CARLSBAD, CA -  Ionis Pharmaceuticals, Inc. announced  that the U.S. Food and Drug Administration (FDA) has granted zilganersen Fast Track designation for the treatment of children and adults with an ultra-rare, progressive and ultimately fatal neurological disorder known as Alexander disease (AxD). Topline data from the pivotal study of zilganersen is expected in the second half of 2025. The FDA grants investigational medicines Fast Track designation to facilitate the development and expedite the review of medicines that demonstrate the potential to treat serious conditions and fill an unmet medical need.

"With no approved treatments available for people living with AxD, receiving this Fast Track designation for zilganersen reflects the seriousness of this ultra-rare disease and the significant unmet need for treatment in this patient population," said Eugene Schneider, M.D., executive vice president and chief clinical development officer at Ionis. "Zilganersen was designed to address the underlying cause of disease and help improve the functioning of people living with AxD. We look forward to a data readout next year and working closely with the FDA to potentially bring forward the first approved AxD treatment."

The Phase 1-3 study of zilganersen in adults and children living with AxD completed enrollment earlier this year across 13 sites in eight countries