ACAD Plans Re-Examination After CHMP Rejects Rett Syndrome Drug in EU

Acadia Pharmaceuticals ACAD announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has formally adopted a negative opinion recommending against the approval of trofinetide for the treatment of Rett syndrome in patients aged two years and older in the EU.

The decision was expected as the CHMP had informed the company of a negative trend vote on its marketing application for trofinetide to treat Rett syndrome in early February. Following the formal adoption of the opinion, Acadia reviewed the CHMP’s grounds for refusal in detail and plans to request a re-examination. The regulatory setback has delayed the potential approval of trofinetide in the EU.

Although the pivotal LAVENDER study met its co-primary and key secondary endpoints, the CHMP issued the refusal, citing several perceived limitations. These included the view that the treatment effect of trofinetide after 12 weeks, while measurable, was modest in magnitude; that the study did not capture all core symptoms of Rett syndrome; and that the assessment of longer-term outcomes may have been affected by patient discontinuations over time. Acadia believes this feedback offers valuable insights as it prepares for the planned re-examination.

Rett syndrome is a rare neurodevelopmental disorder affecting about one in 10,000-15,000 female births worldwide. After a period of apparently normal early development, symptoms typically emerge between six and 18 months, followed by the loss of acquired skills. While some stabilization may occur, patients often experience ongoing motor deterioration over time.

The FDA approved trofinetide as the first and only treatment for Rett syndrome in adults and pediatric patients aged two years and older in 2023. The drug is marketed under the brand name Daybue in the United States.

In the past six months, shares of Acadia have lost 10.9% compared with the industry’s rally of 19.7%.

ACAD's Marketed Drugs Expected to Aid Growth

Despite the latest hurdle, Acadia remains positioned for long-term growth, supported by its lead product, Nuplazid and Daybue in the United States. The company expects to generate around $1.7 billion in combined net sales by 2028, including $1 billion for Nuplazid and $700 million for Daybue.

Nuplazid is the first and only FDA-approved treatment for hallucinations and delusions associated with Parkinson’s disease psychosis in the United States. The drug enjoys patent protection in the United States until 2038, which gives it a long runway for revenue generation by protecting against generic erosion. In 2025, Nuplazid recorded $680.1 million in sales, up 12% year over year, driven primarily by volume growth.

Since its launch in 2023, Daybue has been witnessing encouraging sales uptake in the United States. In 2025, Daybue recorded $391.4 million in sales, up 12% year over year, driven by growth in the drug’s unit sales as the company shipped it to more unique patients.

In late 2025, the FDA approved Daybue Stix (trofinetide) for oral solution, a dye- and preservative-free powder formulation for the treatment of Rett syndrome in adults and pediatric patients aged two years and older. The new product expands the Daybue franchise, which remains the only FDA-approved treatment option for this indication.

Acadia plans a limited launch of Daybue Stix during the first quarter of 2026, followed by broader availability in the second quarter. The company will continue to offer the current oral solution alongside the new formulation, strengthening its positioning in the Rett syndrome treatment market.

ACADIA Pharmaceuticals Inc. Price and Consensus

ACADIA Pharmaceuticals Inc. price-consensus-chart | ACADIA Pharmaceuticals Inc. Quote

ACAD's Zacks Rank & Stocks to Consider

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

Some top-ranked stocks in the biotech sector are USANA Health Sciences USNA, Catalyst Pharmaceuticals CPRX and ALX Oncology Holdings ALXO. While USNA and CPRX sport a Zacks Rank #1 (Strong Buy) each, ALXO carries a Zacks Rank #2 (Buy) at present. You can see the complete list of today’s Zacks #1 Rank stocks here.

Over the past 60 days, estimates for USANA Health Sciences’ 2026 earnings per share (EPS) have risen from $1.90 to $2.00. USNA shares have lost 38.7% over the past six months.

USANA Health Sciences’ earnings beat estimates in three of the trailing four quarters and matched once, with the average surprise being 21.92%.

Over the past 60 days, estimates for Catalyst Pharmaceuticals’ 2026 EPS have risen from $2.54 to $2.59. CPRX shares have soared 20.8% over the past six months.

Catalyst Pharmaceuticals’ earnings beat estimates in each of the trailing four quarters, with the average surprise being 35.19%.

Over the past 60 days, estimates for ALX Oncology Holdings’ 2026 loss per share have narrowed from $1.21 to 88 cents. ALXO shares have rallied 91.6% over the past six months.

ALX Oncology Holdings’ earnings missed estimates in each of the trailing four quarters, with the average negative surprise being 12.82%.

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