Moving toward earlier treatment of multiple sclerosis: Findings from a decade of clinical trials and implications for clinical practice

• Trials of interferon beta and glatiramer acetate in patients with a first clinical event suggestive of multiple sclerosis.
• Implications on timing of treatment initiation.
• Early treatment in light of the evolution of the McDonald diagnostic criteria.

The first clinical presentation of multiple sclerosis (MS) is usually a single episode of typical symptoms and signs and is designated a “first clinical demyelinating event” (FCDE) or a “clinically isolated syndrome”. Patients with an FCDE who show ‘silent’ magnetic resonance imaging lesions are at high risk of further clinical events and therefore of meeting the criteria for the diagnosis of clinically definite MS (CDMS). Here we review five Phase III trials, in which treatment with the following disease-modifying drugs (DMDs) was initiated at this early stage: interferon beta (ETOMS, CHAMPS, BENEFIT, and REFLEX) and glatiramer acetate (PreCISe). Differences in the design of the trials and their patient inclusion criteria limit comparisons. However, the proportion of placebo-treated patients who developed CDMS within 2 years was 38–45% across studies, and this rate was significantly reduced by DMD treatment. Conversion to McDonald MS was reported by only two of the trials: BENEFIT (2001 criteria) and REFLEX (2005 criteria). Around 85% of placebo-treated patients developed McDonald MS by 2 years in each, and again a beneficial effect of DMD treatment was seen. Overall, these studies support early use of DMDs to treat patients with an FCDE who are at high risk of conversion to CDMS.