A drug called teriflunomide may delay first symptoms for people whose magnetic resonance imaging (MRI) scans show signs of multiple sclerosis (MS) even though they do not yet have symptoms of the disease. The preliminary study, released April 19, 2023, will be presented at the American Academy of Neurology's 75th Annual Meeting, being held in person in Boston and live online from April 22-27, 2023.

Called radiologically isolated syndrome, the condition is diagnosed in people who do not have MS symptoms but who have abnormalities in the brain or spinal cord called lesions, similar to those seen in MS. MS is a disease in which the body's immune system attacks myelin, the fatty white substance that insulates and protects the nerves. Symptoms of MS may include fatigue, numbness, tingling or difficulty walking.

"With more and more people having brain scans for various reasons, such as headache or head trauma, more of these cases are being discovered, and many of these people go on to develop MS," said study author Christine Lebrun Frenay, MD, of the University Hospital of Nice in France and a Fellow of the American Academy of Neurology. "The sooner a person can be treated for MS, the greater the chances of delaying damage to the myelin, which decreases the risk of permanent neurologic impairment and debilitating symptoms."

The study involved 89 people with radiologically isolated syndrome. Half of the people were given 14 milligrams (mg) of teriflunomide daily and the other half were given a placebo. They were followed for up to two years.

During the study, eight people who took the drug developed MS symptoms, compared to 20 who took the placebo.

After adjusting for other factors that could affect the risk of developing symptoms, researchers found that people taking teriflunomide had a 72% lower risk of experiencing first symptoms than those taking the placebo.

"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. Additionally, 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."