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

Inhibition of the 3CLpro of FIPV with GC376 was effective under the conditions of this study in decreasing virus replication and causing remission of disease signs in cats with naturally occurring FIP outside of the CNS. However, sustained remissions in this study were more apt to occur in kittens <18 weeks of age presenting with acute onset wet FIP or in cats with dry FIP limited to a mesenteric lymph node and less likely to occur in cats greater than 18 weeks of age presenting with dry, dry-to-wet or ocular disease. Failure to achieve sustained remission was associated with either a high incidence of neurologic disease during or after treatment is stopped or to recurrence of abdominal lesions. Antiviral treatment seemed to slow the progression of neurologic disease but did not reverse it at the dosage employed in this trial. The reason for recurrence of extra-neurologic disease in the face of treatment was not determined but was not associated with mutations in the protease binding region.