Finding treatments for advanced multiple sclerosis has been difficult. But new research may help neurologists identify which drugs are best for people with secondary progressive MS. Most people with MS are initially diagnosed with relapsing-remitting MS. More than half of these people eventually transition to secondary progressive MS. A new study found that the more potent disease-modifying drugs are more effective in reducing flare-ups in secondary progressive MS than the less potent drugs that tend to be safer to take.

The study involved 1,000 people with secondary progressive MS. Participants were followed for 10 years to see whether they had relapses and if they became more disabled over time. The team, led by researchers at the Department of Medicine at the University of Melbourne, in Melbourne, Australia, divided participants into two groups: those treated with one of the more potent drugs, or high-efficacy drugs (natalizumab, alemtuzumab, mitoxantrone, ocrelizumab, rituximab, cladribine and fingolimod); and those treated with one of the less potent drugs, or low-efficacy drugs (beta interferon, glatiramer acetate and teriflunomide). People in each group were matched for factors such as disability level and how long they had secondary progressive MS.

After accounting for the lag time before a person starts to experience the benefit of a medication, researchers found that in people with active disease, or those experiencing relapses within the past two years, people who were treated with high-efficacy medications experienced 30 percent fewer relapses than people treated with low-efficacy medications. People in the high-efficacy group experienced an average of 0.17 relapses per year compared 0.27 relapses per year in the low-efficacy group.

A limitation of the study was that participants were grouped by those taking high-efficacy or low-efficacy therapies. However, therapies were not studied individually. The study’s authors said it is possible that individual therapies may have different effects on symptoms and disability and recommend that they be examined separately in future research.

The study was published in Neurology.