Three-Year Efficacy and Safety of Mirikizumab Following 152 Weeks of Continuous Treatment for Ulcerative Colitis: Results From the LUCENT-3 Open-Label Extension Study.

Background: Mirikizumab, a p19-directed interleukin-23 monoclonal antibody, has demonstrated induction of clinical remission at week 12 with maintenance through week 104 in patients with moderately-to-severely active ulcerative colitis (UC). Results are presented from the LUCENT-3 open-label extension study through week 152.

Methods: Of 868 LUCENT clinical trial program mirikizumab-treated induction patients, 544 were responders of whom 365 were rerandomized to mirikizumab maintenance. Of these, 324 completed week 52 and 316 entered extension treatment (286 week 52 responders; 179 week 52 remitters). Efficacy and safety outcomes are reported for mirikizumab-treated LUCENT-3 participants, including biologic-failed patients, with data for week 52 maintenance responders/remitters. Discontinuations or missing data were handled by nonresponder imputation, modified nonresponder imputation (mNRI), and observed cases.

Results: Using mNRI, 81.6% of week 52 responders demonstrated clinical response at week 152. Week 152 remission rates for week 52 responders included clinical (56.1%), corticosteroid-free (CSF; 54.5%), endoscopic (61.0%), histologic-endoscopic mucosal remission (HEMR; 52.6%), symptomatic (74.9%), and bowel urgency (BU; 58.6%). At week 152, 53.3% of week 52 responders achieved histologic-endoscopic mucosal improvement (HEMI) and 74.3% achieved BU clinically meaningful improvement (CMI). Among week 52 remitters, 85.4% showed a clinical response at week 152, with clinical (70.1%), CSF (68.9%), endoscopic (72.0%), HEMR (63.4%), symptomatic (81.4%), and BU (60.8%) remission. At week 152, among week 52 remitters, 64.0% of patients achieved HEMI and 75.6% achieved BU CMI. Stool frequency, rectal bleeding, BU, and abdominal pain score reductions from induction baseline to maintenance week 52 were sustained through week 152 for week 52 completers. Overall, in the safety population, 7.4% of patients reported severe adverse events (AEs); 5.3% discontinued treatment due to AEs. AEs of special interest included opportunistic infection (1.8%), hepatic disorders (3.2%), cerebrocardiovascular events (1.5%), and malignancy (0.3%). Patients with antidrug antibodies reduced over time from 23.6% in year 1 to 3.2% in year 3.

Conclusions: Symptomatic, clinical, endoscopic, histologic, and quality-of-life outcomes support long-term sustained benefit of mirikizumab treatment up to 152 weeks in patients with UC, including biologic-failed patients, with no new safety concerns.

Clinical trial registry: ClinicalTrials.gov: NCT03518086; NCT03524092; NCT03519945.