Efficacy and safety of oclacitinib for the control of pruritus and associated skin lesions in dogs with canine allergic dermatitis

BackgroundOclacitinib (Apoquel((R))) inhibits the function of a variety of pro-inflammatory, pro-allergic and pruritogenic cytokines that are dependent on Janus kinase enzyme activity. Oclacitinib selectively inhibits Janus kinase 1. Hypothesis/ObjectivesWe aimed to evaluate the safety and efficacy of oclacitinib for the control of pruritus associated with allergic dermatitis in a randomized, double-blinded, placebo-controlled trial. MethodsClient-owned dogs (n=436) with moderate to severe owner-assessed pruritus and a presumptive diagnosis of allergic dermatitis were enrolled. Dogs were randomized to either oclacitinib at 0.4-0.6mg/kg orally twice daily or an excipient-matched placebo. An enhanced 10cm visual analog scale (VAS) was used by the owners to assess the severity of pruritus from day0 to 7 and by veterinarians to assess the severity of dermatitis on days 0 and 7. Dogs could remain on the study for 28days. ResultsPretreatment owner and veterinary VAS scores were similar for the two treatment groups. Oclacitinib produced a rapid onset of efficacy within 24h. Mean oclacitinib Owner Pruritus VAS scores were significantly better than placebo scores (P<0.0001) on each assessment day. Pruritus scores decreased from 7.58 to 2.59cm following oclacitinib treatment. The day7 mean oclacitinib Veterinarian Dermatitis VAS scores were also significantly better (P<0.0001) than placebo scores. Diarrhoea and vomiting were reported with similar frequency in both groups. Conclusions and clinical importanceIn this study, oclacitinib provided rapid, effective and safe control of pruritus associated with allergic dermatitis, with owners and veterinarians noting substantial improvements in pruritus and dermatitis VAS scores.