Neuren Pharmaceut Clears Key EU Hurdle on DAYBU With US$35M Payment Now in Sight
Neuren’s DAYBU® clears key EU hurdle with positive CHMP opinion
On 29 June 2026, Neuren Pharmaceuticals (ASX: NEU) welcomed an announcement by its partner Acadia Pharmaceuticals Inc. (Nasdaq: ACAD) that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion recommending EU marketing authorisation for DAYBU® (trofinetide), following a re-examination procedure.
The recommendation covers treatment of neurobehavioral symptoms of Rett syndrome in adults and pediatric patients aged five years and older. According to the announcement, if granted by the European Commission (EC), DAYBU® would become the first therapy approved for this indication in the EU.
The positive opinion resolves a regulatory journey that began with an initial CHMP negative vote in early 2025, when concerns centred on treatment effect magnitude and long-term assessment rather than any safety issues with trofinetide.
A positive CHMP opinion represents the critical step before EC approval, moving Neuren materially closer to potential EU revenue from one of its lead therapies.
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What approval would mean for Neuren’s revenue
Neuren has granted an exclusive worldwide licence to Acadia for the development and commercialisation of trofinetide. Under the licence agreement, Neuren is entitled to milestone payments and royalties.
The European economics are clearly defined, but the associated payments remain contingent on EC marketing authorisation and a subsequent commercial launch. Neither outcome is yet guaranteed.
| Payment type | Amount | Trigger |
|---|---|---|
| First sale payment | US$35 million | Payable following first commercial sale in the EU |
| Sales milestone payments | Up to US$170 million | On achievement of escalating annual net sales thresholds |
| Royalties | Tiered, mid-teens to low-20s % | Of net sales |
CEO Commentary
“I am so delighted for all stakeholders to see this positive outcome from the CHMP re-examination process recommending marketing authorisation for DAYBU® in the EU. With no approved treatment currently available in the EU, approval of DAYBU® would represent an important step forward for patients, caregivers and the wider Rett syndrome community profoundly impacted by this devastating condition,” said Jon Pilcher, Chief Executive Officer of Neuren.
Understanding Rett syndrome — and why this matters
Rett syndrome is a rare, complex neurodevelopmental disorder typically caused by a genetic mutation on the MECP2 gene. It primarily affects females and is associated with progressive loss of motor and communication abilities over time.
The condition generally follows a recognised pattern of progression:
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Apparently normal early development until six to 18 months of age
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A regression phase, marked by loss of acquired communication skills and purposeful hand use
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A plateau period, with possible mild recovery in cognitive interests but severely diminished body movement
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Long-term motor deterioration, often requiring intense round-the-clock care for the remainder of the patient’s life
The disorder occurs in approximately 1 in every 10,000 to 15,000 female births worldwide. With no approved treatment currently available in the EU, the indication represents a clear unmet clinical need and underpins the commercial opportunity DAYBU® is positioned to address.
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Next steps and the broader Neuren pipeline
Following the CHMP recommendation, the EC will now review the opinion and is expected to issue a final decision in the coming months. If DAYBU® is approved, the marketing authorisation would apply to all 27 EU member states, as well as Iceland, Liechtenstein and Norway.
The CHMP opinion adds to existing approvals across other jurisdictions. DAYBUE® (trofinetide) oral solution is already approved by the US Food and Drug Administration (FDA), Health Canada and the Ministry of Health in Israel, while DAYBUE STIX (trofinetide) powder is approved by the FDA for the treatment of Rett syndrome.
The DAYBUE STIX nationwide rollout in the United States, completed in April 2026 following FDA approval of the powder formulation in December 2025, has already expanded Neuren’s royalty base domestically as expert consensus formally positions trofinetide as the standard of care for Rett syndrome.
Beyond trofinetide, Neuren is advancing a second drug candidate, NNZ-2591, an orally administered therapy targeting the role of Insulin-like growth factor 1 (IGF-1) in the brain.
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In clinical development as an oral solution treatment for multiple neurodevelopmental disorders
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Positive results achieved in Phase 2 clinical trials in Phelan-McDermid syndrome, Pitt Hopkins syndrome and Angelman syndrome
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Granted orphan drug designation in the United States and the European Union, as well as Fast Track and Rare Pediatric Disease designations from the FDA
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A Phase 3, randomised, double-blind, placebo-controlled trial (“Koala”) underway in children aged 3 to 12 years with Phelan-McDermid syndrome, alongside a 52-week open-label extension study
Neuren is also developing NNZ-2591 for the treatment of hypoxic ischemic encephalopathy (HIE), a serious condition caused by brain injury before or shortly after birth.
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