ACAD Announces New Review Following CHMP’s Decision Against Rett Syndrome Medication in Europe

Acadia Pharmaceuticals Faces EU Setback for Rett Syndrome Drug

Acadia Pharmaceuticals (ACAD) has received a formal negative recommendation from the Committee for Medicinal Products for Human Use (CHMP), part of the European Medicines Agency (EMA), regarding the approval of trofinetide for treating Rett syndrome in patients aged two and above within the European Union.

This outcome was anticipated, as Acadia had previously been notified of an unfavorable trend in the CHMP's assessment of its marketing application for trofinetide earlier this year. After the official decision, Acadia thoroughly reviewed the CHMP's reasons for rejection and intends to seek a re-examination. This regulatory hurdle has postponed the possibility of trofinetide’s approval in Europe.

Although the pivotal LAVENDER clinical trial achieved its main and key secondary goals, the CHMP cited several concerns in its refusal. These included the perception that trofinetide’s benefits after 12 weeks, while present, were relatively modest; that not all core symptoms of Rett syndrome were addressed in the study; and that patient dropouts over time may have influenced long-term results. Acadia views this feedback as constructive as it prepares for the next steps in the regulatory process.

Understanding Rett Syndrome

Rett syndrome is a rare neurological disorder, affecting approximately one in every 10,000 to 15,000 girls worldwide. Children typically develop normally at first, but symptoms usually appear between six and eighteen months of age, followed by a loss of previously acquired abilities. While some stabilization can occur, most patients experience progressive motor difficulties as time goes on.

Trofinetide’s Status in the United States

In 2023, the FDA approved trofinetide as the first and only therapy for Rett syndrome in both adults and children aged two and older. The medication is sold under the brand name Daybue in the U.S. market.

Over the past six months, Acadia’s stock price has declined by 10.9%, in contrast to a 19.7% gain for the broader biomedical and genetics industry.

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Growth Prospects for Acadia’s Marketed Products

Despite recent regulatory challenges, Acadia is positioned for sustained growth, largely due to its flagship products, Nuplazid and Daybue, in the United States. The company projects combined net sales of roughly $1.7 billion by 2028, with Nuplazid contributing $1 billion and Daybue $700 million.

• Nuplazid is the only FDA-approved treatment for hallucinations and delusions linked to Parkinson’s disease psychosis in the U.S. It is protected by patents until 2038, safeguarding its market position. In 2025, Nuplazid generated $680.1 million in revenue, marking a 12% increase year-over-year, primarily due to higher sales volume.
• Daybue has seen promising adoption since its 2023 launch. In 2025, sales reached $391.4 million, also up 12% from the previous year, as more patients began using the treatment.

In late 2025, the FDA approved Daybue Stix (trofinetide) for oral solution—a dye- and preservative-free powder—for treating Rett syndrome in both adults and children aged two and older. This new formulation broadens the Daybue product line, which remains the only FDA-approved option for this condition.

Acadia plans a limited rollout of Daybue Stix in early 2026, with wider distribution expected in the following quarter. The company will continue to offer the original oral solution alongside the new powder, further strengthening its presence in the Rett syndrome treatment landscape.

ACADIA Pharmaceuticals: Price Trends and Analyst Consensus

For more details, view the ACADIA Pharmaceuticals Inc. price-consensus chart or check the latest quote.

Analyst Ratings and Noteworthy Biotech Stocks

Acadia currently holds a Zacks Rank #3 (Hold).

Other highly rated biotech stocks include:

• USANA Health Sciences (USNA)
• Catalyst Pharmaceuticals (CPRX)
• ALX Oncology Holdings (ALXO)

USNA and CPRX both have a Zacks Rank #1 (Strong Buy), while ALXO is rated Zacks Rank #2 (Buy). See the full list of today’s Zacks #1 Rank stocks here.

• USANA Health Sciences’ 2026 EPS estimates have increased from $1.90 to $2.00 in the past two months, though its shares have dropped 38.7% over the last six months. The company surpassed earnings expectations in three of the last four quarters, with an average surprise of 21.92%.
• Catalyst Pharmaceuticals’ 2026 EPS projections have risen from $2.54 to $2.59 in the last 60 days, and its stock has climbed 20.8% over six months. The company beat earnings estimates in all four recent quarters, averaging a 35.19% positive surprise.
• ALX Oncology Holdings’ projected 2026 loss per share has improved from $1.21 to $0.88 over the past two months, and its shares have surged 91.6% in six months. However, it missed earnings expectations in each of the last four quarters, with an average negative surprise of 12.82%.

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