Continued Treatment With Mirikizumab effective in Patients With Ulcerative Colitis: Study

Mirikizumab is an antibody against the p19 subunit of interleukin 23 that has demonstrated clinical efficacy and was well tolerated following 12 weeks of induction treatment in a phase 2 trial of patients with moderate to severe ulcerative colitis. We present results of the open-label extended induction period in patients who did not initially respond to treatment with mirikizumab.

This study was a continuation of I6T-MC-AMAC, a double-blind trial, performed at 75 sites in 14 countries, in which patients with moderate to severe ulcerative colitis were randomly assigned to 12 weeks of induction therapy with 50 mg, 200 mg, or 600 mg mirikizumab or placebo. Patients without a clinical response (a 9-point decrease in Mayo subscore of ≥2 points and ≥35% from baseline and either a decrease of rectal bleeding subscore of ≥1 or a rectal bleeding subscore of 0 or 1) at week 12 were offered the opportunity to participate in an open-label, extended induction study for another 12 weeks, in which they received either 600 mg intravenous mirikizumab (n = 20) or, following a protocol amendment, 1000 mg intravenous mirikizumab (n = 64) every 4 weeks. At week 24, patients with a clinical response continued the extended maintenance period and received 200 mg subcutaneous mirikizumab. Endpoints included clinical remission (Mayo subscores of 0 for rectal bleeding, 0 or 1 with a 1-point decrease from baseline), clinical response, endoscopic remission (Mayo endoscopic subscore of 0), or endoscopic improvement (endoscopic subscore of 0 or 1), at study weeks 24 and 52. Data were analysed for patients who received mirikizumab or placebo during the induction phase of the study.