Ionis Pharmaceuticals reports zilganersen study met primary, secondary endpoints

Ionis Pharmaceuticals (IONS) announced topline results from the pivotal study of zilganersen in children and adults living with Alexander disease, a rare, progressive and often fatal neurological condition with no approved disease-modifying treatments. Zilganersen 50 mg demonstrated statistically significant and clinically meaningful stabilization on the primary endpoint of gait speed as assessed by the 10-Meter Walk Test compared to control at week 61 with favorable safety and tolerability. Zilganersen also demonstrated consistent benefit in key secondary endpoints. These data mark the first time an investigational medicine has shown a positive disease-modifying impact in AxD. In addition to achieving the primary endpoint, zilganersen demonstrated consistent favorable trends across key secondary endpoints, indicating evidence of slowed disease progression, stabilization or improvement. Key secondary endpoints include change from baseline in patients’ self-identified Most Bothersome Symptom Score, Patient Global Impression of Severity Score, Patient Global Impression of Change Score and Clinician Global Impression of Change Score. Zilganersen demonstrated a favorable safety and tolerability profile, with most adverse events being mild or moderate in severity. Incidence of serious adverse events was numerically lower in the zilganersen arm as compared to the control arm. Ionis plans to submit a new drug application to the FDA in Q1 2026 and is evaluating the potential to initiate an Expanded Access Program in the U.S. Detailed data will be presented at an upcoming medical conference.