In a related editorial, the author comments that “Despite the positive outcome of this trial and recent approval of edaravone by the US Food and Drug Administration for treatment of ALS, there are limitations which could make it difficult for clinicians to prescribe the drug with an expectation of efficacy. First, the inclusion criteria were stringent, as the investigators sought to reflect the clinical characteristics of the apparent responders identified by a previous post-hoc analysis. Second, the study duration was short, comprising 24 weeks in total, preceded by a 12-week observation period. Third, while it is biologically plausible that sub-cohorts of patients might respond differentially to targeted therapies, how to select such patients remains a conundrum, as at present there are no reliable markers of pathobiology. And finally, although the side-effect profile does not suggest toxicity, the treatment regimen of intravenous infusions for 10–14 days each month is inconvenient and potentially costly, and the longer term efficacy of the drug and patient adherence to the intravenous treatment has not been established.”
Edaravone is a free radical scavenger that is believed to relieve the effects of oxidative stress, a likely factor in the onset and progression of ALS. There are currently no development plans for this drug in the EU.