The effect of interferon-beta1a on relapses and progression of disability in patients with clinically isolated syndromes (CIS) suggestive of multiple sclerosis.

OBJECTIVES: In 85% of young adults with multiple sclerosis (MS), onset is a subacute clinically isolated syndrome (CIS) of the optic nerves, brain stem or spinal cord. The advent of disease-modifying treatments for MS has increased attention on early stages of the disease. Therefore, the aim of this study was to evaluate the effect of interferon on relapses and progression of disability in patients with a CIS.

PATIENTS AND METHODS: This randomized, clinical trial was conducted in 25 patients who presented with a CIS indicative of MS. They were evaluated in two groups: 11 patients who were receiving interferon-beta(1a) (Rebif, Serono) subcutaneous injections three times a week (group A), and 14 patients who were not receiving disease-modifying treatment (group B). The progression of disability was determined using the Kurtzke Expanded Disability Status Scale (EDSS) and the numbers of new relapses were recorded during 21 months of follow-up.

RESULTS: The mean numbers of new relapses and changes in EDSS at the end of study period were 0.68 (standard deviation [S.D.]=0.80) and -1.09 (S.D.=0.49), and 1.79 (S.D.=1.05) and -0.64 (S.D.=0.49) in groups A and B, respectively. Statistical analysis showed that disease-modifying treatment with interferon-beta(1a) may reduce relapses (P=0.007) and prevent progressive disability (P=0.034).

CONCLUSION: Interferon-beta(1a) significantly delayed progression to disability and incidence of new relapses.