Efficacy and safety of peficitinib in rheumatoid arthritis.

Peficitinib is a Janus kinase (JAK) inhibitor, newly developed and approved in Japan. In contrast to other JAK inhibitors, it is a unique pan-JAK inhibitor, demonstrating inhibition of all JAKs. In patients with rheumatoid arthritis with an inadequate response to previous disease-modifying anti-rheumatic drugs, the efficacy of peficitinib (100 mg and 150 mg) has been confirmed with a comparison to placebo in Phase 2b and 3 trials conducted in Asia. Reportedly, peficitinib was well tolerated for 52 weeks during the trial duration, as well as for the next few years in a subsequent, ongoing long-term extension study. Safety signals, especially, the increased risk of herpes zoster was comparable with other JAK inhibitors.