JAK inhibitors for inflammatory bowel disease: recent advances

Inflammatory bowel disease (IBD) commonly requires immunosuppressive treatments to induce and maintain durable remission. Janus kinase inhibitors (JAKis) are a novel group of orally administered, small molecule drugs that work by attenuating multiple cytokine signalling pathways to mediate dysregulated immune responses involved in the pathogenesis of IBD. Tofacitinib, filgotinib and upadacitinib have demonstrated efficacy against placebo and are licensed for the treatment of moderate to severe ulcerative colitis; upadacitinib is the only JAKi also currently approved for the treatment of Crohn's disease. Safety concerns stratified by age have led to class-wide regulatory restrictions for JAKi use across all inflammatory diseases. It is important for gastroenterologists managing patients with IBD to be aware of the key pivotal trial outcomes, to identify appropriate patients in whom to commence a JAKi, and to understand the safety considerations and ways to mitigate these risks in the patients they treat. This review provides a contemporaneous overview of this emerging therapeutic class and provides a practical guide for healthcare practitioners for initiating and monitoring JAKi in IBD.