Effect of oral baricitinib on experimental cutaneous allergic and irritant reactions

Summary: Janus kinase inhibitors (JAKi) are becoming more commonly utilized in the treatment of dermatologic inflammatory and autoimmune diseases. Yet, the effect of JAKi on allergic and irritant skin reactions is an underdeveloped area of investigation. The goal of the present double-blinded placebo-controlled pilot study was to assess the ability of oral baricitinib (2mg/daily x 14 days) to treat experimental delayed-type hypersensitivity reactions (DTH) from <i>Candida albicans</i> antigen and irritant reactions from sodium laurel sulfate (SLS). Twenty-one healthy male subjects were recruited and were subjected to DTH testing with <i>Candida</i> antigen and SLS treatment. Measurement of DTH reactions by erythema and area of reaction by calipers along with pruritus and tissue RNA-seq by minimally invasive dermal biomarker patches were tested before and on repeat challenges following treatment with baricitinib or placebo. Oral baricinitib decreased the erythema responses and pruritus but not the area of induration by the second DTH challenge in comparison to placebo. The results of the tissue-seq indicated decreased inflammatory responses in both DTH and irritant skin reactions in response to JAKi. These pilot studies suggest that oral baricitinib could have efficacy in the management of both irritant and allergic contact dermatitis. Paul Montgomery¹, Christine M. Rapp^{2, 4}, Tobin Dickerson¹, Craig A. Rohan^{2, 4, 3}, Catherine Sherwin², Jeffrey B. Travers^{2, 4, 3} 1. Mindera Health, Vista, CA, United States. 2. Pharmacology & Toxicology, Wright State University Boonshoft School of Medicine, Dayton, OH, United States. 3. Dayton VA Medical Center, Dayton, OH, United States. 4. Dermatology, Wright State University Boonshoft School of Medicine, Dayton, OH, United States. Bioinformatics, Computational Biology, and Imaging