The purpose of this study is to assess the efficacy, safety, and how the body interacts with an investigational drug in pediatric patients with Crohn's disease who have not had success with other medications. After study participants are screened, if eligible, they will receive the study drug. The study drug in this study is called Upadacitinib. While Upadacitinib is FDA-approved for use in adults with Crohn's Disease, it is investigational for children with Crohn's Disease.

The RE-EEN Smoothie Study is recruiting patients newly diagnosed with Crohn's Disease who are interested in using diet to help achieve disease remission. The purpose of the study is to evaluate the use of a whole-food based smoothie as Exclusive Enteral Nutrition for Crohn's Disease. In this study, participants will be randomly assigned to receive either a whole-food based smoothie, or formula as Exclusive Enteral Nutrition (EEN) therapy for Crohn's Disease. Participants will work closely with the study dietician to ensure that all of their nutritional needs are met during their participation in the study.