Older patients with secondary progressive multiple sclerosis (SPMS) have reduced risk of experiencing disease relapse, according to a study presented at the 7th Joint ECTRIMS-ACTRIMS Meeting, being held Oct. 25-28, in Paris, France.
The study, “Relapses in patients with secondary progressive MS: a matter of disease duration or age?” was presented by K. Ahrweiller, from the department of neurology at Rennes University Hospital, France.
Much has been learned about MS and the different forms the disease can present. However, little is known about the secondary progressive phase of MS.
A better understanding about SPMS and the molecular mechanisms it involves can help develop and explore disease-modifying treatments for this specific population of patients.
For this study, researchers characterized relapse rates and analyzed potential predictive factors for relapses, such as age, disease duration, sex, and disability scores, in a group of 506 patients with diagnosed SPMS.
Patients were followed at Rennes University Hospital for a mean time period of about 14.3 years since SPMS onset, and 35 percent of them had experienced at least one relapse during the SPMS phase.
The team found that the probability of having at least one relapse following SPMS onset was 24 percent at 5 years, and 34 percent at 10 years.
The risk of relapse during SPMS was found to decrease with disease duration and age.
Calculation of annualized relapse rates (ARR) showed that patients aged 30-40 years had 0.11 ARR, whereas patients 40-50 years old had an ARR of 0.06. Patients aged 50-60 had an ARR of 0.04, and patients older than 60 years presented an ARR of 0.01.
This result was further confirmed by calculating ARR again, but excluding data from disease-modifying treatments.
“The risk of relapses in SPMS mainly decreased with age,” Ahrweiller said, adding that there is a “possible impact of relapses on short-term disability worsening for the first 5 years,” but “no impact of relapses on disability worsening beyond the first 5 years” of SPMS onset.
Ahrweiller and his team believe the use of therapies aiming to reduce inflammation would be suitable for the treatment of younger SPMS patients because they have a higher risk of experiencing disease relapses.
“Treatments acting on focal inflammation may have a window of therapeutic opportunity, essentially in younger patients with SPMS during the first 5 years” he said.
Ahrweiller also emphasized that “older patients [more than] (55 years) without recent relapse should be included in clinical trials assessing potential effect of new drugs on disability worsening in SPMS. ”