Abstract 5133: Oxazolone induced atopic dermatitis mouse model using hIL-4/hIL-4Ra double knock-in mice, a preclinical mouse model for evaluating Dupilumab biosimilars
Authors: Yang Tao , Lu Rongfei , Xu Xiaofei , Zhang Likun , Wang Dawei , Feng Xinhe , An Xiaoyu , Wang Jessie (Jingjing) , He Xianfei , Edwards Carl K. 
Published: April 2023

Abstract
Background. Th2 cytokines (e.g. IL-4, IL-5, IL13) drive defined allergic reactions and various autoimmune and inflammatory diseases including atopic dermatitis (AD), asthma and rhinitis. IL-4Ra is a receptor shared by both IL-4 and IL-13, thus blocking of IL-4Ra could prevent both IL-4 or IL-13 mediated Th2 inflammatory response. Dupilumab (Dupixent) is a humanized anti-IL-4Ra monoclonal antibody which binds to human IL-4Ra and attenuates IL-4/IL-13 mediated Th2 inflammation. It has been approved for treating moderate to severe AD and asthma. However, since Dupilumab isn’t cross-reacting to mouse IL-4Ra, there is an unmet need for a robust mouse model to evaluate Dupilumab biosimilars at preclinical stages. In this study, we described an oxazolone induced AD model in hIL-4/hIL-4Ra double knock-in mice and its application to evaluate Dupilumab and its biosimilars.
Methods. The oxazolone induce AD mouse model was established in hIL-4/hIL-4Ra double knock-in mice by repeated topical applications of Oxazolone on ears. Oxazolone-induced mice received subcutaneous injection of Dupilumab at 25 mg/kg or 50 mg/kg. Dermatitis activity was assessed by measuring ear thickness, ear skin erosion, redness and scaling every other day. Serum were collected at the study end and IgE levels were measured by ELISA. In addition, spleens were also collected and their weights were compared. Ear were collected at study end and proceeded with cytokine analysis and pathology evaluation.
Results. Repeated topical application of oxazolone on mouse ears induced AD-like phenotypes including ear skin swelling, erythema and scaling, drastic elevation of IgE in serum, excessive production of human IL-4 cytokine as well as excessive inflammatory cell infiltration in ear skin, which suggests oxazolone is able to induce AD in this hIL-4/hIL-4Ra double knock-in mice. Subcutaneous injection of Dupilumab at two different doses levels, 25 mg/kg and 50 mg/kg successfully ameliorated ear skin swelling, erythema and scaling at the study end. In addition, Dupilumab at both dose levels significantly reduced the IgE level in serum and mitigated the inflammatory cell infiltration, e.g. eosinophil infiltration, in mouse ear. Furthermore, Dupilumab treatment significantly reduced mouse IL-6 and mouse KC/GRO levels in mouse ear. However, Dupilumab at both dose levels did not change the serum levels of human IL-4 as well as some other Th1 cytokines such as IFN-γ, IL-1β, TNF-α, etc. in mouse ear.
Conclusion. In summary, repeated challenge with Oxazolone in hIL-4/hIL-4Ra double knock-in mice resulted in the development of AD with a Th2-like hypersensitivity, mimicking the key features and pathology of the human disease, which responded to standard of care treatment Dupilumab. This provides a valuable translational model for the evaluation of future biosimilars of Dupilumab.
Citation Format: Tao Yang, Rongfei Lu, Xiaofei Xu, Likun Zhang, Dawei Wang, Xinhe Feng, Xiaoyu An, Jessie (Jingjing) Wang, Xianfei He, Carl K. Edwards. Oxazolone induced atopic dermatitis mouse model using hIL-4/hIL-4Ra double knock-in mice, a preclinical mouse model for evaluating Dupilumab biosimilars. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5133.