Basal vitamin D levels and disease activity in multiple sclerosis patients treated with fingolimod

L. Ferre’, F. Clarelli, G. Sferruzza, M. A. Rocca, E. Mascia, M. Radaelli, F. Sangalli, G. Dalla Costa, L. Moiola, M. Aboulwafa, F. Martinelli Boneschi, G. Comi, M. Filippi, V. Martinelli, F. Esposito

Several studies have shown an association between 25-hydroxyvitamin D (25[OH]D) levels and multiple sclerosis (MS) susceptibility and/or level of disease activity in patients treated with first line drugs. To investigate whether baseline 25[OH]D values could influence disease activity also during treatment with the second-line drug fingolimod (FTY). We enrolled 176 MS patients who started FTY at the San Raffaele Hospital (OSR) MS center with available 25[OH]D measurement at the time of treatment start. We then prospectively followed them for 2 years with periodic clinical examinations and MRI scans. We found no linear correlation between baseline 25[OH]D levels and annualized relapse rate (ARR) or time to first relapse. However, we observed that patients with serum 25[OH]D ≥ 100 nmol/l showed a lower number of Gd+ and combined unique activity (CUA) lesions at baseline compared to patients with the lowest 25[OH]D levels (less than 50 nmol/l, p value < 0.05). Moreover, they showed fewer CUA lesions at 2-year follow-up also when accounting for baseline level of disease activity (p value < 0.05). In patients treated with FTY, those with the highest baseline 25(OH)D levels had a significantly lower number of active lesions at baseline; the same effect, even if weaker, was observed also at 2-year follow-up when adjusting for baseline disease activity. Given Vitamin D supplementation safety profile, also if a causal effect has not yet been shown, most of MS patients could probably benefit from 25[OH]D levels above those currently considered to be sufficient.