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.