Efficacy and field safety of Ilunocitinib for the control of allergic dermatitis in client-owned dogs: A multicenter, double-masked, randomised, placebo-controlled clinical trial
Efficacy and field safety of ilunocitinib for the control of allergic dermatitis in client-owned dogs: A multicenter, double-masked, randomised, placebo-controlled clinical trial
Open access
In our edition of: Oct 2025
In our categories of: small animals
our summary:
Forster, S. et al. (2025) Efficacy and field safety of Ilunocitinib for the control of allergic dermatitis in client‐owned dogs: a multicenter, double‐masked, randomised, placebo‐controlled clinical trial Veterinary Dermatology.
The aim of this double-blinded randomised placebo-controlled study was to evaluate the efficacy and safety of ilunocitinib (a new Janus kinase inhibitor) in the control of pruritus in dogs with allergic dermatitis.
Client-owned dogs with a diagnosis of allergic dermatitis from 15 veterinary clinics in the United States were enrolled in the study and randomised in a 2:1 ratio to receive a once daily oral dose of either ilunocitinib or placebo tablets for 28 days. The study protocol was amended after six months to include an optional continuation phase (CP) to collect data on the safety and long-term efficacy of ilunocitinib. Pruritus was assessed by owners using a pruritus Visual Analog Scale (PVAS) and veterinary surgeon-assessed dermatitis VAS (DVAS) at day (D) 0, D1-7, D14 and D28. Treatment success was defined as ≥50% reduction from baseline PVAS on at least five of seven initial treatment days. Clinical remission from pruritus was considered achieved when PVAS <2.
A total of 306 dogs were included in the study (206 in the ilunocitinib group and 100 in the placebo group.) On D7 a higher percentage of ilunocitinib-treated dogs achieved treatment success compared to placebo dogs (25.4% compared to 7.7%). Beginning on D3 the proportion of dogs with a ≥50% reduction from baseline PVAS was significantly higher in the ilunocitinib group, by D28 a significantly higher percentage in the ilunocitinib group achieved clinical remission compared to placebo.
Reports of adverse events (AEs) in the ilunocitinib and placebo groups were similar at D7 (29.1% and 34%, respectively), D28 (47.6% and 49%) and D112 (59.7% and 53%). The most reported AEs were anorexia, lethargy, vomiting or nausea, diarrhoea, skin and appendage disorders and ear and labyrinth disorders,
Limitations of the study include the increasing disparity in the numbers in the two groups due to the large number of dropouts in the placebo group. There is a risk of sponsorship bias as the study authors are employees of Elanco Animal Health, manufacturers of ilunocitinib.
The study provides some evidence that ilunocitinib is safe and effective and offers an alternative treatment for the management of allergic dermatitis in dogs.
The following may also be of interest:
Veterinary Medicines Directorate (2025) Summary of product characteristics: Ilunocitinib Available from: https://www.vmd.defra.gov.uk/productinformationdatabase/files/SPC_Documents/SPC_3068704.PDF [Accessed 17 October 2025]
inFOCUS: 2023 AAHA management of allergic skin diseases in dogs and cats guidelines. [RCVS Knowledge] [Online] Available from: https://infocus.rcvsknowledge.org/2023-aaha-management-of-allergic-skin-diseases-in-dogs-and-cats-guidelines/ [Accessed 17 October 2025]
Cheung, B. Y. T. (2022). In dogs with atopic skin disease, is lokivetmab more effective than oclacitinib in reducing the score of a recognised scoring system? Veterinary Evidence, 7 (2). https://doi.org/10.18849/ve.v7i2.569
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