2016 ACVIM Forum Research Abstract Program

A total of 92 cases were included. The mean dose of leflunomide was 1.79 AE 0.8 mg/kg/day. The median duration of the use of leflunomide was 23.5 weeks. Adverse events which could be related to leflunomide administration included diarrhea (3 of 92, 3.3%), lethargy (2 of 92, 2.2%), suspect blood dyscrasia (3 of 92, 3.3%), thrombocytopenia (2 of 31, 6.5%) and increased liver enzyme activities (1 of 16, 6.3%). Leflunomide was discontinued due to the possible adverse events in 6 dogs (6.5%). Significant dose differences between dogs with adverse events (n = 11, 2.6 AE 0.8 mg/kg/day) and dogs without adverse events (n = 81, 1.7 AE 0.8 mg/kg/day) were found (P < 0.001). The treatment response could be evaluated in 9 dogs with suspected IMPA, 7 dogs with IMTP, and 1 dog with CH. All of the 9 dogs with IMPA, 1 dog with IMTP and 1 dog with CH received leflunomide without administration of concurrent immunosuppressant drugs. Six of the dogs with IMTP received leflunomide with concurrent immunosuppressant drugs, the doses of which were unchanged when leflunomide was added to the treatment. Of these 17 dogs, 12 dogs (70.5%; 7 dogs with IMPA, 4 dogs with IMTP, 1 dog with CH) had an apparent positive response to the use of leflunomide. There was no significant difference (P = 0.18) in doses between dogs that responded to leflunomide (2.0 AE 0.8 mg/kg/ day) and those that did not respond (1.5 AE 0.4 mg/kg/day).