Acadia Pharmaceuticals Faces Setback in EU Rett Syndrome Drug Approval

Company expects negative CHMP opinion on trofinetide, plans to request re-examination

Feb. 3, 2026 at 5:31am

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Acadia Pharmaceuticals announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has issued a negative trend vote on the company's Marketing Authorization Application (MAA) for trofinetide, a treatment for Rett syndrome. Despite the disappointing news, Acadia intends to request a re-examination of the CHMP's opinion upon its formal adoption.

Why it matters

Rett syndrome is a rare, complex neurodevelopmental disorder that primarily affects young girls, and there are limited treatment options available. Trofinetide's potential approval in the EU would have provided a new therapeutic option for patients and families affected by this debilitating condition.

The details

Acadia Pharmaceuticals said it was informed by the CHMP of the negative trend vote on its MAA for trofinetide following the company's recent oral explanation. Subject to the outcome of the CHMP vote in February, Acadia plans to request a re-examination of the opinion by the CHMP upon its formal adoption. The company believes the strong data that supported trofinetide's approval in the US, Canada, and Israel demonstrates the meaningful benefits the drug can deliver to Rett syndrome patients.

  • Acadia expects to receive the CHMP's formal opinion in February 2026.
  • The company plans to request a re-examination of the CHMP opinion within 15 calendar days of receiving it.

The players

Acadia Pharmaceuticals Inc.

An American biopharmaceutical company focused on developing and commercializing innovative medicines to address central nervous system disorders.

Committee for Medicinal Products for Human Use (CHMP)

The committee responsible for preparing the European Medicines Agency's opinions on questions concerning medicines for human use.

European Medicines Agency (EMA)

The European Union's regulatory agency for the evaluation, supervision, and monitoring of medicines.

Catherine Owen Adams

Chief Executive Officer of Acadia Pharmaceuticals.

Trofinetide

A synthetic analog of the N-terminal tripeptide of insulin-like growth factor developed by Acadia Pharmaceuticals for the treatment of Rett syndrome.

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What they’re saying

“While the negative trend vote is disappointing and not what we hoped for, we believe the strong data that supported the approval of trofinetide for the treatment of Rett syndrome in the United States, Canada, and Israel speak to the meaningful benefits that trofinetide can deliver.”

— Catherine Owen Adams, Chief Executive Officer (Acadia Pharmaceuticals)

What’s next

Acadia Pharmaceuticals plans to request a re-examination of the CHMP's formal opinion on trofinetide within 15 calendar days of receiving it. The CHMP then has up to 60 days to re-examine its opinion.

The takeaway

The CHMP's negative trend vote on trofinetide is a setback for Rett syndrome patients in the EU who were hoping for a new treatment option. However, Acadia's commitment to pursuing the re-examination process demonstrates their dedication to making this potentially beneficial drug available to the European market.