WEST PALM BEACH, FLORIDA — regardless of treatment assignment, according to new substudy data from the ASCLEPIOS I/II trials presented at the annual meeting held by the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS).
There are numerous studies supporting sNfL as a prognostic biomarker in MS, but a series of preplanned ASCLEPIOS substudies provided an opportunity to evaluate its predictive value across different therapies, according to Thomas P. Leist, MD, PhD, division chief, Multiple Sclerosis/Neuroimmunology, Thomas Jefferson University, Philadelphia, Pennsylvania.
These data “support the use of a single sNfL threshold to prognosticate disease activity in patients with relapsing-remitting MS on a disease-modifying therapy,” Dr. Leist reported.
When those with elevated sNfL levels, defined as being above the median (≥ 9.3 pg/mL), at 3 months were compared with those with lower sNfL levels (< 9.3 pg/mL), the on-treatment annualized rate of new or enlarging T2 lesions was 2.2-fold (P < .001) greater. When measured at 12 months, the annualized rate was 3.6-fold greater (P < .001).
These differences in annualized rates for higher sNfL levels at 3 months (3.67 vs 1.69) and 12 months (4.90 vs 1.37) were independent of assigned therapy.
The ASCLEPIOS I/II trials compared the injectable anti-CD20 monoclonal antibody ofatumumab to teriflunomide, an oral inhibitor of pyrimidine synthesis, using a double-dummy, double-blind protocol. In the two trials that were published together (N Engl J Med. 2020 Aug 6;383[6]:546-557. doi: 10.1056/NEJMoa1917246), the annualized relapse rate was about 50% lower for ofatumumab (P < .001 in both trials). Other markers of activity, such as new lesions on T1- and T2-weighted imaging as well as sNfL levels, all favored ofatumumab numerically even if not all the secondary measures reached statistical significance.
Is sNfL Relevant Independent of Treatment?
In this preplanned substudy, the question was whether sNfL levels over the course of early follow-up were prognostic regardless of treatment assignment. This was not only shown for the study population overall but for several important subpopulations, such as those defined by race and ethnicity and body mass index (BMI). Of the 1892 patients enrolled in the two ASCLEPIOS trials, baseline sNfL data collection, which was part of the study protocol, was available for 1746 (92.8%).
Nearly 90% of the patients enrolled in the ASCLEPIOS trials were White with the remainder nearly evenly split between Black, Asian, and other, a category that included unknown race. In all groups, the annualized mean rate of new or enlarging T2 lesions was more than double among those with a sNfL above the mean versus those below the mean.
While these results were based on an above-or-below mean sNfL threshold, “future work should evaluate how this single sNfL threshold could be optimized with a specific target and population in mind,” according to the lead investigator on this analysis, Silvia R. Delgado, MD, a professor in the Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida.
The BMI analysis also supported the same idea. Anne H. Cross, MD, Washington University School of Medicine, St. Louis, Missouri, who led this work, concluded that a single sNfL threshold was prognostic for all groups studied, “including those defined by BMI and age.”