Mirikizumab in ulcerative colitis: real-world evidence from an international two-center retrospective cohort study

Mirikizumab is a first-in-class IL-23p19 inhibitor, which is approved for the treatment of adults with moderate to severe ulcerative colitis (UC).

We aimed to assess the effectiveness and safety of mirikizumab in moderate to severe UC in a real-world cohort from two inflammatory bowel disease referral centers.

This was a two-center international retrospective observational cohort study.

This study aimed to assess the effectiveness and safety of mirikizumab for 12 weeks of induction. Clinical response and remission were defined as a reduction in the Simple Clinical Colitis Activity Index (SCCAI) of ⩾3 points, and SCCAI ⩽ 2, respectively. The primary outcome was the clinical remission rates after 12 weeks of induction.

We included 74 adult patients (58.1% female, 56.8% pan-colitis extent). Most patients (69/74, 93%) were previously exposed to a biological or a small-molecule therapy, and 39 (52.7%) started mirikizumab while on corticosteroids. By the end of induction, 8.1% discontinued therapy due to either lack of efficacy or an adverse event. Overall, clinical response, clinical remission, and corticosteroid-free-remission were 70.3%, 17.6%, and 16%, respectively. Week-12 clinical response and clinical remission rates were comparable between exposed and naïve patients for anti-tumor necrosis factor agents, ustekinumab, vedolizumab, and Janus-kinase inhibitors.

Mirikizumab was effective for inducing clinical response and well-tolerated in a substantial cohort of treatment-experienced patients with UC. This positions mirikizumab as a valuable option to the expanding therapeutic armamentarium for UC.