EC greenlights Acadia’s DAYBU for Rett Syndrome in Europe

Acadia Pharmaceuticals has secured European Commission approval for DAYBU (trofinetide), opening the door to the first treatment authorised for the neurobehavioural symptoms of Rett syndrome in the European Union (EU).

The decision covers adults and children aged five and older across all 27 EU member states, as well as Iceland, Liechtenstein, and Norway.

Patients may still have a little while to wait to access the drug, as Arcadia will now have to negotiate pricing and reimbursement deals with individual countries before it can be distributed.

The EC’s decision was primarily based on results from Acadia’s Phase 3 LAVENDER study, a 12-week randomised, double-blind, placebo-controlled trial evaluating the efficacy and safety of DAYBU in patients with Rett syndrome five to 20 years of age. Findings from the study showed that patients treated with trofinetide improved in core Rett syndrome symptoms, as measured using the Rett Syndrome Behaviour Questionnaire (RSBQ) and the Clinical Global Impression-Improvement (CGI-I) scale.

Rett syndrome is a rare genetic neurological disorder that impacts brain development, often caused by mutations in the MECP2 gene. It affects approximately one in every 10,000-15,000 girls born worldwide each year. Children with the condition typically begin to present with symptoms between six and 18 months, when their developmental skills may appear to slow or stagnate, followed by a regression phase, during which they can lose communication skills and purposeful hand movements.

The disorder can have a lasting impact on movement, communication, and cognitive function, and many people with Rett syndrome require intensive, round-the-clock care as they grow older.

Trofinetide is derived from a fragment of insulin-like growth factor 1 (IGF-1), a hormone involved in the development and function of the nervous system. By decreasing inflammation in the brain, the drug helps to restore the normal synaptic communication and brain plasticity typically disrupted in Rett syndrome.

“The approval of DAYBU marks a significant milestone for the Rett syndrome community in the EU and advances our mission to bring this innovative treatment to patients and families who have long faced a profound unmet medical need,” said Catherine Owen Adams, Acadia’s CEO. “For people living with Rett syndrome, a devastating rare neurodevelopmental disorder, there have been no approved treatment options in the EU. We are proud to make DAYBU available and look forward to supporting patients, caregivers, and healthcare providers gain access to treatment."

The drug is already available in the US, where it is marketed as DAYBUE and was approved by the FDA in 2023 for adults and children aged two and older. It is also approved in Canada.

The EU approval therefore extends an established commercial product into a new major market, while giving Acadia a first-mover position in European Rett syndrome treatment.