First patient dosed in pivotal Phase 3 REVEAL clinical study of ION582 in Angelman syndrome
June 11, 2025 PDF Version - Completion of enrollment anticipated in 2026 -
CARLSBAD, Calif.--(BUSINESS WIRE)--Jun. 11, 2025-- Ionis Pharmaceuticals, Inc. (Nasdaq: IONS) today announced that the first participant has been dosed in the global Phase 3 REVEAL study, which is designed to evaluate the efficacy and safety of ION582, an investigational medicine for the treatment of people living with Angelman syndrome (AS), a serious and rare neurodevelopmental disorder that leads to significant physical and cognitive impairments.
“Dosing the first person with Angelman syndrome in our pivotal REVEAL study marks an important milestone for this underserved community, who currently have no approved disease modifying treatments,” said Holly Kordasiewicz, Ph.D., senior vice president of neurology, Ionis. “This placebo-controlled study will evaluate ION582 in both children and adults with either UBE3A deletion or mutation and builds on earlier encouraging findings from our Phase 1/2 HALOS study. This milestone reflects our commitment to those impacted by Angelman syndrome and builds on our legacy of innovation in neurology including the development of SPINRAZA and QALSODY. With ION582, we continue to advance our leading wholly owned neurology pipeline, which includes eight medicines in clinical development across a range of rare and more prevalent diseases.”
REVEAL (NCT06914609) is a global, randomized, double-blind, placebo-controlled Phase 3 study that will enroll approximately 200 children and adults with AS that have a maternal UBE3A gene deletion or mutation. During the 52-week treatment period, participants will be randomized 2:1 to receive either ION582 or placebo. Participants in the active treatment groups will receive quarterly 40 mg or 80 mg doses of ION582. Following the treatment period, eligible participants will transition into the long-term extension portion of the study where all participants will receive ION582 for up to 2 years. The primary endpoint is improvement in expressive communication as assessed by the Bayley Scales for Infant and Toddler Development-4 (Bayley-4), an objective and direct clinician-administered assessment of clinical functioning. Deficits in expressive communication are reported to be the symptoms most challenging to caregivers of people with AS. Secondary endpoints include overall disease severity, cognition, communication, sleep, motor functioning and daily living skills, in addition to other exploratory endpoints.
In the completed multiple ascending dose (MAD) portion of the Phase 1/2 open-label HALOS study, ION582 provided consistent and encouraging clinical improvement on all functional domains including communication, cognition and motor function and showed favorable safety and tolerability at all dose levels in the study.
For more information on the REVEAL clinical study, please visit www.ionisrevealstudy.com and www.clinicaltrials.gov. About ION582
ION582 is an investigational RNA-targeted antisense medicine designed to inhibit the expression of the UBE3A antisense transcript (UBE3A-ATS) and increase production of UBE3A protein, for the potential treatment of Angelman syndrome (AS). The U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) granted Orphan Drug designation to ION582. Additionally, the FDA granted Fast Track and Rare Pediatric designations to ION582.
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