A new study finds that early treatment intervention with teriflunomide may lower the risk of multiple sclerosis in individuals with radiologically isolated syndrome. The results suggest a benefit to early treatment in the MS disease spectrum.

Radiologically isolated syndrome represents the earliest detectable preclinical phase of MS, punctuated by MRI white matter anomalies within the central nervous system. An international team of researchers wanted to know if it was possible to prevent MS with a disease-modifying treatment in people with preclinical demyelinating disease.

From September 2017 to October 2022, a multicenter clinical trial investigated the effect of teriflunomide in delaying MS in 89 participants with RIS, with a three-year follow-up. The setting included referral centers in France, Switzerland, and Turkey. Participants older than 18 years meeting the 2009 RIS criteria were randomly assigned to oral teriflunomide, 14 mg daily, or placebo up to week 96 or, optionally, to week 144. Clinical, MRI, and patient-reported outcomes were collected at the beginning and yearly until week 96, with an optional third year in the allocated group if no symptoms occurred.

The time to the first clinical event was significantly extended in the teriflunomide group compared with placebo. Secondary imaging end point outcomes – including the comparison of the cumulative number of new or newly enlarging T2 lesions, new gadolinium-enhancing lesions, and the proportion of participants with new lesions – were not significant.

Treatment with teriflunomide resulted in an unadjusted risk reduction of 63 percent and an adjusted risk reduction of 72 percent, relative to placebo, in preventing a first clinical demyelinating event. 

The researchers caution that before considering any immune intervention, it is essential to highlight the risk of misdiagnosing individuals with nonspecific MRI anomalies as having RIS, underscoring the role of MS tertiary centers in accurately classifying and managing such individuals.

The study was published in JAMA Neurology.