title: Interferon beta-1a for optic neuritis patients at high risk for multiple sclerosis.
abstract: OBJECTIVE
  To evaluate the effect of treatment with interferon beta-1a (Avonex) initiated at the time of a first episode of optic neuritis in patients at high risk for multiple sclerosis (MS).
  
  
  METHODS
  Randomized clinical trial.
  
  
  METHODS
  Prospective.
  
  
  METHODS
  Fifty clinical centers throughout the US and Canada.
  
  
  METHODS
  After the onset of a first episode of optic neuritis treated with intravenous and oral corticosteroids, 192 patients with brain magnetic resonance imaging (MRI) evidence of subclinical demyelination were randomly assigned to receive weekly intramuscular injections of 30 microg interferon beta-1a or placebo.
  
  
  METHODS
  The study outcomes were the development of clinically definite MS within 3 years of follow-up and brain MRI changes at 6, 12, and 18 months.
  
  
  RESULTS
  The rates of clinically definite MS and of a combined MS/MRI outcome were lower in the interferon beta-1a group than in the placebo group (adjusted rate ratios 0.58, 95% confidence interval 0.34 to 1.00; and 0.50, 95% confidence interval 0.34 to 0.73, respectively). Compared with the placebo group, on the 18-month brain MRI the interferon beta-1a group had a smaller change from baseline in T2 lesion volume (P =.02), fewer new or enlarging T2 lesions (P <.001), and a lower frequency of Gd-enhancing lesions (P <.001).
  
  
  CONCLUSIONS
  The clinical and brain MRI results of this trial support initiating interferon beta-1a treatment at the time of a first episode of optic neuritis occurring in patients at high risk for MS based on the presence of subclinical brain MRI lesions.
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology; D017050:Episode of Care; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007273:Injections, Intramuscular; D000068556:Interferon beta-1a; D016899:Interferon-beta / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000188:drug therapy*; D009902:Optic Neuritis / Q000175:diagnosis / Q000188:drug therapy*; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D016899:Interferon-beta; D000068556:Interferon beta-1a