GS-441524 in 17 cats with FeLV and/or FIV and suspected effusive FIP: survey data
Pathogens (Basel, Switzerland) · 2026
In plain language
The study gathered survey data from caretakers of 17 cats with FeLV and/or FIV who had received GS-441524 for suspected feline infectious peritonitis (FIP) with fluid buildup. Treatment schedules were changed, but these data do not identify the best schedule or show that the changes were effective. FIP was a presumptive diagnosis, and the protocols were neither standardized nor current. The ideal protocols and the influence of the amount of FeLV DNA integrated into cells remain unknown.
Scientific detail
The clinical study published in Pathogens in 2026 (doi: 10.3390/pathogens15030337) collected caretaker survey data on 17 FeLV- and/or FIV-positive cats treated with GS-441524 for presumptive effusive FIP. The claim describing the design and population is assigned evidence level C in the knowledge object. The reported design does not establish randomized allocation, diagnostic confirmation, or a controlled comparison. Although the population includes cats with FeLV, the article abstract does not separate all outcomes for cats positive only for FeLV.
Dosage increases were reported in 65% of cats in the cohort, and treatment was extended in 35%. This description of protocol modifications is assigned evidence level C; it does not identify an optimal dose, demonstrate the efficacy of dose escalation, or constitute a treatment recommendation.
The stated limitations include presumptive FIP diagnosis, survey-based data collection, noncurrent and unstandardized protocols, and use of unlicensed products. The source identifies a need for additional studies to determine ideal protocols and the impact of FeLV proviral load in retrovirus-positive cats with FIP. These remain open questions and do not support any specific protocol, dose, or duration.
What we know
A caretaker survey documented GS-441524 use in 17 cats with FeLV and/or FIV and presumptive effusive FIP, with dosage increases in 65% and treatment extension in 35%. Claims about the design and protocol modifications are assigned evidence level C. These data describe what was done; they do not demonstrate that the modifications were effective.
What we don't know
The ideal protocols and the impact of FeLV proviral load in this population have not been determined. The reported data do not establish an optimal dose or the efficacy of dose escalation. The article abstract does not separate all outcomes for cats positive only for FeLV, and FIP was a presumptive diagnosis.
Evidence
EvidenceLevel C — Preliminary evidenceConfidence 98/100
In the reported cohort, the average starting GS-441524 dosage was 7 mg/kg/day, with dosage increases in 65% of cats and treatment extension in 35%.
Excerpt verified in the source — verbatim, in the source's own language“The average starting dosage (7 mg/kg/d) was increased in 65% of cats, and treatment was extended in 35%.”
This reports dosing and protocol modification patterns in the surveyed cats. It does not identify an optimal dose, prove efficacy of dose escalation, or provide a treatment recommendation.
EvidenceLevel C — Preliminary evidenceConfidence 98/100
This study collected survey data from caretakers of FeLV- and/or FIV-positive cats treated with GS-441524 for presumptive effusive FIP.
Excerpt verified in the source — verbatim, in the source's own language“A survey was distributed to caretakers of cats with feline leukemia virus (FeLV) and/or feline immunodeficiency virus (FIV) that were treated with GS-441524 for presumptive effusive FIP based on survey responses.”
This establishes the survey-based design and population described by the source. It does not establish randomized allocation, diagnostic confirmation, or controlled comparison.
Open questionConfidence 99/100
Additional studies are needed to determine ideal protocols and the impact of FeLV proviral load in retrovirus-positive cats with FIP.
The source explicitly identifies unresolved research needs. This should not be read as evidence for any specific protocol, dose, duration, or clinical recommendation.
Provenance
Source: Clinical Features and Outcomes of Treatment for Effusive Feline Infectious Peritonitis with GS-441524 in Seventeen Retrovirus-Positive Cats.
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