TYK2 and psoriasis vulgaris: So far, no clinical agents for the JH1 catalytic site of TYK2 have been reported to be selective despite considerable medicinal chemistry efforts, including Ropsacitinib (TYK2 kinase inhibitor) and Brepocitinib (TYK2/JAK1 dual inhibitor) that both entered Phase II clinical trial development against moderate to severe plaque psoriasis and other auto-immune disorders as orally administered drugs (NCT03895372, NCT02969018, NCT05076006, etc.)(29, 64, 65).