Ionis Pharmaceuticals’ investigational RNA-targeted therapy zilganersen has received Fast Track designation from the FDA for treating Alexander disease (AxD), an ultra-rare neurological disorder. This designation accelerates the development and review process for drugs addressing serious conditions with unmet medical needs. Zilganersen is the first investigational medicine in clinical development for AxD, which currently lacks any approved therapies. Ionis is also advancing other wholly owned pipeline candidates, including olezarsen for familial chylomicronemia syndrome and donidalorsen for hereditary angioedema, with potential for independent launches.