High-Dose Vitamin D Linked to Lower Disease Activity in CIS

COPENHAGEN, Denmark — High-dose oral cholecalciferol (vitamin D₃) supplementation significantly reduces evidence of disease activity in patients with clinically isolated syndrome (CIS), results of a randomized, controlled trial suggest.

In addition, cholecalciferol had a favorable safety profile and was well tolerated.

“These data support high-dose vitamin D supplementation in early MS and make vitamin D the best candidate for add-on therapy evaluation in the therapeutic strategy for MS,” said study author Eric Thouvenot, MD, PhD, University Hospital of Nimes, Neurology Department, Nîmes, France.

The study was presented on September 19 at the 40th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) 2024.

Sub Head

Research shows vitamin D deficiency is a risk factor for multiple sclerosis (MS). However, results of previous research investigating vitamin D supplementation in MS, with different regimens and durations, have been contradictory.

The current double-blind study included 303 adults newly diagnosed with CIS (within 90 days) and a serum 25-hydroxy vitamin D concentration of less than 100 nmol/L at baseline. Participants had a median age of 34 years, and 70% were women.

About one third of participants had optic neuritis, two thirds had oligoclonal bands from cerebrospinal fluid analysis, and the median Expanded Disability Status Scale (EDSS) score was 1.0. Of the total, 89% fulfilled 2017 McDonald criteria for the diagnosis of relapsing-remitting MS (RRMS).

Participants were randomly assigned to receive high-dose (100,000 international units) oral cholecalciferol or placebo every 2 weeks for 24 months. Participants had a clinical visit at 3, 6, 12, 18, and 24 months, and brain and spinal cord MRI with and without gadolinium at 3, 12, and 24 months.

The primary outcome was occurrence of disease activity — relapse, new or enlarging T2 lesions, and presence of contrast-enhancing lesions.

Significant Difference

During follow-up, 60.3% in the vitamin group showed evidence of disease activity vs 74.1% in the placebo group (hazard ratio [HR], 0.66; 95% CI, 0.50-0.87; P = .004).

In addition, the median time to evidence of disease activity was 432 days in the vitamin D group vs 224 days in the placebo group (P = .003).

“As you can see, the difference is really, really significant,” said Thouvenot, referring to a Kaplan-Meier curve. He said he was somewhat surprised by the “very rapid” effect of vitamin D.

He noted that the 34% reduction in relative risk for disease activity is “similar to that of some published platform therapies for CIS patients.”

An analysis of the 247 patients who met 2017 McDonald criteria for RRMS at baseline showed the same results.

Secondary analyses showed no significant reduction in relapses and no significant differences for annual change in EDSS, quality of life, fatigue, anxiety, or depression.

Additional analyses showed the HR was unchanged after adjusting for known prognostic factors including age, sex, number of lesions (< 9 vs ≥ 9), EDSS score at baseline, and delay between CIS and treatment onset.

Results showed vitamin D3 supplementation was safe and well tolerated. Thouvenot noted that 95% of participants completed the trial, and none of the 33 severe adverse events in 30 patients suggested hypercalcemia or were related to the study drug.

These encouraging new data support further studies of high-dose vitamin D supplementation as an add-on therapy in early MS, said Thouvenot. He noted that animal models suggest vitamin D added to interferon beta has a synergistic effect on the immune system.

‘Fabulous’ Research

During a question-and-answer session, delegates praised the study, with some describing it as “fantastic” or “fabulous.”

Addressing a query about why this study succeeded in showing the benefits of vitamin D while numerous previous studies did not, Thouvenot said it may be due to the longer duration or a design that was better powered to show differences.

Asked if researchers examined vitamin D blood levels during the study, Thouvenot said these measures are “ongoing.”

Responding to a question of whether high-dose vitamin D could be a life-long treatment, he referred again to the “excellent” safety of the intervention. Not only is it well tolerated, but vitamin D benefits bones and the risk for hypercalcemia is low except perhaps for patients with tuberculosis or sarcoidosis, he said.

“When you exclude those patients, the safety is huge, so I don’t know why we should stop it once it’s started.”

This study was funded in part by the French Ministry of Health. Thouvenot reported no relevant disclosures.