Acadia Pharmaceuticals Inc. (ACAD) hit a regulatory roadblock in Europe after the Committee for Medicinal Products for Human Use (CHMP) at the European Medicines Agency delivered a negative vote on the company's Marketing Authorization Application for trofinetide, a treatment for Rett syndrome. The decision came following Acadia's recent oral explanation to the committee.

But this isn't necessarily the end of the road. Acadia intends to request a re-examination of the opinion once the CHMP vote is formally adopted in February. Under EU regulations, companies have the right to challenge these decisions, and Acadia appears ready to fight for approval.

"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," said Catherine Owen Adams, Chief Executive Officer.

How the Re-Examination Process Works

Here's how the appeals process plays out: Companies have 15 calendar days after receiving the negative opinion to request a re-examination. They then have 60 days to submit the grounds for that request. Once submitted, the CHMP has up to 60 days to reconsider its position.

The stakes are significant because trofinetide, marketed as Daybue in the US, represents a genuine breakthrough. In March 2023, the FDA approved Daybue for Rett syndrome in adult and pediatric patients two years of age and older, making it the first and only drug approved for this condition.

Rett syndrome is a rare genetic neurological and developmental disorder that causes a progressive loss of motor skills and language. The condition primarily affects females, and until Daybue's approval, no approved treatments existed.

Recent Setback in Another Program

The European rejection comes on the heels of another disappointment for Acadia. In September 2024, the company released topline results from its Phase 3 COMPASS PWS trial evaluating intranasal carbetocin (ACP-101) in patients with hyperphagia in Prader-Willi syndrome.

The trial didn't go as hoped. Intranasal carbetocin failed to demonstrate a statistically significant improvement over placebo on the primary endpoint, which measured change from baseline to Week 12 on the Hyperphagia Questionnaire for Clinical Trials. The drug also didn't separate from placebo on any secondary endpoints.

Shares of Acadia Pharmaceuticals (ACAD) were down 6.12% at $24.53 at the time of publication on Tuesday.