Disease-modifying therapies give patients with relapsing-remitting multiple sclerosis a lower risk of developing secondary progressive disease that may only be topped in specific patients with highly active disease by the use of nonmyeloablative hematopoietic stem cell transplantation, according to findings from two studies published online Jan. 15 in JAMA.
Thefound that interferon-beta, glatiramer acetate ( ), fingolimod ( ), natalizumab ( ), and alemtuzumab ( ) are associated with a lower risk of conversion to secondary progressive MS, compared with no treatment. Initial treatment with the newer therapies provided a greater risk reduction, compared with initial treatment with interferon-beta or glatiramer acetate.
DMTs reduced risk of conversion to secondary progressive MS
Few previous studies have examined the association between DMTs and the risk of conversion from relapsing-remitting MS to secondary progressive MS. Those that have analyzed this association have not used a validated definition of secondary progressive MS. J. William L. Brown, MD, of the University of Cambridge, England, and his colleagues used a validated definition of secondary progressive MS that was published in 2016 to investigate how DMTs affect the rate of conversion, compared with no treatment. The researchers also compared the risk reduction provided by fingolimod, alemtuzumab, or natalizumab with that provided by interferon-beta or glatiramer acetate.
Dr. Brown and his colleagues analyzed prospectively collected clinical data from an international observational cohort study called. Eligible participants had relapsing-remitting MS, the complete MSBase minimum data set, at least one Expanded Disability Status Scale ( ) score recorded within 6 months before baseline, and at least two EDSS scores recorded after baseline. Participants initiated a DMT or began clinical monitoring during 1988-2012. The population had a minimum follow-up duration of 4 years. Patients who stopped their initial therapy within 6 months and those participating in clinical trials were excluded.
The primary outcome was conversion to secondary progressive MS. Dr. Brown and his colleagues defined this outcome as an EDSS increase of 1 point for participants with a baseline EDSS score of 5.5 or less and as an increase of 0.5 points for participants with a baseline EDSS score higher than 5.5. This increase had to occur in the absence of relapses and be confirmed at a subsequent visit 3 or fewer months later. In addition, the increased EDSS score had to be 4 or more.
After excluding ineligible participants, the investigators matched 1,555 patients from 68 centers in 21 countries. Each therapy analyzed was associated with reduced risk of converting to secondary progressive MS, compared with no treatment. The hazard ratios for conversion were 0.71 for interferon-beta or glatiramer acetate, 0.37 for fingolimod, 0.61 for natalizumab, and 0.52 for alemtuzumab, compared with no treatment.
Treatment with interferon-beta or glatiramer acetate within 5 years of disease onset was associated with a reduced risk of conversion (HR, 0.77), compared with treatment later than 5 years after disease onset. Similarly, patients who escalated treatment from interferon-beta or glatiramer acetate to any of the other three DMTs within 5 years of disease onset had a significantly lower risk of conversion (HR, 0.76) than did those who escalated later. Furthermore, initial treatment with fingolimod, alemtuzumab, or natalizumab was associated with a significantly reduced risk of conversion (HR, 0.66), compared with initial treatment with interferon-beta or glatiramer acetate.
One of the study’s limitations is its observational design, which precludes the determination of causality, Dr. Brown and his colleagues said. In addition, functional score subcomponents of the EDSS were unavailable, which prevented the researchers from using the definition of secondary progressive MS with the best combination of sensitivity, specificity, and accuracy. Some analyses were limited by small numbers of patients, and the study did not evaluate the risks associated with DMTs. Nevertheless, “these findings, considered along with these therapies’ risks, may help inform decisions about DMT selection,” the authors concluded.
Financial support for this study was provided by the National Health and Medical Research Council of Australia and the University of Melbourne. Dr. Brown received a Next Generation Fellowship funded by the Grand Charity of the Freemasons and an MSBase 2017 Fellowship. Alemtuzumab studies conducted in Cambridge were supported by the National Institute for Health Research Cambridge Biomedical Research Centre and the MS Society UK.