JAK Inhibitors for Atopic Dermatitis: An Update.

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases. AD is driven by barrier dysfunction and abnormal immune activation of T helper (Th) 2, Th22, and varying degrees of Th1 and Th17 among various subtypes. The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and spleen tyrosine kinase (SYK) pathways are involved in signaling of several AD-related cytokines, such as IFN-γ, IL-4, IL-13, IL-31, IL-33, IL-23, IL-22, and IL-17, mediating downstream inflammation and barrier alterations. While AD is primarily Th2-driven, the clinical and molecular heterogeneity of AD endotypes highlights the unmet need for effective therapeutic options that target more than one immune axis and are safe for long-term use. The JAK inhibitors, which target different combinations of kinases, have overlapping but distinct mechanisms of action and safety profiles. Several topical and oral JAK inhibitors have been shown to decrease AD severity and symptoms. A review of the JAK and SYK inhibitors that are currently undergoing evaluation for efficacy and safety in the treatment of AD summarizes available data on a promising area of therapeutics and further elucidates the complex molecular interactions that drive AD.