Effectiveness of Ozanimod in Patients With Steroid-Dependent Ulcerative Colitis

This study is looking at how well ozanimod (a pill approved for ulcerative colitis) works in real-world patients who depend on steroids to manage their symptoms. Researchers are comparing ozanimod to another medication called azathioprine in people who cannot stop taking steroids without their colitis flaring. **You may be eligible if...** - You are 18 or older - You have ulcerative colitis and are steroid-dependent (meaning you cannot taper off steroids without your symptoms worsening) - You are starting treatment with ozanimod or azathioprine - You are on at least 30mg of oral steroids at the time of starting the new treatment **You may NOT be eligible if...** - You have Crohn's disease rather than ulcerative colitis - You have already been on ozanimod or azathioprine - You have certain heart conditions (like low heart rate or recent heart attack) - You have an active serious infection Talk to your doctor to see if this trial is right for you.