Background/Purpose:

Interleukin-2-inducible T-cell Kinase (ITK) and Bruton’s tyrosine kinase (BTK) are critical for B cells and T cells activation, and dysregulation of this process has been known to cause various immune-related diseases. Overexpression or hyperactivation of ITK/BTK has been shown to cause various autoimmune diseases. Existing BTK inhibitors has low clinical efficacy, which creates huge demands for treatment with higher efficacy. Thus, ITK and BTK dual target inhibitors may have synergistic therapeutic efficacy for the treatment of autoimmune diseases, including rheumatoid arthritis (RA). Therefore, we developed a novel ITK and BTK dual target inhibitor (DWP213388), which demonstrates higher pharmacological efficacy than existing selective BTK inhibitor.

Methods:

Inhibition of ITK and BTK enzyme activity and selectivity against Cys-family kinase group were evaluated by biochemical assay. Target occupancy in human T and B cells (Jurkat/Ramos) was measured by quantifying unbound ITK or BTK in ELISA-based assay using biotinylated-DWP213388, which binds to free active site of target following DWP213388 pre-incubation. Cellular assays for TCR or BCR stimulation-dependent activation and cytokine secretion were determined in human peripheral blood mononuclear cells (hPBMC).The efficacy of DWP213388 was investigated in collagen-induced arthritis (CIA) models in mouse and rat, in comparison with selective BTK inhibitor. To measure BTK occupancy, mouse spleen was extracted 2 hours and 24 hours after oral administration of DWP213388.

Results:

We developed a novel, potent dual target inhibitor, DWP213388, with ITK IC₅₀ value of 1.4 nM and BTK IC₅₀ value of 0.7 nM. More importantly, this compound is highly selective against ITK and BTK, yet has low affinity toward EGFR. DWP213388 potently occupied both of its targets at low concentration (ITK EC₅₀ value of 4.3 nM and BTK IC₅₀ value of 2.2 nM), which shows successful inhibition of TCR/BCR-dependent CD69 expression in T cells (54.4% inhibition at 100 nM) and B cells (58.2% inhibition at 10 nM). Unlike other selective BTK inhibitors, DWP213388 has an inhibitory effect on IL-17 production by Th17 (IC₅₀=29.1 nM). In mouse CIA model, treatment of DWP213388 improved arthritis in a dose-dependent manner, and the inhibitory effect was more potent than selective BTK inhibitor. In addition, histological damages in ankle and knee were markedly improved in mouse CIA model. The ED₅₀ value of DWP213388 is 0.38 mg/kg in mouse CIA model. Oral administration of DWP213388 at 1 mg/kg dose showed BTK occupancy in mouse splenocytes at 2 and 24 hours as 86% and 55%, respectively. BTK occupancy in mouse splenocytes shows strong correlation with the efficacy in mouse CIA model.

Conclusion:

We developed a novel, highly potent, and selective covalent inhibitor of ITK and BTK, DWP213388. We demonstrated that DWP213388 has potent in vitro and in vivo pharmacological activities compared to existing selective BTK inhibitor without affecting EGFR. These results suggest that DWP213388 may serve as a next generation therapeutic agent for autoimmune diseases, including RA.

« Back to 2018 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/discovery-of-dwp213388-a-potent-itk-and-btk-dual-target-inhibitor-with-excellent-efficacy-as-a-treatment-for-autoimmune-diseases/