Effect of teriflunomide on gray and white matter brain pathology in multiple sclerosis using volumetric and diffusion-tensor imaging MRI measures

Objectives: To investigate the effect of teriflunomide on microstructural pathology in the gray matter (GM) and white matter (WM), as measured by changes in brain volume and diffusion-tensor imaging (DTI) in patients with multiple sclerosis (MS). Methods: 30 relapsing MS patients and 20 healthy controls (HCs) were enrolled in the study and followed prospectively for 12 months with clinical and 3T MRI examinations. Of those, 26 MS patients and 18 HCs completed the 6-month and 22 MS and 16 HCs patients the 12-month follow-up. Whole brain, GM, WM and thalamus volumes, and global and tract-based spatial statistics (TBSS) DTI measures of fractional anisotropy, mean, axial and radial diffusivity were obtained in the thalamus and normal appearing WM (NAWM). MRI differences between the groups were compared using non-parametric statistical methods due to sample size limitations, followed by post-hoc covariate-adjusted models. Results: At baseline, MS patients showed more severe brain volume and DTI measures compared to HCs (p < .05). At follow-up, no significant differences for brain volume and global and TBSS DTI measures between MS patients and HCs were found. No clinical progression or serious adverse events occurred in MS patients over the follow-up. Conclusions: MS patients did not significantly deteriorate over the follow-up in brain volume or thalamus/NAWM global or TBSS DTI measures, compared to HCs. This suggests that treatment with teriflunomide could potentially slow down accumulation of microstructural tissue damage in the GM and NAWM.