Ionis announces positive topline results from Phase 1/2a trial of ION582 for Angelman syndrome

Core Insights - Ionis Pharmaceuticals announced positive topline data from the HALOS Phase 1/2a study of ION582 for Angelman syndrome, showing safety, tolerability, and significant functional improvements in cognition, communication, and motor function [1][2][5] Company Developments - Ionis will independently advance ION582 and plans to discuss the Phase 1/2a results with regulatory authorities to design a pivotal program [2][4] - Biogen has chosen not to exercise its option to license ION582, allowing Ionis to retain full control over the drug's development [2] Clinical Study Details - The HALOS trial included a three-month multiple-ascending dose study with 51 patients aged 2-50, followed by a long-term extension evaluating higher doses for an additional 12 months [4][8] - Topline results indicated that approximately 65% of patients showed cognitive improvements on the Bayley-4 assessment at six months, with similar improvements in communication and motor skills [6][14] Safety and Efficacy - ION582 was found to be safe and well tolerated across all dose levels, with adverse events consistent with patient medical histories [6][8] - The study demonstrated consistent improvements across various measures, including the Bayley-4 and SAS-CGI-C scales, correlating with positive changes in EEG activity [6][14] Future Plans - Detailed results from the HALOS study are expected to be presented at the upcoming Angelman Syndrome Foundation meeting in July [8] - Ionis is committed to advancing ION582 into a pivotal study, aiming to address the significant unmet need for therapies in Angelman syndrome [4][8]