Mirikizumab Regulates Genes Involved in Ulcerative Colitis Disease Activity and Anti-TNF Resistance: Results From a Phase 2 Study

ABSTRACT Introduction: Mirikizumab, a monoclonal antibody targeting the p19 subunit of interleukin (IL)23, demonstrated efficacy and was well-tolerated in a phase 2 randomized clinical trial in patients with moderate-to-severe ulcerative colitis (UC) (NCT02589665). We explored gene expression changes in colonic tissue from study patients and their association with clinical outcomes. Methods: Patients were randomized to receive intravenous placebo or three mirikizumab induction doses. Patient biopsies were collected at baseline and Week 12, and differential gene expression was measured using a microarray platform and compared in all treatment groups to determine differential expression values between baseline and Week 12. Results: The greatest improvement in clinical outcomes and placebo-adjusted change from baseline in transcripts at Week 12 were observed in the 200 mg mirikizumab group. Transcripts significantly modified by mirikizumab correlate with key UC disease activity indices (modified Mayo score, Geboes Score, Robarts Histopathology Index) and include MMP1, MMP3, S100A8, and IL1B. Changes in transcripts associated with increased disease activity were decreased after 12 weeks of mirikizumab treatment. Mirikizumab treatment affected transcripts associated with resistance to current therapies, including IL-1B, OSMR, FCGR3A and FCGR3B, and CXCL6, suggesting that anti-IL23p19 therapy modulates biological pathways involved in resistance to anti-TNF and JAK inhibitors. Discussion: This is the first large-scale gene expression study of inflamed mucosa from patients with UC treated with anti-IL23p19 therapy. These results provide molecular evidence for mucosal healing from an extensive survey of changes in transcripts that improve our understanding of the molecular effects of IL-23p19 inhibition in UC.