07:41 AM EDT, 09/09/2025 (MT Newswires) -- Ionis Pharmaceuticals ( IONS ) said Tuesday that the US Food and Drug Administration has granted Breakthrough Therapy designation to ION582 to treat patients with Angelman syndrome, a rare neurological disease.

The company said the designation is based on a phase 1/2 study of ION582 that showed "consistent and encouraging clinical improvement."

Ionis said enrollment in the pivotal late-stage study of ION582 is on track to complete next year.