Introduction TOPIC (NCT00622700) was designed to evaluate teriflunomide in patients with a first clinical episode suggestive of multiple sclerosis (MS). Teriflunomide 14 mg reduced risk of relapse determining conversion to clinically definite MS by 42.6%, and of new relapse or magnetic resonance imaging lesion by 34.9% vs placebo. After study initiation, the 2005 McDonald criteria were revised, potentially allowing earlier MS diagnosis.

Methods The 2010 McDonald criteria were applied retrospectively. Patients who received teriflunomide 14 mg or placebo for ≤108 weeks were grouped according to fulfilment of 2010 criteria at baseline. Time to MS was analysed for those not fulfilling the 2010 criteria at baseline. Additional post hoc analyses will evaluate differences in outcomes based on baseline radiological characteristics of reclassified patients.

Results Patients receiving teriflunomide 14mg (n=214) or placebo (n=197) were analysed. For those not meeting the 2010 criteria (n=163), probability of conversion to MS was 54.1% (14 mg) and 74.4% (placebo). Teriflunomide 14mg reduced the probability of conversion to MS by 39.1% vs placebo. Data regarding time to MS based upon baseline radiological characteristics will be presented.

Conclusions Teriflunomide demonstrates a consistent treatment effect in patients with MS diagnosed according to differing diagnostic criteria. (Study supported by Genzyme, a Sanofi company).