Objectives: The objective of this study is to evaluate the efficacy and safety of long-term (64 weeks; 52-week extension of a 12-week study) baricitinib treatment in Japanese patients with active rheumatoid arthritis (RA) despite methotrexate therapy.
Methods: Patients (N = 145) with active RA were randomized to placebo, 1mg, 2mg, 4mg, or 8mg baricitinib for the first 12 weeks. During the 52-week extension period, patients on 4mg or 8mg baricitinib remained on the same dose and all other patients were re-randomized to 4mg or 8mg baricitinib. Most patients on 8mg baricitinib were switched to 4mg by week 64 (protocol amendment); data analysis was based on the treatment group at the beginning of the extension period.
Results: Increases in the American College of Rheumatology (ACR) response rates (ACR20, ACR50, and ACR70) observed during the first 12 weeks were maintained during the extension period, accompanied by improvements in ACR core components. At week 64, a large proportion of patients (>40%) had low disease activity. Most treatment-related adverse events were mild or moderate; herpes zoster was the most common reason (11/27 patients) for discontinuation.
Conclusions: The efficacy and safety profile of baricitinib was maintained during long-term treatment of Japanese patients with RA and background methotrexate therapy. Clinicaltrials.gov NCT01469013; Funding: Eli Lilly and Incyte.
Keywords: Arthritis, rheumatoid; Janus kinase; Japan; baricitinib; inflammation.