Efficacy of a 3C-like protease inhibitor in treating various forms of acquired feline infectious peritonitis

Pedersen, Niels C; Kim, Yunjeong; Liu, Hongwei; Galasiti Kankanamalage, Anushka C; Eckstrand, Chrissy; Groutas, William C; Bannasch, Michael; Meadows, Juliana M; Chang, Kyeong-Ok

A dramatic and progressive improvement in health was observed in 19/20 cats during the first 1-4 weeks of The time scale for treatment and clinical outcome of 20 cats entered into a field trial of GC376 protease inhibitor. Periods during which cats were treated are identified by solid lines. The date of the last day of treatment for the six cats that achieved a sustained clinical remission is indicated. Cat 21 was still on treatment at the time of writing. The remaining 13 cats succumbed to non-neurologic (FIP) or neurologic FIP (neuro-FIP) after being off primary or secondary treatments for 0-7 weeks treatment. The exception was cat CT16, which responded with a decrease in rectal temperature during the first 4 days of treatment. However, the fever returned and health continued to deteriorate over the next 23 days and the cat was euthanized. The fever (>102.5°F) in the other 19 cats disappeared within 24-48 h, associated with a parallel improvement in appetite, activity, growth and weight gain. Abdominal effusions were usually non-detectable within 2 weeks. The residual thoracic effusion remaining after initial therapeutic drainage was largely gone after 3 days in cat CT20. Renal masses in cats CT02 and CT13 also decreased rapidly in size and were non-palpable after 2 weeks. Enlarged mesenteric lymph nodes were somewhat slower to return to normal size. Palpable thickening of the colon and associated ileo-cecal-colic masses were the slowest to resolve and colonic signs persisted in cat CT03 in the face of treatment and a return to otherwise normal health. Jaundice, a frequent finding in younger cats with effusive FIP, slowly resolved over 2 weeks or more, in parallel with decreasing hyperbilirubinemia. Signs of ocular disease began to clear within 48 h and were gone by 1 week, regardless of initial severity ( Figure 3) .