A Maintenance Study of Mirikizumab in Participants With Moderately to Severely Active Ulcerative Colitis

Clinical remission at week 40 is defined as achieving a 9-point modified Mayo score for rectal bleeding=0, stool frequency=0 or 1 with ≥ 1 point decrease from baseline, and endoscopy=0 or 1 (excluding friability).

Stool Frequency Subscore, based on the participant's diary and scored from 0 (normal number of stools) to 3 (5 or more stools than normal); Rectal Bleeding Subscore, based on the participant's diary and scored from 0 (no blood) to 3 (blood only passed); Endoscopy Subscore, based on central reading of colonoscopy or sigmoidoscopy and scored from 0 (normal or inactive disease) to 3 (severe disease, spontaneous bleeding, ulceration).

Modified Intention-to-treat population (mITT): All randomized participants who received at least one dose of mirikizumab and who had a correctly measured Modified Mayo Score at baseline. Participants were analyzed according to the treatment arm to which they were randomized, regardless of the treatment actually received.

Endoscopic remission at week 40 is defined as achieving a Mayo endoscopic subscore of 0 or 1 (excluding friability) at Week 40. Endoscopy subscore is based on colonoscopy or sigmoidoscopy and scored from 0 (normal or inactive disease) to 3 (severe disease, spontaneous bleeding, ulceration).

Histologic remission was assessed using the Geboes histologic scoring system developed for assessment of histologic disease activity in ulcerative colitis. Remission was defined as Geboes histological subscore of 0 for grades: 2b (lamina propria neutrophils), and 3 (neutrophils in epithelium), and 4 (crypt destruction), and 5 (erosion or ulceration).

Symptomatic remission at week 40 is defined as a Mayo score for rectal bleeding=0, stool frequency=0 or 1 with ≥ 1 point decrease from baseline.

Stool frequency subscore, based on the participant's diary and scored from 0 (normal number of stools) to 3 (5 or more stools than normal).

Rectal bleeding subscore, based on the participant's diary and scored from 0 (no blood seen) to 3 (blood alone passed).

Endoscopic response at week 40 is defined as achieving at least a 1 point decrease from baseline in the Mayo endoscopic subscore.

Clinical response at week 40 is defined as a decrease in the 9-point modified Mayo score (MMS) [rectal bleeding, stool frequency and the endoscopic findings] inclusive of >= 2 points and >=30% from baseline with either a decrease of rectal bleeding subscore of >=1 or rectal bleeding subscore of 0 or 1.The MMS is a composite score of ulcerative colitis disease activity calculated as the sum of three subscores: Stool frequency subscore, based on the participant's diary and scored from 0 (normal number of stools) to 3 (5 or more stools than normal); Rectal bleeding subscore, based on the participant's diary and scored from 0 (no blood seen) to 3 (blood alone passed); Endoscopy subscore, based on colonoscopy or sigmoidoscopy and scored from 0 (normal or inactive disease) to 3 (severe disease, spontaneous bleeding,ulceration).

The IBDQ is a 32-item participant-completed questionnaire that measures 4 aspects of subjects' lives: symptoms directly related to the primary bowel disturbance, systemic symptoms, emotional function, and social function. Responses are graded on a 7-point. Likert scale in which 7 denotes "not a problem at all" and 1 denotes "a very severe problem." Scores range from 32 to 224; a higher score indicates a better quality of life. Least square (LS) Mean was calculated using analysis of covariance (ANCOVA) model for post-baseline measures: The ANCOVA model includes: treatment, baseline value, prior biologic or tofacitinib failure (yes/no), clinical remission status (yes/no) at AMAN Week 12, and region (North America/Europe/Other).

Fecal calprotectin is an indicator of inflammation in the colon with higher levels indicative of higher levels of inflammation. Least square (LS) Mean was calculated using ANCOVA model for post-baseline measures: The ANCOVA model includes treatment, baseline value, prior biologic or tofacitinib failure (yes/no), corticosteroid use (yes/no) at AMAN baseline, region (North America/Europe/Other), Clinical Remission status (yes/no) at AMAN Week 12.

The Urgency NRS is a single participant reported item that measures the severity for the urgency (sudden or immediate need) to have a bowel movement in the past 24 hours using an 11-point NRS ranging from 0 (no urgency) to 10 (worst possible urgency). Higher scores indicate more severe urgency. Least square (LS) Mean was calculated using mixed model repeated measures (MMRM) model for post-baseline measures: The MMRM model includes treatment, baseline value, visit, interaction of baseline value-by-visit, interaction of treatment-by-visit, prior biologic or tofacitinib failure (yes/no), baseline corticosteroid use (yes/no), clinical remission status (yes/no) at AMAN Week 12, and region (North America/Europe/Other).

Percentage of participants hospitalized for UC. Only hospitalizations associated with an adverse event with >=24 hours stay were recorded.

Clearance of mirikizumab was evaluated.