Ionis Pharma reports positive results from HALOS study of ION582 in people with Angelman syndrome

Ionis Pharmaceuticals, Inc. reported positive results from the completed multiple ascending dose (MAD) phase 1/2 open-label study of ION582 in Angelman syndrome (AS) patients. The study showed significant clinical improvement across communication, cognition, and motor function. Specifically, 97% of participants in medium and high dose groups exhibited improvement in AS symptoms, as measured by the Symptoms of Angelman Syndrome–Clinician Global Impression-Change (SAS-CGI-C). ION582 demonstrated favorable safety and tolerability at all dose levels.

AS is a rare neurodevelopmental disorder caused by loss of function in the maternal UBE3A gene, affecting 1 in 21,000 people globally. ION582, an investigational antisense medicine, aims to activate the paternal UBE3A gene to boost UBE3A protein production in the brain.

The HALOS trial, involving 51 participants aged 2-50, showed consistent benefits across all ages and genotypes. Improvements were noted in communication, cognition, and motor function. Ionis plans to discuss phase 3 study design with regulators later this year, aiming to start the pivotal study in early 2025.