Teriflunomide, cognition and MRI: A longitudinal study.

Background: As cognitive impairment in multiple sclerosis (MS) is a frequent and disabling symptom, it is particularly important to identify treatments that have proven efficacy in this aspect of the disease. Several disease-modifying therapies for MS have been evaluated and shown to have a potential effect on cognition and its neurobiological correlates, but to date there is very little data on Teriflunomide (TRF). The aim of this study is to explore the influence of TRF on comprehensive cognitive function and its MRI correlations (global and focal brain volume) in relapsing-remitting multiple sclerosis (RRMS) after two years of therapy.

Methods: Twenty-four patients with RRMS were evaluated at baseline and after two years of treatment with BCcogSEP, a French translation of the Brief Repeatable Battery (BRB-N) including 3 additional tests. We explored the performance evolution for each test and correlation with MRI data for all patients. We also differentiated MS patients with and without cognitive impairment.

Results: After two years of treatment, an improvement is observed at the Selective Reminding Test for mean number of words (p = 0.044), learning (p = 0.018), and delayed recall (p = 0.002) and at GoNoGo task (p = 0.022). At MRI, the corpus callosum volume variation correlates positively with SRT total recall test (p = 0,047). Intergoup analysis shows that the evolution of group performance differs only for the SRT total recall test. The comparison of patients with or without cognitive impairment showed a clear difference in white matter substance volume (p = 0,003) and in the Percentage Brain Volume Change (p = 0,016).

Conclusion: Results suggest that TRF treatment in RRMS has a positive effect in cognitive function, and specifically on long term verbal memory and inhibition. Neuroimaging data suggest a link between cognition and global and focal white matter volume, particularly in the corpus callosum which is involved in anatomical disconnection syndrome and therefore brain plasticity capacities.