Etrasimod reduces circulating and mucosal inflammatory lymphocyte populations and alters innate immune and non-immune cell signatures in intestinal mucosa: ELEVATE UC phase 3 clinical data

Background and aims: Innate and adaptive immune cell dysregulation contributes to ulcerative colitis pathogenesis. The sphingosine 1-phosphate receptor modulator etrasimod showed efficacy in ulcerative colitis treatment in Phase 3 ELEVATE UC studies. Changes in circulating immune cells and mucosal cell types were characterized in etrasimod-treated patients with ulcerative colitis.

Methods

Blood (etrasimod n = 525, placebo n = 257 patients) and mucosal biopsies (etrasimod n = 411, placebo n = 200 patients) from patients in the ELEVATE UC trials were used to assess cellular and molecular changes for etrasimod versus placebo in clinical remitters and non-remitters using immunophenotyping, transcriptomic and proteomic techniques.

Results

Selective and partial reduction in circulating T- and B-cell subsets was observed for etrasimod versus placebo (Week 12), with greater effects on CD4+ T cells, including Treg and Th17 cells, than CD8+ T cells, and on naive T cells and T central memory cells than T effector memory cells, without difference between remitters and non-remitters. No significant effects on monocytes nor NK cell numbers were observed. Mucosal biopsies showed corresponding reductions in T- and B-cell subsets, myeloid cells and neutrophils accompanied by downregulation of interleukin-17 and interleukin-8 signaling in both tissue and blood, most prominently in remitters, where non-immune cell changes were consistent with tissue repair.