Otsuka Pharmaceutical and Ionis Pharmaceuticals announced positive Phase 3 results in the Fusion study for ulefnersen in FUS-associated amyotrophic lateral sclerosis. The data included statistically significant improvements in function and survival versus placebo, a key signal in a rare ALS subtype with no approved targeted therapy. The program aims to support expedited regulatory discussions, with the trial’s primary endpoint based on a joint-rank analysis measuring time to death or permanent ventilation, time to rescue, and change from baseline on the ALS Functional Rating Scale-Revised at day 505. The move adds to the expanding antisense oligonucleotide pipeline in neurodegeneration and strengthens the case for earlier, genotype-driven treatment in FUS-ALS.