The European Commission has granted San Diego-based Acadia Pharmaceuticals (Nasdaq: ACAD) marketing authorization for Daybu (trofinetide) as a treatment for the rare genetic neurodevelopmental disorder Rett syndrome. Daybu becomes the first drug approved for Rett syndrome in the EU. The authorization covers neurobehavioral symptoms in adults and pediatric patients aged five years and older, and extends across all 27 EU member states plus Iceland, Liechtenstein, and Norway.
The European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) initially issued a negative opinion, which Acadia challenged through a formal re-examination request. The CHMP subsequently reversed its position and issued a positive recommendation, leading to the EC's authorization. Acadia said it will now begin pricing and reimbursement negotiations with national authorities.
The EC authorization rests primarily on the Phase III LAVENDER study in patients with Rett syndrome. The trial used co-primary endpoints of the Rett Syndrome Behaviour Questionnaire (RSBQ) and the Clinical Global Impression-Improvement (CGI-I) scale. Acadia reported statistically significant and clinically meaningful improvements on both measures. The drug had previously received US FDA approval in 2023 under the brand name Daybue.