Abstract
BACKGROUND: Inhibition of the Janus kinase (JAK) pathway is a well-established option for canine atopic dermatitis (cAD). OBJECTIVE: To evaluate the efficacy and safety of ilunocitinib, a novel JAK inhibitor for the control of pruritus and skin lesions in client-owned dogs with cAD. ANIMALS: Two hundred sixty-eight dogs at 25 veterinary clinics. MATERIALS AND METHODS: In this randomised, double-masked, clinical trial, dogs received either ilunocitinib (n = 181; 0.6-0.8 mg/kg) or placebo (n = 87; 0.0 mg/kg) tablets once daily for 112 days. Pruritus was assessed by owners using a pruritus Visual Analog Scale (PVAS), while skin lesions were assessed by Investigators using the cAD Extent and Severity Index, 4th iteration (CADESI-04). Treatment success was defined as ≥50% reduction from baseline PVAS or CADESI-04 score on Day (D)28. Proportions of dogs achieving clinical remission from pruritus (PVAS < 2) or skin lesions (CADESI-04 < 10) also were assessed. RESULTS: At D28, 83% of ilunocitinib-treated dogs achieved treatment success compared to 31% of placebo-treated dogs (p < 0.001). A significantly higher proportion of ilunocitinib-treated dogs achieved ≥50% reduction in CADESI-04 scores at all time points (p < 0.001). The proportion of dogs achieving clinical remission PVAS or CADESI-04 scores was significantly higher in the ilunocitinib group starting on D7 and D14, respectively (p < 0.05). The 112-day ilunocitinib treatment was well tolerated. CONCLUSIONS AND CLINICAL RELEVANCE: Once daily ilunocitinib was well-tolerated and effective at rapidly reducing pruritus and resolving cAD-associated skin lesions. Clinical remission was achieved by two-thirds of dogs after 4 months of treatment. Ilunocitinib is safe and effective for managing clinical signs associated with cAD.