Upadacitinib as rescue therapy for acute severe ulcerative colitis and severe Crohn's disease - current knowledge and future directions.

Acute severe ulcerative colitis (ASUC) and acute severe Crohn's disease (CD) flare are potentially life-threatening conditions, for which treatment remains a clinical challenge. Currently available therapeutic options present limited efficacy, with a high rate of colectomy as the final-line treatment method. Therefore, new alternatives of rescue therapy in inflammatory bowel diseases (IBD) are constantly sought. Upadacitinib (UPA), a selective Janus kinase-1 (JAK1) inhibitor, has been approved for the treatment of moderate-to-severe ulcerative colitis (UC) and CD. Interestingly, the most recent data show an increasing off-label use of this medication in the management of acute severe colitis. We present a comprehensive review focusing on rescue therapy with UPA in IBD, both UC and CD. The article examines the outcomes of recent studies evaluating the effectiveness, safety, and tolerability of UPA treatment in adult patients with ASUC and severe CD flare, a new treatment strategy.