Are Disease-Modifying Therapies Beneficial in Secondary Progressive MS?
Information sourced from NEJM Journal Watch:
Disease Modifying Therapies Not Beneficial in Secondary Progressive Multiple Sclerosis
A retrospective repository analysis found no difference in disability worsening between treated and untreated patients.
To examine whether medications for multiple sclerosis (MS) alter disease progression in secondary progressive MS (SPMS), researchers assessed outcomes in MSBase, which includes more than 36,000 patients from 122 MS centers in 57 countries. SPMS was defined retrospectively by research criteria.
Out of 2381 patients receiving or not receiving treatment, propensity matching and censoring led to 689 in the treated group and 689 in the untreated group. Treatments used in more than 5% of the population included interferon (62%), glatiramer (17%), natalizumab (10%), and fingolimod (7%). Mean age was 48 years, disease duration 15 years, median ambulatory disability without assistance was 100 to 200 meters, and median follow-up was 2 years. The proportions of patients with new or enhancing lesions during follow-up were 20% in the treated group and 23% in the untreated group. The groups had no observed differences in confirmed disability worsening or in risk for becoming wheelchair bound. Those on high-efficacy therapies experienced a 30% decrease in relapses but no benefit regarding disability.
This study involved a large database and propensity matching and showed no treatment effect between treated and untreated patients with SPMS. This important study should prompt more debate and research about the benefit of long-term MS therapies. Several limitations are important to consider. Although propensity matching is a powerful tool, this was not a randomized study, and there may be unknown variables between patients who are treated versus those who discontinue treatment. Whereas some patients had follow-up for >4 years, median follow-up was 2 years — perhaps not enough time to appreciate any long-term benefits. Because treatments were largely standard-efficacy agents, this study was underpowered to show whether high-efficacy therapies provide additional benefit on disability. Randomized discontinuation studies are underway to determine the safety of stopping treatment. For patients who wish to discontinue due to older age or progressive MS, a program of withdrawal under medical and imaging observation would be prudent to identify disease reactivation, should it occur.
Robert T. Naismith, MD reviewing Lorscheider J et al. Neurology 2017 Sep 5.