Interleukin-17 Antagonists in the Treatment of Psoriasis

Background: Psoriasis is a chronic, immune-mediated inflammatory skin disorder of unknown etiology. Interleukin (IL)-17a, a key product of the recently identified Th17 cell subset, has been found to play a critical role in the immunopathogenesis of psoriasis. IL-17 antagonists are a new class of biological agent currently in development for psoriasis that selectively inhibit IL-17a activity. Objective: This review aims to summarize the current efficacy data from phase II randomized controlled trials of the IL-17 antagonists brodalumab, ixekizumab, and secukinumab for the treatment of moderate to severe psoriasis. Conclusion: Patients treated with IL-17 antagonists achieved marked reduction in psoriasis disease severity as demonstrated by the Psoriasis Area and Severity Index (PASI) 75 response rates. A sizable proportion of patients treated with brodalumab and ixekizumab achieved unprecedented clinical clearance of their psoriasis (PASI > 90). These encouraging results demonstrate the efficacy of these agents and validate the pro-inflammatory role of IL-17 in the pathophysiology of psoriasis.