This study aims to see if a drug called **tilpisertib fosmecarbil**, which was once called GS-5290, can help people with **ulcerative colitis** (UC). Ulcerative colitis is a condition where the large intestine becomes inflamed. Participants will either get the drug or a **placebo** (a pill with no medicine) to compare results. The main goal is to see if the drug helps with symptoms by Week 12.

• The study lasts 12 weeks with regular check-ups.
• Participants need to be 18 to 75 years old.
• People with certain infections or other specific health issues cannot join.

To join, you must have had UC for at least 90 days and have tried other treatments before. People who have other similar diseases or infections can't join. If you meet the requirements, you'll need a special test called a colonoscopy, where doctors look inside your colon with a camera. This study helps us learn if tilpisertib fosmecarbil works to make people with UC feel better.