Ionis Pharmaceuticals Surges 5.57% on FDA Breakthrough Designation as $270M Volume Ranks 379th

On Sept. 9, 2025, , , ranking 379th in market activity. The rally followed the U.S. Food and Drug Administration’s (FDA) designation for ION582, an investigational treatment for Angelman syndrome (AS), a rare with no approved disease-modifying therapies. The designation, based on Phase 1/2 HALOS trial results showing consistent clinical improvements in communication, cognition, and motor function, accelerates regulatory review and underscores the unmet medical need in AS. Ionis is now enrolling patients in its global Phase 3 REVEAL study, expected to conclude by 2026.

ION582, an , has already received Orphan Drug, , and Rare Pediatric designations from the FDA and EMA. The drug aims to increase levels, addressing the genetic root of AS. Ionis highlighted the potential of ION582 to deliver meaningful benefits for patients, with its neurology portfolio including marketed therapies like SPINRAZA and QALSODY. The Breakthrough Therapy status reinforces the company’s focus on and positions ION582 as a key asset in its pipeline.

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