Effect of early interferon treatment on conversion to definite multiple sclerosis: a randomised study

Lancet. 2001 May 19;357(9268):1576-82. doi: 10.1016/s0140-6736(00)04725-5.


Background: Interferon beta reduces activity in multiple sclerosis as measured clinically and by magnetic resonance imaging (MRI). We assessed the effect of interferon beta-1a on the occurrence of relapses in patients after first presentation with neurological events, who are at high risk of conversion to clinically definite multiple sclerosis.

Methods: Eligible patients had had a first episode of neurological dysfunction suggesting multiple sclerosis within the previous 3 months and had strongly suggestive brain MRI findings. Patients were randomly assigned interferon beta-1a 22 microg or placebo subcutaneously once weekly for 2 years. Neurological and clinical assessments were done every 6 months and brain MRI every 12 months. Analyses excluded one patient assigned placebo who received no study injections.

Findings: 241 (78%) of 308 randomised patients received study treatment for 2 years; 278 (90%) remained in the study until termination. 57 (85%) of 67 who stopped therapy did so after conversion to clinically definite multiple sclerosis. Fewer patients developed clinically definite multiple sclerosis in the interferon group than in the placebo group (52/154 [34%] vs 69/154 [45%]; p=0.047). The time at which 30% of patients had converted to clinically definite multiple sclerosis was 569 days in the interferon group and 252 in the placebo group (p=0.034). The annual relapse rates were 0.33 and 0.43 (p=0.045). The number of new T2-weighted MRI lesions and the increase in lesion burden were significantly lower with active treatment.

Interpretation: Interferon beta-1a treatment at an early stage of multiple sclerosis had significant positive effects on clinical and MRI outcomes.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Double-Blind Method
  • Drug Administration Schedule
  • Europe
  • Female
  • Follow-Up Studies
  • Humans
  • Injections, Subcutaneous
  • Interferon-beta / administration & dosage*
  • Logistic Models
  • Magnetic Resonance Imaging / methods
  • Male
  • Multiple Sclerosis / diagnosis*
  • Multiple Sclerosis / drug therapy*
  • Multivariate Analysis
  • Physical Examination
  • Recurrence
  • Reference Values
  • Severity of Illness Index
  • Treatment Outcome


  • Interferon-beta