Atopic Dermatitis in Dogs
Atopic dermatitis (AD) is a genetically predisposed, inflammatory skin condition caused by hypersensitivity to environmental allergens such as pollen, house dust mites, and mold. Current research suggests that the disease arises from a complex interaction of genetic and environmental factors. Dogs with atopic dermatitis primarily show symptoms such as itching, redness, and chronic skin changes.
Studies on the treatment of AD are increasingly focusing on influencing the immune system and using newer medications such as Janus kinase inhibitors (JAK, or Jakinibs, e.g., oclacitinib, brand name Apoquel) as well as monoclonal antibodies that specifically target itching (e.g., lokivetmab). The active ingredient has been approved in the EU since 2017 and is injected once a month under the skin (subcutaneously).
Genetic Selection through Breeding
As part of research at Uppsala University, genes have been identified in dogs that are important for both the skin barrier and the immune defense. A significant finding is that a specific gene in dogs is a major risk factor for atopic dermatitis. Since the gene can be identified, it opens the way for targeted selection in the parent animals in dog breeding.
Tengvall, K., Sundström, E., Wang, C. et al. Bayesian model and selection signature analyses reveal risk factors for canine atopic dermatitis. Commun Biol 5, 1348 (2022). https://doi.org/10.1038/s42003-022-04279-8
Drug Therapy
Janus Kinase Inhibitors
Mechanism and use: Janus kinase inhibitors (JAK inhibitors) block specific enzymes involved in the signaling of cytokines, especially those that control the immune response and the inflammatory process. In atopic dermatitis, cytokines such as interleukin-2, -4, -6, and -31 play a key role by promoting inflammation and itching. Oclacitinib (brand name: Apoquel) is the most prominent JAK inhibitor currently used in veterinary medicine to treat dogs with atopic dermatitis.
Efficacy and safety: Oclacitinib works quickly and effectively by relieving itching and reducing inflammation within a few hours of administration. This makes it particularly useful in acute flare-ups. Studies have shown that oclacitinib is well tolerated, even with long-term use. Side effects are relatively rare and include mild Gastrointestinal disturbances and, in rare cases, a slight increase in the risk of infection due to the immunosuppressive effect.
Current research: Research is currently focused on the long-term safety of oclacitinib, specifically regarding the risk of infections and neoplastic diseases with chronic use. New JAK inhibitors are also being developed that have more specific effects and potentially fewer side effects.
Monoclonal Antibodies
Mechanism and use: Monoclonal antibodies are specifically developed proteins that recognize and neutralize specific molecules in the body. In atopic dermatitis, interleukin-31 (IL-31) is a key factor for itching. Lokivetmab (brand name: Cytopoint) is a monoclonal antibody that specifically targets IL-31, thereby effectively reducing itching.
Efficacy and safety: Lokivetmab has proven to be highly effective, especially in dogs with severe itching that does not respond adequately to other treatments. It offers a long-lasting effect (up to 4 weeks after a single injection), making it an attractive option for dogs with chronic AD. The safety of lokivetmab is generally considered high because it specifically targets a single cytokine and therefore has less impact on the general immune system.
Current research: Current studies are examining the long-term use of lokivetmab and its possible integration into multimodal therapy concepts that include a combination of JAK inhibitors, immunotherapies, and local (topical) treatments. It is also being investigated how lokivetmab can be used in earlier stages of the disease to prevent the progression of atopic dermatitis.
Comparison and Combination of Therapy Approaches
Combination therapies: An interesting area of current research is the combination of JAK inhibitors and monoclonal antibodies to maximize therapeutic efficacy and minimize side effects. By combining oclacitinib and lokivetmab, better control of symptoms can be achieved, especially in severe AD or in dogs that do not respond adequately to monotherapy.
Individualized therapy: The development of these targeted therapies makes it possible to individualize the treatment more. Depending on the severity of the disease, the response to different therapies, and the individual risk profile of the dog, veterinarians can specifically choose between these options or combine them.
Conclusion
The use of Janus kinase inhibitors and monoclonal antibodies represents a significant advance in the treatment of atopic dermatitis in dogs. These targeted therapies offer effective symptom control and have the potential to significantly improve the quality of life of affected dogs. Ongoing research focuses on further optimizing these therapies, ensuring their long-term safety, and developing new, even more specific treatment approaches. As a precaution, regular veterinary monitoring is recommended, as there are currently few long-term studies on the applications.
Sources
Marsella, R.: New Treatments and Validations for Atopic Dermatitis in Humans After Comparative Approach With Canine Models. In: Recent Advances in the Treatment of Atopic Dermatitis. DOI:10.5772/intechopen.1001478
Bizarro, A., Martins, A., Pinto, M., Fernandes, B., Pereira, H., Braz, B., & Lourenço, A. (2022). Protocolo alternativo com oclacitinib para dermatite atópica canina: Uma solução capaz de reduzir custos. Rev. Port. Imunoalergologia, 30, 31-41.
Ryguła I, Pikiewicz W, Kaminiów K. Novel Janus Kinase Inhibitors in the Treatment of Dermatologic Conditions. Molecules. 2023; 28(24):8064. https://doi.org/10.3390/molecules28248064
Sanchez, M.D., Bensignor, E.: Critically appraised topic: Benefits and risks of oclacitinib in treatment of allergic pruritus in dogs
Revue Vétérinaire Clinique
Volume 59, Issue 2, June 2024, Pages 72-88
