High-dose N -acetyl cysteine reduces GFAP levels: Exploratory results from a pilot double-blind, placebo-controlled randomized trial

To assess whether oxidative stress drives biomarkers implicated in disability progression independent of relapses, we randomized 2:1 fifteen adults with progressive MS (Expanded Disability Status Scale (EDSS): 2.0–6.5) to receive high-dose oral N -acetyl cysteine (NAC, 1250 mg TID), a major source of endogenous antioxidants, or placebo for 4 weeks (NCT02804594). Using the Olink proximity extension assay, we measured 20 serum biomarkers at baseline and 4 weeks on treatment. NAC resulted in decreased glial fibrillary acidic protein (median change: −10.1 pg/mL vs. 39.5 pg/mL, p = 0.008) alongside stable neurofilament light chain levels (median change: 0.25 pg/mL vs. 0.61 pg/mL, p = 0.777). Our exploratory biomarker findings suggest NAC may be a promising agent to delay MS progression.