Summary: This study aims to figure out how much etrasimod, a medication, ends up in breast milk after taking it for several days. To do this, the researchers will work with at least 8 healthy women who are breastfeeding. These women will take a 2 mg dose of etrasimod every day for 7 days while staying at the testing site. During the study, they won't be allowed to breastfeed their babies to keep the babies...

Summary: The purpose of this real world non-interventional study is to learn about the effects of etrasimod as treatment for patients with moderate to severe ulcerative colitis. Patients will be treated according to standard of care and will only be included in the study if etrasimod is the best treatment choice according to the treating physician. Additionally, patients have to be between 18 and 65 years ...

Summary: The purpose of this study is to determine the safety, efficacy, and pharmacokinetics (PK) of etrasimod for the treatment of moderately to severely active ulcerative colitis in adolescents (≥ 12 years up to \< 18 years of age). Participants who will complete the total 52-week treatment period will have the opportunity to continue in a Long-Term Extension (LTE) Period of up to 4 years (5 years after...