The FDA approved the first disease-modifying drug for Alexander disease

Nature Biotechnology reported on Oct. 12 that the FDA has approved Ionis Pharmaceuticals' Zanvastro (zilganersen), the first disease-modifying drug for Alexander disease, a rare and often fatal brain disorder. The agency's Sept. 3 decision covers pediatric and adult patients. Zanvastro is an antisense oligonucleotide that reduces excess glial fibrillary acidic protein. A clinician injects it into the spinal canal every three months.

The FDA described a randomized controlled trial of 49 patients ages 2 and older, plus a small open-label group under age 2. Among patients 5 and older who already had trouble walking, those who received the drug had a significantly better walking speed at 61 weeks than those who were not treated. Treated children ages 2 to 4 gained motor skills, including standing, walking, running, and jumping, while untreated children declined. For infants under 2, the agency had safety data from four patients and drug-level modeling, not a controlled comparison. Survival was not the result reported. The drug is not a cure. Common side effects include vomiting, back pain, cough, headache, and post-lumbar puncture syndrome, and aseptic meningitis has been reported.