Two-Year Safety and Effectiveness of Peficitinib in Moderate-To-Severe Rheumatoid Arthritis: A Phase IIb, Open-Label Extension Study.

Introduction: Peficitinib is a novel orally bioavailable, once-daily Janus kinase (JAK) inhibitor approved in Japan for the treatment of rheumatoid arthritis (RA). This 2-year extension study of two global phase IIb trials investigated the long-term safety and effectiveness of peficitinib.

Methods: All eligible patients with moderate-to-severe RA including patients in the placebo group who participated in one of two global phase IIb trials ('with methotrexate' or 'without methotrexate') were included in this 2-year open-label extension study and were converted to peficitinib 100 mg once daily.