In the CELEST Extension study, the results of which were published in , the researchers looked at the long-term efficacy, safety, and dose response of the immediate-release formulation of upadacitinib (Rinvoq), a JAK-1 inhibitor, in patients with moderate-to-severe Crohn's disease (CD) who were refractory to tumor necrosis factor (TNF) antagonists. A significant number of patients receiving 15-mg upadacitinib achieved clinical remission after 30 months of open-label treatment, suggesting that this dose is effective as a maintenance treatment for long-term use in patients, although one-third of patients lost response at or after week 4 and required dose escalation to 30 mg.