Multicentre, prospective, observational study on the effectiveness and safety of upadacitinib for active perianal fistulising Crohn’s disease in patients with prior anti-tumour necrosis factor failure: a study protocol
Abstract Background Perianal fistulising Crohn’s disease (pfCD) is a debilitating phenotype and remains a therapeutic challenge. Current guidelines recommend anti-tumour necrosis factor agents as first-line therapy for pfCD; however, there is still no consensus on the optimal pharmacological strategy once anti-TNF ther...