[Current Therapies for Amyotrophic Lateral Sclerosis in Japan]

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by progressive muscle wasting and weakness. Riluzole was the sole drug available for treating ALS until 2015, when edaravone was approved as a new anti-ALS drug. Recent discoveries of the disease-causal genes and proteins, as well as the rapid advancement of induced pluripotent stem (iPS) cell manipulations, drug deliveries, and molecular modifications have provided diverse and promising drug candidates. In particular, antisense-oligonucleotide therapy appears to significantly prevent disease progression when introduced early. Moreover, the in vitro modeling of ALS using patients' own iPS cells enables effective screening of approved drugs. Drug repositioning is a robust short-cut to bedside use in patients with ALS, due to the availability of data for safety concerns. Currently, five investigator-initiated drug trials are underway in Japan. These include trials of hepatocyte growth factor, perampanel, ultra-high-dose methylcobalamin, ropinirole, and bosutinib. This is a review of new ALS drugs that are either currently available or in on-going trials. We additionally review the pathogenic pathways that these drugs target.