IL17A and psoriasis: Exploratory analyses from biomarker substudies of patients with moderate to severe psoriasis in the Efficacy and Safety Trial Evaluating the Effects of Apremilast in Psoriasis 2 (ESTEEM 2) study in North America and Europe, and in a phase 2b study in Japan, demonstrated reductions in key cytokines related to psoriasis pathology, namely 2 isoforms of interleukin (IL)‐17 (IL‐17A and IL‐17F), IL‐22 and tumor necrosis factor (TNF)‐α, with apremilast but not placebo.3