Treatment with interferon beta-1b delays conversion to clinically definite and McDonald MS in patients with clinically isolated syndromes

Neurology. 2006 Oct 10;67(7):1242-9. doi: 10.1212/01.wnl.0000237641.33768.8d. Epub 2006 Aug 16.


Objective: To assess efficacy, safety, and tolerability of every-other-day interferon beta-1b treatment in patients with a first clinical event suggestive of multiple sclerosis (MS) (clinically isolated syndrome).

Methods: We conducted a multicenter, randomized, double-blind, placebo-controlled trial. Patients with a first clinical demyelinating event and at least two clinically silent brain MRI lesions were randomized to interferon beta-1b (IFNB-1b) 250 mug subcutaneously (SC) every other day (EOD) (n = 292) or placebo (n = 176), until clinically definite MS (CDMS) was diagnosed or they had been followed for 24 months.

Results: After 2 years, 45% of placebo patients had converted to CDMS (Kaplan-Meier estimate; primary outcome measure) and 85% fulfilled the McDonald criteria (co-primary outcome measure). Overall interferon beta-1b delayed the time to diagnosis of CDMS (p < 0.0001) and McDonald MS (p < 0.00001). Hazard ratios (95% CI) were 0.50 (0.36 to 0.70) for CDMS and 0.54 (0.43 to 0.67) for McDonald MS favoring treatment with IFNB-1b. Treatment was well tolerated, as indicated by the low rate of patients dropping out of the study before CDMS was reached (6.6% overall, 7.2% in the IFNB-1b group).

Conclusions: Interferon beta-1b 250 mug subcutaneously every other day delayed conversion to clinically definite multiple sclerosis, and should be considered as a therapeutic option in patients presenting with a first clinical event suggestive of multiple sclerosis.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Canada / epidemiology
  • Disease-Free Survival
  • Double-Blind Method
  • Europe / epidemiology
  • Female
  • Humans
  • Interferon beta-1b
  • Interferon-beta / therapeutic use*
  • Israel / epidemiology
  • Male
  • Multiple Sclerosis / diagnosis
  • Multiple Sclerosis / drug therapy
  • Multiple Sclerosis / epidemiology*
  • Multiple Sclerosis / prevention & control*
  • Placebo Effect
  • Prevalence
  • Risk Assessment / methods*
  • Risk Factors
  • Syndrome
  • Time Factors
  • Treatment Outcome


  • Interferon beta-1b
  • Interferon-beta