Otsuka and Ionis reported positive phase 3 results from the Fusion study of ulefnersen in FUS-associated ALS, a rare genetic subtype with no approved targeted therapy. The companies said the data showed statistically significant improvement in function and survival measures versus placebo. The findings are being framed as a step toward potential expedited regulatory discussions, highlighting antisense approaches as a precision option for genetically defined neurodegeneration. Trial endpoints included time to death or permanent ventilation, time to rescue, and functional rating scale changes. For the ALS field, the result adds pressure on competitors to demonstrate similarly definitive efficacy in molecularly matched patient populations.