Progress in understanding the safety and efficacy of Janus kinase inhibitors for treatment of rheumatoid arthritis.

INTRODUCTION: Treatment of rheumatoid arthritis (RA) has improved considerably following the advent of biologic disease-modifying anti-rheumatic drugs (DMARDs). However, these drugs require special storage and transportation. Janus kinase (JAK) inhibitors are oral synthetic DMARDs that inhibit the non-receptor tyrosine kinase family Janus kinase. Recently, many JAK inhibitors are being developed as new therapies for patients with RA. AREAS COVERED: In this article, we mainly review the efficacy and safety of JAK inhibitors currently under investigation. Tofacitinib has already been approved in 43 countries except in the EU. Results of three JAK inhibitors (baricitinib, decernotinib, and peficitinib) in phase III are consistent with that of tofacitinib. Tofacitinib and baricitinib were partially effective in patients who had an inadequate response to biological DMARDs. Expert commentary: JAK kinase inhibitors provide a new therapeutic approach for rheumatoid arthritis. Meanwhile, further studies are needed to determine their risk-benefit ratio and the most appropriate patients suitable for such therapy.