Acadia Pharmaceuticals (Nasdaq: ACAD) announced that the European Commission has granted marketing authorization for DAYBU (trofinetide) for the treatment of neurobehavioral symptoms of Rett syndrome in adults and pediatric patients aged five years and older.

The company claims the drug is the first treatment approved for Rett syndrome in the European Union. The authorization covers all 27 EU member states, as well as Iceland, Liechtenstein, and Norway.

The approval is based primarily on results from the Phase 3 LAVENDER study, which showed statistically significant improvements in core features of Rett syndrome as measured by the Rett Syndrome Behaviour Questionnaire and Clinical Global Impression-Improvement scale co-primary endpoints.

Rett syndrome is a rare neurodevelopmental disorder occurring in approximately one in every 10,000 to 15,000 female births worldwide. It is typically caused by a genetic mutation on the MECP2 gene and is associated with loss of communication skills, impaired hand use, and motor deterioration.

Acadia said it will begin pricing and reimbursement negotiations with national authorities as a next step toward making the treatment available to patients across the EU. Trofinetide is already approved in the United States and Canada under the name DAYBUE.