Abstract: Background – Antiviral drugs such as GS-441524 and EIDD-2801 have been successful in treatment of feline infectious peritonitis (FIP), but only remdesivir is currently legally available in the USA; antiviral drugs can act synergistically with immunomodulatory treatments to improve patient outcome and survival in different viral diseases.Hypothesis/Objectives – To determine the efficacy of oral liposome-toll-like receptor (TLR3 and TLR9) agonist complex (LTC) as an adjunct treatment of cats being treated with EIDD-2801.Animals – Eleven client-owned cats.Methods – Placebo-controlled clinical trial in cats diagnosed with FIP. Results – Eleven cats diagnosed with FIP have completed 12 weeks of therapy with repeated bloodwork (7 cats in LTC and 4 cats in placebo group). Six cats were effusive (5 peritoneal and 1 pleural effusion), 1 cat had dry abdominal form and 4 cats had ocular FIP. At diagnosis, the median serum total protein was 8.3g/dL (IQR 7.5-9.8), median albumin 2.3g/dL (IQR 2.2-2.5), median globulins 6.0g/dL (IQR 5.0-7.4) and median albumin:globulin (A:G) ratio was 0.4 (IQR 0.3-05). At the 12 weeks recheck, the median serum total protein was 7.1g/dL (IQR 6.9-7.4), median albumin 3.4g/dL (IQR 3.2-3.7), median globulins 3.7/dL (IQR 3.4-4.1) and median A:G ratio was 0.9 (IQR 0.8-1.0). All cats are clinically doing well. The only reported side effect was hypersalivation in one cat treated with EIDD-2801 and placebo, all the other cats tolerated the therapy well. Conclusions and clinical importance – This preliminary data suggest that these medications are useful in successful treatment of FIP without severe side effects.
