Publications

Peficitinib (ASP015K) is a novel orally bioavailable JAK inhibitor in development for the treatment of RA. It inhibits JAK1, JAK2, JAK3 and Tyk2 enzyme activities and has moderate selectivity or JAK3 inhibition.Here the authors report the findings of a 12-week, randomized, double-blind, placebo-controlled phase IIb study evaluating efficacy, safety and dose response of peficitinib (25, 50, 100, or 150 mg) as once-daily oral monotherapy in Japanese patients with moderate to severe RA. The primary efficacy endpoint was ACR20 response at Week 12; secondary endpoints included ACR50/70 responses, mean change in CRP level from baseline, mean change from baseline in DAS28-CRP, and percentage of patients achieving DAS-CRP <2.6,DAS28-CRP <3.2 or DAS28-ESR 2.6.A statistically significant dose response was observed for ACR response at Week 12. The results of the secondary efficacy variables supported this, with the peficitinib 100 and 150 mg groups showing a statistically significant improvement in secondary outcomes. Furthermore, peficitinib also appeared to improve the daily life activities of RA patients, and it showed an acceptable safety profile over 12 weeks.