Bayer 18 is a tyrosine kinase 2 (TYK2) inhibitor (IC50 = 18.7 nM).[1] It is selective for TYK2 over JAK2, cyclin-dependent kinase 2 (Cdk2), and VEGFR2 (IC50s = 2,000, 1,790, and 3,520 nM, respectively).
References:
[1].Buchmann, B., Eis, K., Bothe, U., et al.Aminocabonylamino-substituted anilino-pyrimidine derivatives as Tyk inhibitors, their production and use as medicinal products(2010).