Efficacy of Der f 2/Zen 1‐LAMP1 Plasmid‐Based Vaccine Immunotherapy in Dogs With Atopic Dermatitis: A Proof‐of‐Concept Study

Background DNA‐based vaccination rapidly induces strong cellular and humoral immune responses, which may be enhanced by inclusion of lysosomal‐associated membrane protein‐1 (LAMP). Objectives This proof‐of‐concept study evaluated the efficacy and safety of a Der f 2/Zen 1‐LAMP‐based DNA vaccine immunotherapy in client‐owned dogs with nonseasonal AD sensitised to Dermatophagoides farinae (Df) . Animals Fifteen dogs positive for Df only and 20 dogs with reactivity to additional environmental allergens received either a low (0.5 mg/0.1 mL) or high (2 mg/0.4 mL) dose of the vaccine intradermally. Materials and Methods Four doses of vaccine were administered every 2 weeks. Pruritus, Canine Atopic Dermatitis Extent and Severity Index (CADESI)‐04, average daily medication scores (AvdMS) and adverse events (AE) were recorded over 24 weeks. Owner perception of treatment efficacy (OGATE) was assessed at the end. Results Pruritus and CADESI‐04 improved regardless of the sensitisation profile and the vaccine dose. After 24 weeks, despite a statistically insignificant reduction of AvdMS, 71%, 46% and 86% of dogs reached PVAS < 3.6, PVAS < 2 and CADESI‐04 < 10, respectively. There was no statistically significant effect of AvdMS on PVAS or CADESI‐04, meaning that the concurrently administered topical and/or systemic treatment(s) were unlikely to have been responsible for the observed PVAS and CADESI‐04 reduction. Twenty‐one owners (60%) rated the vaccine efficacy as good‐to‐excellent. No severe AEs were reported. Conclusions and Clinical Relevance These results of this proof‐of‐concept study support not only the safety of DNA vaccine immunotherapy in dogs with AD, but also its potential clinical benefits. A double‐blinded, ≥ 12 month long, controlled study with more subjects should follow to further confirm the true efficacy of this vaccine.