Blood Neurofilament Light in Progressive Multiple Sclerosis
David Leppert, Harald Kropshofer, Dieter A. Häring, Frank Dahlke, Ashwini Patil, Rolf Meinert, Davorka Tomic, Ludwig Kappos, Jens Kühle
Abstract
BACKGROUND AND OBJECTIVES: To investigate the potential of plasma neurofilament light (pNfL) as a biomarker of disease progression and treatment response in progressive multiple sclerosis (PMS) with and without acute disease activity. METHODS: A post hoc blinded analysis of pNfL levels in 2 placebo-controlled, phase 3 studies in secondary progressive multiple sclerosis (SPMS; EXPAND) and primary progressive multiple sclerosis (PPMS; INFORMS) using siponimod and fingolimod, respectively, as active compounds was performed. pNfL levels were quantified using a single molecule array (Homebrew Simoa) immunoassay from stored ethylenediaminetetraacetic acid (EDTA) plasma samples of all patients who consented for exploratory biomarker analysis in either study; pNfL levels were divided into high (≥30 pg/mL) and low (<30 pg/mL) at baseline. We investigated the association of pNfL levels with disability progression, cognitive decline, and brain atrophy and their sensitivity to indicate treatment response through clinical measures. RESULTS: < 0.05). Independent of treatment, high vs low baseline pNfL levels were associated with significantly higher risks of confirmed 3-month (SPMS [32%], hazard ratio [95% CI] 1.32 [1.09-1.61]; PPMS [49%], 1.49 [1.05-2.12]) and 6-month disability progression (SPMS [26%], 1.26 [1.01-1.57]; PPMS [48%], 1.48 [1.01-2.17]), earlier wheelchair dependence (SPMS [50%], 1.50 [0.96-2.34]; PPMS [197%], 2.97 [1.44-6.10]), cognitive decline (SPMS [41%], 1.41 [1.09-1.84]), and higher rates of brain atrophy (mean change at month 24: SPMS, -0.92; PPMS, -1.39). Baseline pNfL levels were associated with future disability progression and the degree of brain atrophy regardless of presence or absence of acute disease activity (gadolinium-enhancing lesions or recent occurrence of relapses before baseline). pNfL levels were lower in patients treated with siponimod or fingolimod vs placebo-treated patients and higher in those having experienced disability progression. DISCUSSION: pNfL was associated with future clinical and radiologic disability progression features at the group level. pNfL was reduced by treatment and may be a meaningful outcome measure in PMS studies. TRIAL REGISTRATION INFORMATION: EXPAND (ClinicalTrials.gov identifier: NCT01665144) and INFORMS (ClinicalTrials.gov identifier: NCT00731692).