Rett Syndrome Gets Its First EU Treatment. Thirty Pricing Negotiations Start Now.
- The European Commission granted marketing authorisation to Acadia Pharmaceuticals for DAYBU (trofinetide) on 24 August 2026, for neurobehavioral symptoms of Rett syndrome in adults and children aged five and older. It is the first and only treatment approved for Rett syndrome in the EU.
- The authorisation rests primarily on the Phase 3 LAVENDER study, which met co-primary endpoints on the Rett Syndrome Behaviour Questionnaire and the Clinical Global Impression-Improvement scale. The indication is neurobehavioral symptoms, not the underlying MECP2 disorder.
- Authorisation covers all 27 EU member states plus Iceland, Liechtenstein and Norway. Acadia states it will now begin pricing and reimbursement negotiations with national authorities, so nothing reaches patients until those conclude country by country.
- Rett syndrome affects roughly one in every 10,000 to 15,000 female births. Regression typically begins between six and 18 months, and most individuals live into adulthood requiring continuous care. Trofinetide is a molecule derived from IGF-1, levels of which are lower than normal in the Rett brain.
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First and only is accurate and it is not the same as available. The Commission has authorised one product across 30 jurisdictions, and Acadia now has to negotiate a price in each of them separately.
- Centralised authorisation, decentralised payment. One EC decision covers 27 member states plus 3 EEA countries. Every one of them prices independently, so the gap between approval and access is measured in national HTA cycles. Track first-launch countries, not the authorisation date.
- An orphan monopoly with no comparator cuts both ways. Being first and only removes reference pricing anchors, which helps at negotiation. It also means each of the 30 authorities prices a behavioural endpoint on the RSBQ and CGI-I scales with no precedent for what that is worth in this disease.
- The indication is symptomatic, and that shapes the value case. DAYBU treats neurobehavioral symptoms, not the MECP2 mutation driving the disorder. With patients living into adulthood on continuous care, the argument HTA bodies will test is caregiver burden over decades rather than disease modification.
Read the original source (Acadia Pharmaceuticals) →
CompaniesAcadia Pharmaceuticals
GeographyEuropean Union