SAN DIEGO, U.S, Aug 28, 2026
Acadia Pharmaceuticals Inc. announced that the European Commission (EC) 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 approval makes DAYBU the first and only treatment approved for Rett syndrome in the European Union, addressing a significant unmet medical need in the rare neurodevelopmental disorder.
DAYBU Approval Expands Rett Syndrome Treatment
The European authorization is primarily supported by results from the Phase 3 LAVENDER™ study, which demonstrated statistically significant and clinically meaningful improvements in core features of Rett syndrome. The study evaluated outcomes using the Rett Syndrome Behaviour Questionnaire (RSBQ) and Clinical Global Impression-Improvement (CGI-I) scales as co-primary endpoints. These findings supported the regulatory assessment of trofinetide as a new therapeutic option for patients whose disease has historically had very limited treatment choices. Following the EC decision, DAYBU is authorized for marketing across all 27 European Union member states, as well as Iceland, Liechtenstein and Norway. Acadia said it will next begin pricing and reimbursement discussions with relevant national authorities, an important step toward determining availability for patients across European healthcare systems.
Trofinetide Targets Neurobehavioral Symptoms
Rett syndrome is a rare and complex neurodevelopmental disorder, occurring in approximately one in every 10,000 to 15,000 female births worldwide. The condition is typically associated with mutations in the MECP2 gene and can involve developmental regression, loss of communication abilities, impaired purposeful hand use, motor deterioration and characteristic hand stereotypies. Many individuals living with Rett syndrome require intensive, lifelong care, creating a substantial burden for patients, families and caregivers. DAYBU contains trofinetide, an active substance derived from a molecule associated with insulin-like growth factor 1 (IGF-1). In Rett syndrome, IGF-1 levels in the brain are thought to be lower than normal, potentially affecting nervous-system function. Trofinetide was developed to address mechanisms associated with these neurological abnormalities and is already approved under the name DAYBUE® in the United States and Canada.
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European Launch Marks Rare Disease Milestone
The European approval represents a significant development for rare disease therapeutics, particularly because no approved treatment options for Rett syndrome had previously been available in the EU. Acadia said the authorization will allow the company to begin efforts to support patient and healthcare-provider access while national pricing and reimbursement processes progress. The European approval represents a significant development for rare disease therapeutics, particularly because no approved treatment options for Rett syndrome had previously been available in the EU. Acadia said the authorization will allow the company to begin efforts to support patient and healthcare-provider access while national pricing and reimbursement processes progress. For the Rett syndrome community, the EU approval of DAYBU provides a new treatment option for adults and children aged five years and older and represents an important step in addressing the long-standing therapeutic gap in this rare neurological disease.
Source: Acadia Pharmaceuticals press release
