Novel TYK2 Inhibitors with an N-(Methyl-d3)pyridazine-3-carboxamide Skeleton for the Treatment of Autoimmune Diseases

Tyrosine kinase 2 (TYK2) mediates the interleukin-23 (IL-23), IL-12, and type I interferon (IFN)-driven signal responses that are critical in autoimmune diseases. Here, a series of novel derivatives with an N-(methyl-d3)pyridazine-3-carboxamide skeleton that bind to the TYK2 pseudokinase domain were designed, synthesized, and evaluated. Among them, compound 30 demonstrated more excellent inhibitory potency against STAT3 phosphorylation than the positive control deucravacitinib. In addition to JAK isoform selectivity, compound 30 exhibited good in vivo and in vitro pharmacokinetic properties. Furthermore, compound 30 was orally highly effective in both IL-23-driven acanthosis and anti-CD40-induced colitis models. Together, these findings support compound 30 as a promising candidate for therapeutic applications in autoimmune diseases.

Automated summary

In this study, a series of novel derivatives that bind to the TYK2 pseudokinase domain were designed, synthesized, and evaluated. Compound 30 showed excellent inhibitory potency against STAT3 phosphorylation, along with good JAK isoform selectivity, in vivo and in vitro pharmacokinetic properties, and high oral effectiveness in autoimmune disease models. These findings suggest that compound 30 is a promising candidate for therapeutic applications in autoimmune diseases.