IL17A and psoriasis: At present, interleukin-17 (IL-17) pathway antagonists in the market are mainly secukinumab (AIN457), ixekizumab (LY2439821), and brodalumab (AMG827), which were approved by the US Food and Drug Administration (FDA) in 2015, 2016, and 2017, respectively, for the treatment of moderate-to-severe psoriasis (10, 11).