“Efficacy and Safety of the Nucleoside Analog GS-441524 for Treatment of Cats With Naturally Occurring Feline Infectious Peritonitis”, 2019-02-13 ():
Objectives: The aim of this study was to determine the safety and efficacy of the nucleoside analog GS-441524 for cats suffering from various forms of naturally acquired feline infectious peritonitis (FIP).
Method: Cats ranged from 3.4–73 months of age (mean 13.6 months); 26 had effusive or dry-to-effusive FIP and 5 had non-effusive disease. Cats with severe neurological and ocular FIP were not recruited. The group was started on GS-441524 at a dosage of 2.0 mg/kg SC q24h for at least 12 weeks and increased when indicated to 4.0 mg/kg SC q24h.
Results: 4⁄31 cats that presented with severe disease died or were euthanized within 2–5 days and a 5th cat after 26 days. The 26 remaining cats completed the planned 12 weeks or more of treatment. 18 of these 26 cats remain healthy at the time of publication (OnlineFirst, February 2019) after one round of treatment, while 8 others suffered disease relapses within 3–84 days. 6 of the relapses were non-neurological and two neurological. 3⁄8 relapsing cats were treated again at the same dosage, while 5 cats had the dosage increased 2.0 → 4.0 mg/kg q24h. The 5 cats treated a second time at the higher dosage, including one with neurological disease, responded well and also remain healthy at the time of publication. However, one of the 3 cats re-treated at the original lower dosage relapsed with neurological disease and was euthanized, while the two remaining cats responded favorably but relapsed a second time. These two cats were successfully treated a third time at the higher dosage, producing 25 long-time survivors. One of the 25 successfully treated cats was subsequently euthanized due to presumably unrelated heart disease, while 24 remain healthy.
Conclusion: GS-441524 was shown to be a safe and effective treatment for FIP. The optimum dosage was found to be 4.0 mg/kg SC q24h for at least 12 weeks.