A placebo‐controlled, double‐blind study evaluating the effect of orally administered polyunsaturated fatty acids on the oclacitinib dose for atopic dogs

Background Supplementation of polyunsaturated fatty acids (PUFA) enables dose reduction of prednisolone and ciclosporin in canine atopic dermatitis (cAD). Objective To determine if oral administration of PUFA reduces the dose of oclacitinib in cAD. Animals Twenty‐two client‐owned dogs with cAD receiving oclacitinib. Materials and Methods Dogs received a fish oil product (PUFA) or paraffin oil (placebo) for 16 weeks. Owners adjusted the oclacitinib dose according to daily pruritus assessments. On Day (D)0, D56 and D112, Canine Atopic Dermatitis Extent and Severity Index, fourth iteration (CADESI‐04), pruritus Visual Analog Scale (PVAS), quality‐of‐life score (QoL), Global Assessment (GA), quality‐of‐coat (QoC) and adverse events were recorded. Results Mean daily oclacitinib dose was significantly reduced in the PUFA group from 0.51 ± 0.20 mg/kg/24 h (D0) to 0.19 ± 0.14 mg/kg/24 h (D85–112; p < 0.00001) and not in the placebo group (D0: 0.70 ± 0.33 mg/kg/24 h; D85–112: 0.53 ± 0.35 mg/kg/24 h, p = 0.5422). CADESI‐04 did not change over time or differ between groups. PVAS was significantly lower in the PUFA group (2.8 ± 1.5) compared to placebo (4.2 ± 1.6) at D112 ( p = 0.0375). QoL and QoC improved only in the PUFA group (QoL: D0: 20 ± 7, D112: 12 ± 5, p = 0.0057; QoC: D0: 0 ± 0.5, D112: 1 ± 0.5, p = 0.0410). GA on D112 was higher in the PUFA group ( p = 0.008). No adverse events were observed. Conclusion Oral supplementation of PUFA allowed dose reduction of oclacitinib and improved PVAS, QoL, QoC and GA. The use of PUFA is recommended and was safe in the atopic study dogs receiving oclacitinib.