Peficitinib for the treatment of rheumatoid arthritis: an overview from clinical trials.

INTRODUCTION: The treatment of rheumatoid arthritis (RA), a chronic, systemic, autoimmune disease, has been greatly advanced by the introduction of biologic disease-modifying antirheumatic drugs (DMARDs); however, many patients still fail to achieve disease remission. Peficitinib, an orally bioavailable inhibitor of the Janus kinase (JAK) receptor family, was approved in Japan in 2019 and Korea in 2020 for the treatment of RA. AREAS COVERED: This review provides an overview of JAK inhibitors currently marketed or in development; the pharmacodynamics and pharmacokinetics of peficitinib; and the efficacy and safety data for peficitinib from Phase 2b and 3 trials. EXPERT OPINION: Peficitinib has proven clinical efficacy in Asian patients (Japan, Korea, and Taiwan) with RA who have an inadequate response to conventional DMARDs. In Phase 3 trials, clinical improvements and prevention of joint destruction were demonstrated for both 100 mg and 150 mg once-daily peficitinib versus placebo, and treatment for up to 52 weeks was well tolerated. Safety signals, in particular the increased incidence of herpes zoster-related disease, appeared in line with other JAK inhibitors. Post-launch monitoring will establish the long-term safety and effectiveness of this drug, and further studies are necessary to determine its potential use in non-Asian populations.