SAN DIEGO, June 26, 2026

Acadia Pharmaceuticals announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has issued a positive opinion recommending the approval of DAYBU (trofinetide) for treating neurobehavioral symptoms of Rett syndrome in adults and children aged five years and older. If approved by the European Commission in the coming months, DAYBU would become the first therapy approved in the European Union specifically for neurobehavioral symptoms of Rett syndrome, addressing a major unmet medical need for patients and caregivers. The recommendation follows a successful re-examination process and represents a significant regulatory milestone for the company as it expands the medicine’s availability beyond the United States.

Phase 3 Data Supported CHMP Positive Opinion

The CHMP recommendation was primarily supported by results from the Phase 3 LAVENDER study, where DAYBU demonstrated statistically significant and clinically meaningful improvements in the core symptoms of Rett syndrome. The study achieved positive outcomes on both the Rett Syndrome Behaviour Questionnaire (RSBQ) and the Clinical Global Impression-Improvement (CGI-I) scale, indicating meaningful benefits in neurobehavioral function. These findings suggest that treatment with trofinetide can improve some of the most challenging aspects of the disease that affect communication, behavior, and overall quality of life for patients while reducing the burden on caregivers.

European Commission Decision Expected Soon

Following the CHMP positive opinion, the European Commission is expected to issue its final regulatory decision in the coming months. If approved, the marketing authorization will be valid across all 27 European Union member states, along with Iceland, Liechtenstein, and Norway. Rett syndrome is a rare neurodevelopmental disorder caused primarily by mutations in the MECP2 gene, affecting approximately one in every 10,000 to 15,000 female births worldwide. The disease leads to progressive loss of communication skills, motor function, and independence, with no currently approved therapy in Europe targeting its neurobehavioral symptoms. The anticipated approval of DAYBU could establish a new treatment option for patients across the region.

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Acadia Expands Global Rare Disease Portfolio

Acadia Pharmaceuticals continues to strengthen its leadership in neurological and rare diseases through ongoing global regulatory expansion. DAYBU (trofinetide) is a synthetic analog of the N-terminal tripeptide of insulin-like growth factor-1 (IGF-1) designed to improve synaptic function associated with Rett syndrome. Beyond its commercial products, the company is advancing a broader pipeline focused on Alzheimer’s disease psychosis, Lewy body dementia psychosis, and other underserved neurological disorders, reinforcing its long-term strategy to deliver innovative therapies for patients with significant unmet medical needs.

Source: Acadia Pharmaceuticals press release