Ionis Pharmaceuticals, Inc. (NASDAQ:IONS) released topline results on Monday from the pivotal study of zilganersen in children and adults living with Alexander disease (AxD), a rare, progressive, and often fatal neurological condition.
The neurological disorder destroys the myelin sheath protecting nerve fibers, caused by a mutation in the GFAP gene.
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 (10MWT) compared to control at week 61 (mean difference 33.3%, p=0.0412) with favorable safety and tolerability.
Zilganersen also demonstrated consistent benefit in key secondary endpoints.
The data mark the first time an investigational medicine has shown a positive disease-modifying impact in AxD.
Zilganersen also 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. The incidence of serious adverse events was numerically lower in the zilganersen arm than in the control arm.
Ionis plans to submit a new drug application to the U.S. Food and Drug Administration in the first quarter of 2026 and is evaluating the potential to initiate an Expanded Access Program in the U.S.
Price Action: IONS stock is up 4.88% at $63.99 during the premarket session at the last check on Monday.
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