Therapeutic frontiers in ALS: iPSC-based drug discovery, cell therapy, and gene therapy—Advances through 2026

Three converging therapeutic paradigms—iPSC-based drug discovery, cell transplantation, and gene therapy—have substantially expanded the therapeutic pipeline for amyotrophic lateral sclerosis (ALS) between 2020 and 2026. The FDA's accelerated approval of tofersen (Qalsody) in April 2023 marked the first treatment targeting a genetic cause of ALS. iPSC-derived drug candidates, including ropinirole and bosutinib, have completed early-phase clinical trials led by Japanese institutions. Cell therapies targeting neuroinflammation through regulatory T cells are being actively explored as immunomodulatory strategies, although efficacy remains to be established in adequately powered trials. Next-generation gene-silencing approaches—including RNA interference (RNAi) therapeutics and AAV-delivered microRNA—entered first-in-human trials in 2024–2025. The identification of STMN2 as a downstream target of TDP-43 dysfunction has opened a potential TDP-43-downstream nucleic acid therapeutic avenue for sporadic ALS, which constitutes approximately 90% of all cases, with company-reported interim data suggesting target engagement in the ongoing Phase 1/2 ANQUR trial (QRL-201). This review synthesizes the latest evidence across all three therapeutic domains, with attention to the hierarchy of evidence, regulatory milestones, and the pioneering contributions of Japanese research groups.