Patients with clinically isolated syndrome (CIS) who were treated with interferon ß-1b (IFN) show long term benefits of early treatment (initiation within 2 years of diagnosis.) After 15 years, patients who were treated upon diagnosis of CIS (n = 161) or within 2 years of diagnosis (n = 100; mean time to treatment 1.53 years) were re-evaluated clinically and with brain MRI. Early intervention reduced the risk of developing MS and both groups showed little or no disease progression as indicated by low EDSS, supporting the value of initiating treatment with IFN at or shortly after CIS.
The annualized relapse rate for all patients was 0.2083 over 15 years, and those who had treatment upon diagnosis had a 15.7% lower risk of relapse than patients whose treatment began later (upon a second clinical episode or 2 years after the study began) (P = .1008). Estimated conversion to multiple sclerosis (MS) by year 15 was 69.8% with a 30.5% lower risk for those treated upon diagnosis of CIS vs those treated later (P = .029). In the overall cohort, the mean score on the Expanded Disability State Scale was 2.5.
A cohort of 261 patients who were enrolled in a trial and randomly assigned to receive IFN or placebo have now been followed for 15 years. Patients who had a relapse while on placebo were switched to IFN and at 2 years, all patients were switched to INF. Blinded prospective evaluations were done every 5 years and at 15 years, all patients were asked to complete a comprehensive re-evaluation. These data were presented at the American Conference on Treatment and Research in MMS (ACTRIMS) conference in Dallas, TX February 28-March 1.