The main purpose of this study is to evaluate the safety and effectiveness of LY4268989 when compared to placebo in adult participants with moderately to severely active ulcerative colitis (UC). The study drug will be administered orally.
The study will last up to approximately 108 weeks, excluding screening.
Have had an established diagnosis of ulcerative colitis (UC) for ≥3 months prior to randomization, which includes endoscopic evidence of UC
Have moderately to severely active UC defined by a Modified Mayo Score (mMS) of 5 to 9 with an Endoscopic Score (ES)≥2 confirmed by central reader and rectal bleeding (RB)≥1
Have evidence of UC extending proximal to the rectum
Have documented evidence of having had a surveillance colonoscopy within 1 year, or according to local guidelines, to evaluate for polyps, dysplasia, or malignancy, prior to randomization, if the participant has a history of UC symptoms for more than 8 years
Have a current diagnosis of
Crohn's disease
Inflammatory Bowel Disease (IBD unclassified) (formerly known as indeterminate colitis), or
primary sclerosing cholangitis