title: Efficacy and safety of the oral Janus kinase inhibitor peficitinib (ASP015K) monotherapy in patients with moderate to severe rheumatoid arthritis in Japan: a 12-week, randomised, double-blind, placebo-controlled phase IIb study.
abstract: OBJECTIVE
  To evaluate the efficacy, safety and dose response of a novel oral Janus kinase inhibitor, peficitinib (ASP015K), as monotherapy in Japanese patients with moderate to severe rheumatoid arthritis (RA).
  
  
  METHODS
  In a 12-week, double-blind study, 281 adult patients with RA with active disease not on concomitant disease-modifying antirheumatic drug therapy were randomised equally to once-daily placebo or peficitinib 25, 50, 100 and 150 mg. The primary endpoint was American College of Rheumatology (ACR) 20 response in the peficitinib treatment groups versus placebo at week 12.
  
  
  RESULTS
  Mean age was 53.0 years, 81.1% were female and 25.3% had previously used antitumour necrosis factor therapy. Peficitinib 50, 100 and 150 mg each showed statistically significantly higher ACR20 response rates compared with placebo, and response rates increased up to 150 mg with a statistically significant dose response. The total incidence of treatment-emergent adverse events (TEAEs) was similar between the placebo (64.3%) and peficitinib 25, 50, 100 and 150 mg groups (70.9%, 64.9%, 52.7% and 67.2%, respectively). TEAEs occurring more frequently in the peficitinib group compared with the placebo group included nasopharyngitis, increased blood creatine phosphokinase and diarrhoea. No cases of serious infections were reported. Herpes zoster occurred in four patients (two each in peficitinib 25 and 100 mg).
  
  
  CONCLUSIONS
  Treatment with peficitinib as monotherapy for 12 weeks in Japanese patients with moderate to severe RA is efficacious and showed acceptable safety profile. These findings support further developments of peficitinib for RA treatment.
  
  
  BACKGROUND
  NCT01649999; Results.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takeuchi
authors.affiliation: The First Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Computer and Information Science, Seikei University, Tokyo, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Iwasaki
authors.affiliation: Astellas Phama Inc., Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ishikura
authors.affiliation: Astellas Phama Inc., Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saeki
authors.affiliation: Astellas Phama Inc., Tokyo, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kaneko
mesh_terms: D000218:Adamantane / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000328:Adult; D018501:Antirheumatic Agents / Q000008:administration & dosage*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D053612:Janus Kinases / Q000037:antagonists & inhibitors*; D007564:Japan; D008297:Male; D008875:Middle Aged; D009536:Niacinamide / Q000008:administration & dosage / Q000031:analogs & derivatives*; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D009536:Niacinamide; D053612:Janus Kinases; C000608065:peficitinib; D000218:Adamantane
keywords: DMARDs (synthetic); Rheumatoid Arthritis; Treatment