Treatment of non-effusive feline infectious peritonitis using oral remdesivir or GS-441524: a randomized,...

ObjectivesFeline infectious peritonitis (FIP) is a fatal disease caused by feline coronavirus. The nucleoside analog GS-441524, the parent nucleoside of remdesivir, is the most commonly used FIP antiviral. Remdesivir is Food and Drug Administration approved to treat COVID-19 in humans and has been used primarily as an adjunctive treatment for FIP. Data on its efficacy as a first-line oral therapy, as well as its use to treat non-effusive FIP, remain limited. Therefore, this study compares the effectiveness of oral remdesivir vs GS-441524 as a first-line antiviral therapy for cats with non-effusive FIP in a prospective, randomized, double-blind, non-inferiority clinical trial. Furthermore, this study aims to bolster the literature supporting remdesivir use in these cats, anticipating potential future fluctuations in drug cost, availability and legal access.MethodsCats with non-effusive FIP were randomly assigned to receive either oral remdesivir (38-42 mg/kg, n = 10) or oral GS-441524 (18-22 mg/kg, n = 10) q24h for 84 days (12 weeks). Follow-up was conducted at 6 and 16 weeks, and response to therapy, survival and disease-free remission were assessed. Long-term follow-up was also obtained by contacting owners 1.5-2 years after conclusion of the study.ResultsAt week 16, 9/10 (90%) cats treated with remdesivir and 7/10 (70%) cats treated with GS-441524 were alive and in clinical remission. Remdesivir met the statistical criteria for non-inferiority, with a difference in disease-free survival of 20% (90% confidence interval -8.5 to +48.5). All deaths during treatment occurred within the first 11 days of the trial. Long-term follow-up revealed new onset of clinical signs and raised concerns for potential late relapse of disease in four cats (two in each group).Conclusions and relevanceThis study supports the hypothesis that oral remdesivir is non-inferior to GS-441524 for achieving survival and disease-free remission from FIP at 16 weeks. Given evolving global drug access and costs, remdesivir is a viable first-line option.