The Clinical and Molecular Response of Pyoderma Gangrenosum to Interleukin 23 Blockade: Result from a proof-of-concept open-label clinical trial

Pyoderma Gangrenosum is a severe ulcerative disease with a great need for novel therapies. A major barrier to the development of novel therapies is a lack of understanding of disease pathogenesis. We present the results of a proof-of-concept open label clinical trial of IL-23p19 antagonism with Tildrakizumab ion Pyoderma Gangrenosum. Gene expression analysis identified pro-inflammatory genes associated with interferon responses and dendritic cell activity including IFI27, XBP1, SAA1 LGALS3 and STAT3 significantly downregulated in lesional tissue after 12 weeks of therapy. Immunohistochemistry confirmed reduction in IL-17A and IL-17 F positive cells as well as reduction in TNF-a, C5a and IL-1B positive cells in week 12 samples compared to baseline. Significant reduction in serum inflammation was observed via serum proteomics, with IL-8, IL-6, and CASP-8 levels reduced comparable to healthy controls at Week 12. Clinical outcomes demonstrated significant reduction in ulcer size, pain, itch and quality of life outcomes in line with the molecular findings. Differential expression of key inflammatory cytokines such as IL-8, CXCL5, PD-L1, SPP1 and MMP1 were observed in tissue and serum when stratified by clinical responders and non-responders. This data provides insights into the clinical relevance of alterations in molecular markers in pyoderma gangrenosum and the potential for the identification of clinically relevant biomarkers of disease activity.