title: Effect of interferon beta-1b in MS: assessment of annual accumulation of PD/T2 activity on MRI. UBC MS/MRI Analysis Group and the MS Study Group.
abstract: OBJECTIVE
  To determine whether the efficacy of interferon beta-1b (IFNbeta-1b) on lesion activity could be shown with annual analysis of MRI.
  
  
  BACKGROUND
  Clinical outcomes and MRI burden of disease changes in MS patients in a multicenter double-blind placebo-controlled 5-year trial of IFNbeta-1b have been reported, together with an analysis of 6-weekly MRI activity in a small subgroup during 2 years. MRI activity measurements based on annual scans have not been documented.
  
  
  METHODS
  Patients were randomized into three treatment arms: placebo, 1.6 mIU, and 8 mIU IFNbeta-1b self-administered subcutaneously every other day. Active lesions were identified as new, enlarging, or recurrent on proton density and T2-weighted MRI scans. Gadolinium was not used. An annual accumulation activity index was developed as an additional analysis of lesion activity.
  
  
  RESULTS
  During the 5 years, both high- and low-dose IFNbeta-1b groups showed a striking reduction in lesion annual accumulation activity on the activity index versus placebo (p = 0.001). Thirty-five percent of the high-dose patients and 29% of the low-dose patients were MRI inactive by this method of analysis, whereas only 16% of placebo patients were inactive (p = 0.001, placebo versus 8 mIU).
  
  
  CONCLUSIONS
  This analysis of the annual accumulation of lesion activity shows that the previously reported treatment effect seen on MRI scanning once every 6 weeks in a subcohort of the patients can also be seen on yearly scans. This annual accumulation activity analysis provides an independent MRI confirmation of a treatment and dose effect for IFNbeta-1b.
authors.affiliation: Division of Neurology, University of British Columbia, Vancouver Hospital and Health Science Center, Canada.
authors.forename: G J
authors.initials: GJ
authors.lastname: Zhao
authors.forename: R A
authors.initials: RA
authors.lastname: Koopmans
authors.forename: D K
authors.initials: DK
authors.lastname: Li
authors.forename: L
authors.initials: L
authors.lastname: Bedell
authors.forename: D W
authors.initials: DW
authors.lastname: Paty
mesh_terms: D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D000068556:Interferon beta-1a; D000068576:Interferon beta-1b; D016899:Interferon-beta / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D011446:Prospective Studies; D011522:Protons; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D011522:Protons; D000068576:Interferon beta-1b; D016899:Interferon-beta; D000068556:Interferon beta-1a