TNFi Plus Low-Dose Upadacitinib vs TNFi Intensification in Crohn's Disease With Suboptimal Response

This multicenter, randomized, controlled trial aims to evaluate the efficacy and safety of standard-dose tumor necrosis factor inhibitor (TNFi) plus low-dose upadacitinib compared with TNFi dose intensification in patients with moderate-to-severe Crohn's disease who have a suboptimal response to standard-dose TNFi therapy. Eligible participants are adults with active Crohn's disease receiving standard-dose infliximab or adalimumab who remain inadequately controlled despite ongoing treatment. Participants will be randomly assigned in a 1:1 ratio to either continue standard-dose TNFi with oral upadacitinib 15 mg once daily, or receive TNFi dose intensification according to the protocol. Clinical assessments will be performed at baseline and during follow-up, with the primary endpoint assessed at Week 14. The primary outcome is the proportion of participants achieving clinical remission, defined as a Crohn's Disease Activity Index (CDAI) score \<150 at Week 14. Secondary outcomes include clinical response, endoscopic response and remission, changes in inflammatory biomarkers such as C-reactive protein and fecal calprotectin, quality of life, and safety outcomes including adverse events and serious adverse events. Participants will continue follow-up after Week 14 to evaluate treatment durability and longer-term safety. This study is designed to determine whether a dual-target strategy with standard-dose TNFi plus low-dose upadacitinib provides superior short-term efficacy and acceptable safety compared with conventional TNFi intensification in Crohn's disease patients with insufficient benefit from standard-dose TNFi therapy.