This is the first and largest study that explored mortality associated with beta interferon for treatment of MS in the clinical setting.
Elaine Kingwell, PhD
According to the results of a recent study, those with multiple sclerosis who took beta interferon had a 32% lower mortality than those who did not take the drug, which was particularly evident among those who took beta interferon for more than 3 years.
The researchers investigated the association between beta interferon and mortality risk in an observational study of 5989 adult patients with relapsing multiple sclerosis initially registered at 1 of 4 multiple sclerosis clinics in Canada between 1980—2004, or France between 1976–2013.
“This is the first and largest study of its kind, and it shows that a common treatment for multiple sclerosis may prolong life,” lead author Elaine Kingwell, a research associate and epidemiologist in the Djavad Mowafaghian Centre for Brain Health and the faculty of medicine at UBC, and Vancouver Coastal Health Research Institute, told NeurologyLive. “We found that people with MS who had taken beta interferon survived longer overall than people with MS who did not take these drugs. There was a significant 32% lower mortality risk for those who had taken beta interferon. Moreover, this was a consistent finding—there was a lower risk in both women and men who had taken beta interferon, and among two separate groups of people with MS in Canada and in France.”
Data were assessed from the clinical multiple sclerosis databases and from individually linked health administrative data. Participants were followed from their first clinic visit, 18th birthday, or Jan. 1, 1996, until death, emigration, or Dec. 31, 2013. Researchers only included those in this analysis with relapsing-onset multiple sclerosis who were naïve to disease-modifying therapy and immunosuppressant treatment of multiple sclerosis.
Among the 5989 participants, 75% were female, with a mean age of 42 years at study entry, there were 742 deaths (70%) female, and the mean age at death was 61 years.
The primary outcome measure was death due to any cause, while the secondary outcome measure included multiple sclerosis-related death.
The benefits of beta-interferons were compared to those of other available therapies during the study which included glatiramer acetate, immunosuppressants like azathioprine or mitoxantrone, natalizumab, and fingolimod. During an average of 11 and up to 18 years of follow-up, 32% of participants were exposed to beta interferon for at least 6 months, 12% to glatiramer acetate for at least 6 months, and 13% to another disease-modifying therapy for at least 1 day.
“Although there are several disease disease-modifying therapies available for the treatment of MS now, the beta interferons were the first drugs to be licensed for MS back in the mid-1990s,” Kingwell explained. “This means they have been used to treat MS for longer than any other disease-modifying therapy, and long enough to allow us to look at a longp-term outcome such as survival. A large amount of people and a long duration of follow-up are necessary to study this type of long-term outcome; for this study we were able to follow nearly 6000 people for up to 28 years, in both Canada and France.”
Findings were consistent between the 2 geographic groups, between men and women, and when only multiple sclerosis-related deaths were considered. Patients who took beta interferon for at least 6 months reported a reduced mortality risk in comparison to those who did not take beta interferon.
Among the 742 deaths, 489 (66%) were multiple sclerosis-related with a mean age at death of 59 years. Similarly, to all-cause deaths, researchers found a survival advantage for beta interferon exposure, with a 29% lower risk of multiple sclerosis-related death among those treated compared to untreated patients. With all-cause deaths, the odds of beta interferon exposure were lower among multiple sclerosis-related death cases compared to matched controls (odds ratio: .71; 95% CI:.51—.98).
“The association between beta interferon and survival was stronger for people who took beta interferon for at least 3 years,” Kingwell added. “Interestingly, we found that even people who started taking beta interferon later in their disease course (5 or more years after the onset of their MS), or older than age 40 lived longer than people who did not take beta interferons.”
Kingwell explained that this approach to studying beta interferon can be used in the future to address how other MS therapies may impact survival. This study provides evidence for a significant survival advantage for patients with relapsing-onset multiple sclerosis who receive beta interferons during clinical practice.
Additional research is needed to assess the survival advantages for other disease-modifying therapies and if this observed survival advantage results in a measurable improvement in the quality of life for patients.
“Longevity is an important outcome; however, we should not overlook the importance of quality of life and its association with disease modifying drugs—this warrants more research,” Kingwell concluded.
Kingwell E, Leray E, Zhu F, et al. Multiple sclerosis: effect of beta interferon treatment on survival. BRAIN. 2019;0;1—10. doi: 10.1093/brain/awz055.