GLPG3667 is an oral, reversible, and selective tyrosine kinase 2 (TYK2) inhibitor. It is being developed to treat inflammatory and auto-immune diseases. Biochemical assays showed that GLPG3667 displayed nanomolar potency on TYK2 with a selectivity over other JAK kinases >3-fold. In human PBMC, GLPG3667 showed comparable potency on the IFNα and IL-23 pathways (around 50 nM). Selectivity for TYK2 on the IFNα pathway was >14-fold and >19-fold toward the IL-2 and GM-CSF pathways in human PBMC and whole blood, respectively. Dermal ear inflammation in a mouse model of psoriasis driven by IL-23 was prevented by GLPG3667 with a minimal effective dose of 3 mg/kg given orally once daily. This effect was associated with a decrease in neutrophil infiltration and STAT3 phosphorylation at sites of inflammation. In healthy HV, GLPG3667 completely inhibited IFNα-induced STAT1 and STAT3 phosphorylation but did not impact IL-2- and GM-CSF-induced STAT5 phosphorylation.
