Thirty‐two cats with effusive or non‐effusive feline infectious peritonitis treated with a combination of remdesivir and GS‐441524

Abstract

BackgroundGS‐441524 has been successfully used to treat feline infectious peritonitis (FIP) in cats. However, the use of its prodrug, remdesivir, in combination with a PO GS‐441524 containing product for the treatment of FIP has not yet been described.ObjectivesDescribe treatment protocols, response to treatment and outcomes in cats with FIP treated with a combination of PO GS‐441524 and injectable remdesivir.AnimalsThirty‐two client‐owned cats diagnosed with effusive or non‐effusive FIP including those with ocular and neurological involvement.MethodsCats diagnosed with FIP at a single university hospital between August 2021 and July 2022 were included. Variables were recorded from time of diagnosis, and subsequent follow‐up information was obtained from the records of referring veterinarians. All surviving cats were observed for the entire 12‐week treatment period.ResultsCats received treatment with different combinations of IV remdesivir, SC remdesivir, and PO GS‐441524 at a median (range) dosage of 15 (10‐20) mg/kg. Clinical response to treatment was observed in 28 of 32 cats (87.5%) in a median (range) of 2 (1‐5) days. Twenty‐six of 32 cats (81.3%) were alive and in clinical and biochemical remission at the end of the 12‐week treatment period. Six of 32 cats (18.8%) died or were euthanized during treatment with 4 of the 6 cats (66%) dying within 3 days of starting treatment.ConclusionsWe describe the effective use of injectable remdesivir and PO GS‐441524 for the treatment of FIP in cats. Success occurred using different treatment protocols and with different presentations of FIP including cats with ocular and neurological involvement.

Retrospective study and outcome of 307 cats with feline infectious peritonitis treated with legally sourced veterinary compounded preparations of remdesivir and GS-441524 (2020–2022)

“…The legality of the drugs has facilitated access to data relating to direct veterinary input into the care of these cats. In agreement with previous studies 10,11,22,28 –33,40,42 reporting the use of varied (usually unregulated or illegal) nucleoside analogue preparations, in the present study, all three treatment protocols (ie, remdesivir alone, remdesivir then GS-441524 and GS-441524 alone) were highly effective in treating this previously fatal disease. An impressive 88.6% of cats were alive at the end of the initial treatment period, and 84.4% at the longest follow-up time point after completion of the initial treatment period (ie, at a median [range] of 180 [0–730] days).…”

“…One study limitation and interesting discussion point is that only 9.5% of cats in the study met the stringent diagnostic criteria that confirms a diagnosis of FIP, with only another one-third of cats (33.2%) having FCoV RNA detected in samples, leading to a diagnosis of FIP being ‘very likely’, the remainder being highly suspicious. This lack of definitive diagnosis in many cats is not dissimilar to other studies on the outcome of cats treated for FIP 10,11,22,29 –33,40 because, increasingly, financial resources for treatment are being prioritised over those to confirm the diagnosis, and the ability to perform further diagnostic testing in a case can be problematic due to access to testing or the condition of the cat. A positive response to treatment in suspected cases of FIP is sometimes used as strong diagnostic support for FIP.…”

“…38 Remdesivir has also been considered for FIP treatment in cats, 39 but its safety and efficacy have not been established in controlled peer-reviewed publications. However, favourable reports of the use of remdesivir to treat FIP in small numbers of cats have emerged, 40 –43 including the use of a regulated veterinary compounded ‘Specials’ product of injectable remdesivir (of known composition, as outlined above for GS-441524) legally available for cats in Australia (since November 2020), the UK (since August 2021) and some other countries (dependent on importation regulations, similar to GS-441524). As this is a drug that is registered for human use in almost all jurisdictions, its use in cats with FIP has been subject to fewer legal constraints than the unlicensed drug GS-441524, and various human formulations made under licence are widely available in many countries, including India, South Africa and Japan (R Malik, 2023, personal communication).…”

Optionen zur Therapie der felinen infektiösen Peritonitis – früher und heute

“…2/5 Katzen wurden aufgrund aufgetretener neurologischer Symptome euthanasiert. Zum Zeitpunkt der Veröffentlichung hatten 10 Katzen den 84-tägige Behandlungszyklus mit Remdesivir und GS-441524 erfolgreich abgeschlossen und befanden sich in Remission 77 .…”

Abdominal ultrasonographic findings of cats with feline infectious peritonitis: an update

“…Historically considered a fatal disease, recent research has revealed efficacy of new antivirals in FIP treatment, making an early diagnosis even more critical. [7][8][9][10][11][12] Immunohistochemistry (IHC) for the FCoV antigen in affected tissues is considered the gold standard for the diagnosis of FIP. 7 In the absence of a definitive diagnosis, background, clinical signs, routine laboratory tests and molecular analyses can be combined to establish a high index of suspicion of FIP.…”