title: Safety and Efficacy of Natalizumab in Japanese Patients with Relapsing-Remitting Multiple Sclerosis: Open-Label Extension Study of a Phase 2 Trial.
abstract: BACKGROUND
  The efficacy of natalizumab was evaluated in Japanese patients with relapsing-remitting multiple sclerosis (RRMS) in a 24-week, phase 2 bridging study. An open-label, 2-year extension study from this trial was conducted to assess the safety and efficacy of natalizumab treatment in Japanese patients.
  
  
  METHODS
  A total of 97 patients (43 previously on placebo; 54 previously on natalizumab) who had completed the bridging study were treated with 300 mg natalizumab every 4 weeks. Multiple sclerosis relapses, changes in Expanded Disability Status Scale (EDSS) scores, and adverse events were assessed at regular intervals. Anti-natalizumab and anti-JC virus (JCV) antibodies were measured.
  
  
  RESULTS
  After 2 years of natalizumab treatment, the mean adjusted annualized relapse rate was 0.30 (95% confidence interval [CI]: 0.18-0.52) among previously-on-placebo patients and 0.13 (95% CI: 0.05-0.29) among previously-on-natalizumab patients. The mean change in EDSS score from baseline to week 120 was -0.03 among previously-on-placebo patients and -0.18 among previously-on-natalizumab patients. In both groups, >90% of patients experienced ≥1 adverse event. Two previously-on-placebo patients developed persistently positive anti-natalizumab antibodies. Approximately 65% of all patients tested positive for anti-JCV antibodies at open-label treatment initiation. No deaths or progressive multifocal leukoencephalopathy cases were reported.
  
  
  CONCLUSIONS
  The efficacy and safety findings from this 2-year open-label extension study are comparable to and confirm the results of other clinical trials of natalizumab conducted in non-Asian patient populations, and provide longer-term evidence of efficacy and safety in Japanese patients.
  
  
  BACKGROUND
  ClinicalTrials.gov identifier NCT01416155.
  
  
  BACKGROUND
  Biogen.
authors.affiliation: Kansai Multiple Sclerosis Center, Kyoto, Japan. saida_takahiko@maia.eonet.ne.jp.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Saida
authors.affiliation: Department of Neurology, Graduate School of Medical Sciences, Fukuoka, Japan.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Kira
authors.affiliation: Hakusuikai Hatsuishi Hospital, Chiba, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Kishida
authors.affiliation: National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamura
authors.affiliation: Biogen Japan, Chuo-ku, Tokyo, Japan.
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Ohtsuka
authors.affiliation: Biogen Japan, Chuo-ku, Tokyo, Japan.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ling
authors.affiliation: Biogen Japan, Chuo-ku, Tokyo, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Torii
authors.affiliation: Biogen, Cambridge, MA, USA.
authors.forename: Nisha
authors.initials: N
authors.lastname: Lucas
authors.affiliation: Biogen, Cambridge, MA, USA.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Kuesters
authors.affiliation: Biogen, Cambridge, MA, USA.
authors.forename: Deb
authors.initials: D
authors.lastname: Steiner
authors.affiliation: Biogen Japan, Chuo-ku, Tokyo, Japan.
authors.forename: J T
authors.initials: JT
authors.lastname: Tibung
keywords: Efficacy; Japanese; Multiple sclerosis; Natalizumab; Open-label extension