Objective: Current antiviral therapy for feline infectious peritonitis (FIP) has limited availability and can be cost prohibitive. The nucleoside analogue EIDD-1931 is an effective inhibitor against feline infectious peritonitis virus (FIPV) serotype I & II in vitro. Our objective was to determine if EIDD-1931 is an effective treatment option for cats with naturally occurring FIP. Methods: Prospective clinical trial with nine client-owned cats diagnosed with effusive or non-effusive FIP including neurological involvement. Cats were administered EIDD-1931 orally twice daily for 12 weeks. A complete response was defined as resolution of all abnormalities associated with FIP. Clinical variables, hematology, biochemistry, and imaging findings were monitored during treatment and after discontinuing treatment. Results: Six cats with effusive FIP and three cats with non-effusive FIP (median age 1.0, range 0.5-7.9 years) were treated with EIDD-1931 (median dose 16.2 orally q12h, range 12.0-20.5 mg/kg) for 12 weeks in eight cats and 14 weeks in one cat. All cats showed a complete response to treatment. Adverse effects included transient neutropenia (three cats), elevated alanine transaminase (transient in three, persistent in one cat), broken whiskers (one cat) and suspected treatment induced relative hyporexia (six cats). Adverse effects were not dose dependent. Follow up was available for >12 months post treatment discontinuation. One cat relapsed on two occasions, responding to repeat treatment at escalating dosages before subsequent development of treatment resistant lymphoma resulting in euthanasia 545 days after study enrolment. No other relapse events or diseases were observed. Conclusions and relevance: EIDD-1931 administered at 15-20 mg/kg PO q12 for 12 weeks is a feasible treatment option for naturally occurring FIP. Adverse effects may be more common than treatment with GS-441524.
Kennedy et al. (Wed,) studied this question.