Advances in the use of Janus kinase inhibitors

Delineation of the JAK-STAT pathway critical for type 1/II cytokine signaling in late 1990s resulted in the development of multiple JAKi for IMIDs. Tofacitinib was the original JAK inhibitor approved in 2012 followed by baricitinib in 2017 and upadacitinib in 2019 with filgotinib and pefecitinib approved ex-US all for rheumatoid arthritis. Since the original approval JAK inhibitors have been approved for multiple IMIDs. In this manuscript, data from clinical trials evaluating JAK inhibitors for new IMID indications will be reviewed as well as an update on safety data from real world experience.