Ionis Pharmaceuticals, Inc. IONS released topline results on Monday from the pivotal study of zilganersen in children and adults living with Alexander disease (AxD), a rare, progressive, and often fatal neurological condition.The neurological disorder destroys the myelin sheath protecting nerve fibers, caused by a mutation in the GFAP gene.Zilganersen 50 mg demonstrated statistically significant and clinically meaningful stabilization on the primary endpoint of gait speed as assessed by the 10-Meter Walk Te ...