A Study to Investigate How Well Ravagalimab (ABBV-323) Works and How Safe it is in Participants With Moderate to Severe Ulcerative Colitis Who Failed Prior Therapy

Endoscopic Improvement is defined as Mayo endoscopic subscore of 0 or 1. Mayo endoscopic score is classified as 0=Normal or inactive disease; 1=Mild disease (erythema, decreased vascular pattern); 2=Moderate disease (marked erythema, absent vascular pattern, friability, erosions); 3=Severe disease (spontaneous bleeding, ulceration). Higher score indicates worsening of the disease. The number of responders is calculated based on the total number of participants and estimated response rate, rounding to a nearest whole integer.

Clinical remission per Adapted Mayo score is defined as stool frequency subscore (SFS) <=1, and not greater than baseline, rectal bleeding subscore (RBS) = 0, and endoscopic subscore <=1. The Adapted Mayo Score is a composite score of UC disease activity based on the following 3 subscores: Stool frequency subscore (SFS), scored from 0 (normal number of stools) to 3 (5 or more stools more than normal), Rectal bleeding subscore (RBS), scored from 0 (no blood seen) to 3 (blood alone passed), Endoscopic subscore confirmed by central reader, scored from 0 (normal or inactive disease) to 3 (severe disease, spontaneous bleeding, ulceration). The overall Adapted Mayo score ranges from 0 to 9 where higher scores represent more severe disease. The number of responders is calculated based on the total number of participants and estimated response rate, rounding to a nearest whole integer.

Clinical response per Adapted Mayo score is defined as the decrease from Baseline >= 2 points and >= 30%, PLUS a decrease in RBS >=1 or an absolute RBS <=1. The Adapted Mayo Score is a composite score of UC disease activity based on the following 3 subscores: Stool frequency subscore (SFS), scored from 0 (normal number of stools) to 3 (5 or more stools more than normal), Rectal bleeding subscore (RBS), scored from 0 (no blood seen) to 3 (blood alone passed), Endoscopic subscore, scored from 0 (normal or inactive disease) to 3 (severe disease, spontaneous bleeding, ulceration). The overall Adapted Mayo score ranges from 0 to 9 with higher scores representing more severe disease. The number of responders is calculated based on the total number of participants and estimated response rate, rounding to a nearest whole integer.

Clinical response per Partial Adapted Mayo score is defined as decrease from baseline >=1 points and >=30%, PLUS a decrease in RBS >= 1 or an absolute RBS <=1. The Partial Adapted Mayo Score is a composite score of UC disease activity based on the following 2 subscores: SFS, scored from 0 (normal number of stools) to 3 (5 or more stools more than normal); RBS, scored from 0 (no blood seen) to 3 (blood alone passed). The overall Partial Adapted Mayo score ranges from 0 to 6 with higher scores representing more severe disease. The number of responders is calculated based on the total number of participants and estimated response rate, rounding to a nearest whole integer.

Clinical Remission per full Mayo score is defined as Full Mayo score <=2 with no subscore > 1. The Mayo score is a tool designed to measure disease activity for ulcerative colitis. The FMS ranges from 0 (normal or inactive disease) to 12 (severe disease) and is calculated as the sum of 4 subscores (stool frequency, rectal bleeding, endoscopy [confirmed by a central reader], and physician's global assessment), each of which ranges from 0 (normal) to 3 (severe disease). Endoscopies were assessed by a central reader. Negative changes indicate improvement. The number of responders is calculated based on the total number of participants and estimated response rate, rounding to the nearest whole integer.

Endoscopic remission is defined as Mayo endoscopic subscore = 0. Endoscopies were assessed by a blinded central reader and scored according to the following scale: 0 = Normal or inactive disease; 1 = Mild disease (erythema, decreased vascular pattern); 2 = Moderate disease (marked erythema, lack of vascular pattern, any friability, erosions); 3 = Severe disease (spontaneous bleeding, ulceration). Higher score indicates worsening of the disease. The number of responders is calculated based on the total number of participants and estimated response rate, rounding to the nearest whole integer.