• clinically isolated syndrome;
  • interferon treatment;
  • interferon beta-1a;
  • multiple sclerosis

Background –  A new treatment approach to multiple sclerosis (MS) is the initiation of interferon therapy in the early phase of the disease when a patient presents with clinically isolated syndrome.

Aims of the study –  The goal of this study was to assess the effect of early treatment on the risk of conversion to clinically definite MS in Iranian patients.

Methods –  Eligible patients had presented with a first episode of neurological dysfunction suggesting MS within the previous 3 months and had abnormal brain magnetic resonance imaging (MRI). Patients were randomly assigned to receive intramuscular interferon beta 1a 30 μg or placebo once a week for 3 years.

Results –  Of the 217 patients randomized, 202 patients completed the study; 104 received Avonex and 98 received placebo. Fewer patients converted to clinically definite multiple sclerosis in the treated group than in the placebo group during the study (36.6% vs 58.2%, P < 0.003). The number of active T2-weighted MRI lesions was significantly lower in the treated group.

Conclusions –  The results of our study, which are consistent with those from western studies, show that treatment at an early stage of MS delays conversion to definite MS and has positive effects on MRI outcomes.