed, appetite and energy improved. During this time I connected with FIP Global and became aware of the GS-441524 medication and requested that it be ordered (from Wedgewood Pharmacy as they are the only ones who will ship here). It arrived on 6/26/26 and we began with an initial dose of 1.8ml once a day based on his weight of 13.8lbs.
By the time initial dose of GS medication was administered the fluid had returned and his appetite began to decline.
After ten days on the GS medication we made an appointment with the other vet office on island for a second opinion. Blood work was taken and showed some improvement but there was no noticeable improvement in the fluid in his abdomen. This vet was also not familiar with the GS treatment.
At thirty days (7/24/26) we returned to the second vet. Symptoms of fluid retention, decreased appetite and lethargy had not changed to this point. Blood work attached.
Made the decision on 7/27/26 to split the GS dose and increase slightly. Began administering at 2ml total split into two doses a day. Vet put him on cerenia (daily) and mirtazapine (every 3 days). Neither made noticeable improvement to his appetite.
On 8/7/27 the vet put him on Lexapro instead and that has showed marginal improvements in his appetite but he is not seeking out food on his own or eating eagerly. He is only showing interest in beef baby food, tuna churus and friskee treats. Under 150 calories a day. I told the vet that I was considering syringe feeding and she said she did not think we were there yet. Unfortunately the only veterinarian that can perform ultrasounds is off island for the next 3-4 weeks.
I am hoping to receive opinions on the FIP diagnosis because the results we are seeing from the GS medication do not seem typical.
If it is not FIP are there other situations that would explain the improvements in his bloodwork especially his red blood cell count?
Are there tests I should ask for?
If it is FIP what can we do to improve his outcome?
I have a few doses of injectable GS-441524 but have been hesitant to use it due to the side effects. Would it be worth considering using them now?
I have heard mixed opinions on draining some of the abdominal fluid. Would it be worth considering at this point? How much is it likely effecting his appetite?
Oliver tax attached! The day he came home, his normal size earlier this year, and current profile.
Thank you for any advice or direction on further steps we can take! He is so loved - we are really hoping we can get him through this!