Immunotherapy to Reduce Anti-Inflammatory Drug Use in Atopic Dogs

In the Literature

Nagata M, Kozakai J, Yoshida A, et al. Immunotherapy using pullulan-conjugated Der f 2 allergen in canine atopic dermatitis: an anti-inflammatory agent-sparing approach. Vet Dermatol. 2024. doi:10.1111/vde.13315

The Research …

Canine atopic dermatitis (CAD) is an allergic skin disease that causes pruritus and inflammation. Clinical characteristics are typically associated with immunoglobulin E (IgE) antibodies; pathogenesis has been described as a T-cell–driven inflammatory skin disease that involves interaction of skin barrier abnormalities, allergen sensitization, and microbial dysbiosis.^1,2 Serum thymus and activation-regulated chemokine/chemokine ligand 17 (TARC/CCL17) is used as a biomarker for human atopic dermatitis and is preferentially expressed in the affected skin of dogs with CAD.^3,4

House dust mites are common environmental allergens. Der f 2 and Der p 2 from Dermatophagoides farinae and Dermatophagoides pteronyssinus, respectively, are major allergens in dogs with CAD and are difficult to avoid.⁵ Patients can exhibit clinical signs year-round.

Anti-inflammatory and/or immunomodulatory therapies, including corticosteroids, cyclosporine, and oclacitinib, are used to reduce acute and chronic signs of CAD. Allergen-specific immunotherapy (ASIT) is used to gradually increase exposure to causative extracts; traditional ASIT requires use over an extended period of time for efficacy.⁶ Pullulan, a large polysaccharide used in pharmaceuticals and food, is a product of the fungus Aureobasidium pullulans that can reduce IgE production and allergic reactions to environmental allergens when conjugated with Der f 2.⁵

This prospective study^a assessed the anti-inflammatory sparing effect of pullulan-conjugated recombinant Der f 2 (rDf2-P) subcutaneous immunotherapy, a commercially available product in Japan, administered to client-owned dogs (n = 21) with CAD for 1 year. Prior to immunotherapy, dogs were administered anti-inflammatory drugs for ≥4 weeks until clinical signs were mild, then maintained on the same administration regimen for 4 additional weeks. rDf2-P was then administered SC once weekly at increasing doses for 6 weeks, followed by a maintenance dose of 10 micrograms once monthly for 1 year. Medication scores, pruritus scores, Canine Atopic Dermatitis Extent and Severity Index (CADESI)-04, serum TARC/CCL17 concentrations, and other parameters were assessed at induction, every 3 months, and after 1 year of immunotherapy.

Significantly lower serum TARC/CCL17 concentrations were noted in dogs that had lower CADESI-04 scores (<17) compared with dogs that had higher scores (>17). More than 50% of patients experienced significant reductions in medication scores and clinical scores, translating to drug-sparing effects throughout the study.

^a This study was supported by Zenoaq, which provided Allermune HDM and measured serum IgE concentrations against rDf2-P and serum TARC/CCL17 concentrations.

… The Takeaways

Key pearls to put into practice:

• rDf2-P subcutaneous immunotherapy reduced anti-inflammatory drug doses by ≥50% in two-thirds of patients in this study, suggesting rDf2-P may be an effective proactive therapy for CAD.

• Administration of ASIT for at least 1 year under veterinary supervision and guidance can help determine efficacy.

• Further study of rDf2-P subcutaneous immunotherapy, specifically regarding dose adjustments required for seasonal fluctuations in patients with CAD, is needed.