Ionis secures FDA approval for Zanvastro, first disease-modifying therapy for rare Alexander disease

Ionis Pharmaceuticals announced that the U.S. Food and Drug Administration has approved Zanvastro, marking the first disease-modifying treatment for Alexander disease, a rare and often fatal neurological disorder.

The approval was based on a pivotal trial that measured walking speed as an indicator of motor function. Patients receiving Zanvastro maintained stable walking speed, while those on placebo experienced a 33% decline.

Early data also suggested that treatment of younger children might improve motor function rather than merely halt decline. Safety findings were favorable, with serious adverse events occurring more frequently in the control group.

The decision provides the first therapeutic option for both children and adults affected by Alexander disease and could open a pathway for further research into disease-modifying approaches for rare neurodegenerative conditions.