Amyotrophic lateral sclerosis (ALS) is a progressive, fatal, neurodegenerative disease. Although the pathogenesis remains unresolved, oxidative stress is known to play a pivotal role. Edaravone works in the central nervous system as a potent scavenger of oxygen radicals. In ALS mouse models, edaravone suppresses motor functional decline and nitration of tyrosine residues in the cerebrospinal fluid. Areas covered: Three clinical trials, one phase II open-label trial, and two phase III placebo-control randomized trials were reviewed. In all trials, the primary outcome measure was the changes in scores on the revised ALS functional rating scale (ALSFRS-R) to evaluate motor function of patients. Expert opinion: The phase II open label trial suggested that edaravone is safe and effective in ALS, markedly reducing 3-nitrotyrosine levels in the cerebrospinal fluid. One of the two randomized controlled trials showed beneficial effects in ALSFRS-R, although the differences were not significant. The last trial demonstrated that edaravone provided significant efficacy in ALSFRS-R scores over 24 weeks where concomitant use of riluzole was permitted. Eligibility was restricted to patients with a relatively short disease duration and preserved vital capacity. Therefore, combination therapy with edaravone and riluzole should be considered earlier.

Sawada H. Clinical efficacy of edaravone for the treatment of amyotrophic lateral sclerosis. Expert Opin Pharmacother. 2017 May;18(7):735-738. doi: 10.1080/14656566.2017.1319937. PMID: 28406335.