Efficacy of IDOR-1117-2520, a novel, orally available CCR6 antagonist in preclinical models of skin dermatitis.

Abstract

Background and purpose: The chemokine receptor CCR6 guides pathogenic T17 cells, implicated in autoimmune diseases including psoriasis, to sites of inflammation via the chemokine CCL20. Therefor, pharmacological inhibition of CCR6⁺ immune cell migration provides a novel therapeutic approach. Translatability of such an intervention has not yet been assessed in detail. We evaluated the translatability of the Aldara® mouse model induced skin inflammation to psoriasis, with particular focus on immune cell trafficking and assessed the efficacy of IDOR-1117-2520, a highly selective, potent and orally available CCR6 small inhibitor.

Experimental approach: Effects of IDOR-1117-2520 were investigated in the Aldara® and IL23 mouse models of skin inflammation using flow cytometry, RNA sequencing and transcriptome-based cell type deconvolution approaches to characterise immune cell migration patterns. These results were compared to human psoriasis transcriptomics data.

Key results: IDOR-1117-2520 dose dependently reduced infiltration of CCR6⁺ immune cells into inflamed skin, and was equally efficacious as IL-17 and IL-23 inhibition in models of skin inflammation. Pathway analysis showed molecular similarities in the immune response between human psoriasis and the Aldara® mouse model. IL-17/IL-23 pathway genes were expressed in both human psoriasis and the mouse model. CCR6 inhibition modulated multiple pathways associated with inflammation beyond the proximal IL-17/IL-23 pathway. A chemokine-chemokine receptor interaction map implicated CCL20-CCR6 as the dominant axis in recruiting pathogenic T17 cells in both the model and in human psoriasis.

Conclusion and implications: IDOR-1117-2520 could provide a promising novel targeted approach to treating psoriasis and, potentially, other autoimmune diseases involving the CCR6/CCL20 axis and the IL-17/IL-23 pathway. IDOR-1117-2520 is currently being evaluated in a clinical phase 1 trial (ISRCTN28892128).