Since the identification, in 1993, of the causative gene for familial amyotrophic lateral sclerosis (ALS), which is associated with SOD1 mutations, research has focused on the pathogenesis and therapeutics of ALS for more than 30 years. Tofersen, a highly anticipated gene-specific therapy that has been aligned with the disease-specific pathology, has been approved for marketing by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) However, as significant data on tofersen's safety and efficacy are required, the evaluation of this treatment is ongoing. This paper introduces the current clinical and commercial status of Tofersen, along with expectations for its approval in Japan.