Superimposed relapses were associated with a significantly reduced risk of disability progression in a longitudinal, prospective cohort study of 1,419 multiple sclerosis patients (MS) of the progressive-onset type.
To determine the role of inflammatory relapses on disability in the progressive-relapsing phenotype of progressive-onset MS, the researchers collected data from, an international, observational cohort of MS patients, from January 1995 to February 2017. The study population included 1,419 adults with MS (553 in the relapse subgroup, 866 in a nonrelapse subgroup) from 83 centers in 28 countries; the median prospective follow-up period was 5 years. The patients included in the analysis had adult-onset disease, at least three clinic visits with Expanded Disability Status Scale (EDSS) score recorded, and a time frame of more than 3 months between the second and last visit.
Overall, patients with relapses had significantly less risk of disability progression after adjusting for confounding variables (adjusted hazard ratio, 0.83; 95% confidence interval, 0.74-0.94; P = .003). Disease progression was defined as worsening of the EDSS score.
In addition, the researchers examined the data in a stratified model and found a 4% relative decrease in the hazard of confirmed disability progression events for each 10% increment of follow-up time for receiving disease-modifying therapy (DMT). However, DMT did not reduce disease progression risk in progressive-onset MS patients without relapse.
“This suggests that relapses in progressive-onset MS, as a clinical correlate of episodic inflammatory activity, represent a positive prognostic marker and provide an opportunity to improve disease outcomes through prevention of relapse-related disability accrual,” the researchers wrote.
Interferon-beta was the most common DMT, given to 73% of the relapse patients and 56% of the nonrelapse patients, followed by glatiramer acetate (20% and 13%, respectively), and fingolimod (12% and 16%, respectively).
The study’s main limitation was the use of the EDSS as a measure of disability, as well as the absence of quantifiable disability change to confirm relapse, the researchers noted. However, “these findings provide further evidence for a progressive-onset MS phenotype with acute episodic inflammatory changes, thereby identifying patients who may respond to existing immunotherapies.”
The study was supported by grants from the National Health and Medical Research Council of Australia and the MSBase Foundation, a nonprofit organization that itself receives support from multiple companies, including Merck, Novartis, and Sanofi. Dr. Hughes had no financial conflicts to disclose, but most coauthors disclosed relationships with multiple companies including Merck, Novartis, Sanofi. Genzyme, and Biogen.
SOURCE: Hughes J et al. JAMA Neurol. 2018 Aug 6. doi: 10.1001/jamaneurol.2018.2109.