Treatment May Delay Earliest MS Events

BOSTON -- Treatment with teriflunomide (Aubagio), a drug approved for relapsing multiple sclerosis (MS), reduced the risk of a clinical event in people with radiologically isolated syndrome (RIS), the phase III TERIS trial showed.

Compared with placebo, teriflunomide resulted in a 63% reduction in risk of a first clinical demyelinating event over 96 weeks in people with RIS (unadjusted HR 0.37, 95% CI 0.16-0.84, P=0.018), reported Christine Lebrun-Frenay, MD, of the University Hospital of Nice in France, in a presentation at the 2023 American Academy of Neurology annual meeting. Adjusted risk reduction was 72%.

"Our findings suggest that early intervention with teriflunomide may be beneficial to those diagnosed with radiologically isolated syndrome, the presymptomatic phase of MS," Lebrun-Frenay said.

"However, more research is needed in larger groups of people to confirm our findings," she continued. "It is important that medical professionals are cautious when using MRI expertise to diagnose this condition, selecting only patients at risk of developing MS and not increasing MRI misdiagnoses."

People with RIS have MRI features typical for MS without clinical symptoms that suggest central nervous system (CNS) demyelination. Early treatment may prevent the onset of a first clinical event and reduce the risk of new lesion development on MRI, decreasing the risk of permanent neurological impairment, Lebrun-Frenay noted.

Previously, the ARISE trial showed that dimethyl fumarate (Tecfidera) led to an 82% risk reduction (unadjusted) in developing MS relative to placebo in RIS.

"We were awaiting the TERIS study, the second of three randomized trials looking at whether treatment of RIS diminishes risk of clinical events consistent with MS," said John Corboy, MD, of the University of Colorado School of Medicine and Rocky Mountain MS Center at Anschutz Medical Campus, who wasn't involved with the study.

The first trial investigated dimethyl fumarate and the third is the ongoing CELLO study with ocrelizumab (Ocrevus), Corboy noted.

"Overall, the data are consistent with the original phase III trials with teriflunomide in relapsing remitting MS and similar to that seen with dimethyl fumarate in RIS, and again highlight that treatment at the earliest possible time after seeing signs of CNS demyelination has a positive impact in reducing clinical signs of MS," he said.

"It also, again, begs the question of what we call or how we define MS, as RIS presently remains outside the formal criteria for MS, which still requires at least one typical MS clinical event," Corboy observed. "We still do not know the actual number of people with truly asymptomatic RIS."

Studies looking at other markers, especially in high-risk patients like asymptomatic first-degree relatives of those with MS, are underway, he added. "These studies may help define the true denominator of those with RIS," he said.

TERIS randomized 89 participants in France, Switzerland, and Turkey who fulfilled 2009 RIS criteria 1:1 to teriflunomide 14 mg daily or placebo. The primary outcome was time to the first event from study entry. Assessments were performed at baseline and weeks 48 and 96.

Most participants (70.8%) were female and mean age of the group was 39. Index MRI motives included headache (47%), follow-up for other neurological diseases (18%), dizziness or vertigo (13.5%), and ophthalmology (7%).

Overall, 28 clinical events were detected during follow-up, 20 in the placebo group and eight in the teriflunomide group.

Compared with placebo, the number of patients with gadolinium-enhancing lesions and the cumulative number of new or enlarging T2 lesions were reduced in the teriflunomide arm, but between-group MRI differences were not statistically significant.

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