Ionis Drug Wins FDA Approval as First Alexander Disease Treatment

The U.S. Food and Drug Administration has approved Zanvastro (zilganersen), manufactured by Ionis Pharmaceuticals Inc. (NASDAQ:IONS), for Alexander disease in adult and pediatric patients.

Zanvastro becomes the first and only disease-modifying therapy available for this ultra-rare, progressive, and frequently fatal neurological disorder. Prior to this regulatory authorization, clinical care for affected individuals remained strictly limited to symptom management.

First Approved Disease-Modifying Treatment For Alexander Disease

Alexander disease impacts roughly one in every one to three million people worldwide, causing progressive cognitive, motor, autonomic, and gastrointestinal dysfunction.

The disease stems from mutations in the GFAP gene, which trigger the overproduction and toxic accumulation of glial fibrillary acidic protein in astrocytes.

Over time, astrocyte impairment harms surrounding neurons and myelin. As an RNA-targeted medicine, Zanvastro addresses this underlying mechanism by decreasing GFAP protein production.

Healthcare providers administer Zanvastro in 50 mg doses every quarter via an intrathecal injection.

Ionis Trial Demonstrates Significant Motor Function Improvements

In patients aged five and older, quarterly 50 mg administration met the primary endpoint by showing statistically significant and clinically meaningful stabilization in gait speed compared to control groups at Week 61.

The regulatory approval stems from positive results in a pivotal clinical study involving people living with the disease.

Assessments using the 10-Meter Walk Test demonstrated a 33.3% least-squares mean difference (p=0.041).

For pediatric patients aged two to four, Zanvastro demonstrated motor function improvements measured through the Gross Motor Function Measure-88.

Clinician, caregiver, and patient-reported secondary and exploratory endpoints consistently favored Zanvastro.

Recordati Partnership Drives European And Japanese Expansion

In June 2026, Ionis executed a licensing agreement with Italian specialty pharmaceutical firm Recordati, granting Recordati exclusive rights to commercialize and develop zilganersen outside the U.S.

Ionis is actively collaborating with Recordati on regulatory filings in Europe and Japan, with planned submissions slated for 2027.

IONS Price Action: Ionis Pharmaceuticals shares were up 0.57% at $58.46 during premarket trading on Friday, according to Benzinga Pro data.

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