High-dose vitamin D supplementation in multiple sclerosis – results from the randomized EVIDIMS (efficacy of vitamin D supplementation in multiple sclerosis) trial

BACKGROUND: Epidemiological, preclinical, and non-interventional studies link vitamin D (VD) serum levels and disease activity in multiple sclerosis (MS). It is unclear whether high-dose VD supplementation can be used as an intervention to reduce disease activity. OBJECTIVES: The study aimed to compare the effects of every other day high- (20,400 IU) versus low-dose (400 IU) cholecalciferol supplementation on clinical and imaging markers of disease activity in patients with relapsing–remitting MS or clinically isolated syndrome. METHODS: The EVIDIMS (efficacy of vitamin D supplementation in multiple sclerosis) trial was a multicentre randomized/stratified actively controlled explorative phase 2a pilot trial with a double-blind intervention period of 18 months, add on to interferon-β1b. RESULTS: Fifty-three patients were randomized, and 41 patients completed the study. Cholecalciferol supplementation was well tolerated and safe in both arms. After 18 months, clinical (relapse rates, disability progression) and radiographical (T2-weighted lesion development, contrast-enhancing lesion development, brain atrophy) did not differ between both treatment arms. Post-study power calculations suggested that the sample size was too low to prove the hypothesis. CONCLUSIONS: The results neither support nor disprove a therapeutic benefit of high-dose VD supplementation but provide a basis for sound sample size estimations in future confirmatory studies. www.clinicaltrials.gov/NCT01440062