This section highlights FDA-related milestones and regulatory updates for drugs developed by ACADIA Pharmaceuticals (ACAD).
Over the past two years, ACADIA Pharmaceuticals has reported clinical trial outcomes, regulatory submissions, approvals, and other FDA events for drugs and therapies such as
Trofinetide, ACP-711, ACP-101, and NUPLAZID. For definitions of regulatory abbreviations such as NDA, BLA, or PDUFA, see the event status legend.
Select a button below to view the list of FDA events for that drug.
Trofinetide FDA Regulatory Timeline and Events
Trofinetide is a drug developed by ACADIA Pharmaceuticals for the following indication: Rett Syndrome.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- Trofinetide
- Announced Date:
- March 2, 2026
- Indication:
- Rett Syndrome
Announcement
Acadia Pharmaceuticals Inc y announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) informed the company it has formally adopted a negative opinion regarding the Marketing Authorization Application for trofinetide for the treatment of Rett syndrome in patients two years of age and older.
AI Summary
Acadia Pharmaceuticals said the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency has formally adopted a negative opinion on its Marketing Authorization Application for trofinetide to treat Rett syndrome in patients two years of age and older. The CHMP decision advises against approval in the European Union at this time.
Trofinetide is a synthetic analog of part of insulin‑like growth factor 1 and is approved in the United States, Canada and Israel as the first and only treatment for Rett syndrome. Rett syndrome is a severe neurodevelopmental disorder that can include loss of purposeful hand use, loss of speech, repetitive hand movements and gait problems; many individuals require round‑the‑clock care.
Families and caregivers had hoped for EU approval. Acadia confirmed it received formal notice of the negative opinion from the CHMP and will consider the implications going forward.
Read Announcement- Drug:
- Trofinetide
- Announced Date:
- December 12, 2025
- Indication:
- Rett Syndrome
Announcement
Acadia Pharmaceuticals Inc announced that the U.S. Food and Drug Administration (FDA) has approved DAYBUE® STIX (trofinetide) for oral solution, a dye- and preservative-free powder formulation of trofinetide for the treatment of Rett syndrome in adult and pediatric patients two years of age and older.
AI Summary
Acadia Pharmaceuticals announced that the U.S. Food and Drug Administration has approved DAYBUE STIX (trofinetide) for oral solution, a dye- and preservative-free powder formulation for treating Rett syndrome in adults and pediatric patients aged two years and older. The powder is intended to be mixed into water-based liquids, letting caregivers adjust taste and dose volume to suit individual needs.
The approval is supported by the LAVENDER study results for the original oral solution and a bioequivalence study showing comparable drug exposure between formulations. Because of this, DAYBUE STIX is expected to offer the same efficacy and safety profile as the existing oral solution.
DAYBUE STIX will be available on a limited basis in the first quarter of 2026 and more broadly in the early second quarter of 2026. The current oral solution formulation will remain available for patients and caregivers who prefer it.
Read Announcement- Drug:
- Trofinetide
- Announced Date:
- March 5, 2025
- Indication:
- Rett Syndrome
Announcement
Acadia Pharmaceuticals Inc. announced that the journal Medpublished results from the open-label study, DAFFODIL™, evaluating the safety, tolerability and exploratory efficacy of DAYBUE® (trofinetide) in girls ages two to four living with Rett syndrome (n = 15).
AI Summary
Acadia Pharmaceuticals announced that the journal Med published results from its open-label DAFFODIL™ study evaluating DAYBUE® (trofinetide) in girls ages two to four with Rett syndrome. In this study of 15 participants, researchers examined the safety, tolerability, and exploratory efficacy of the drug in a younger population. Findings indicated that DAYBUE maintained a safety profile similar to that observed in older patients studied in previous trials. The study offers essential insights into treatment plans and dosing strategies for children who typically begin experiencing symptoms very early in life, leading to challenges with communication and motor skills. Overall, the DAFFODIL study reinforces trofinetide’s potential role in addressing the complex needs of pediatric patients with Rett syndrome and supports its long-term use as a safe treatment option. These results help to guide future studies and clinical practices for managing this rare disorder.
Read Announcement- Drug:
- Trofinetide
- Announced Date:
- July 18, 2024
- Indication:
- Rett Syndrome
Announcement
Acadia Pharmaceuticals Inc announced that the journal Med published results from two open-label extension studies, LILAC-1™ and LILAC-2™, which showed that patients treated with DAYBUE™ who completed these studies experienced improvement in Rett symptoms as measured by the Rett Syndrome Behaviour Questionnaire (RSBQ).
AI Summary
Acadia Pharmaceuticals announced that the journal Med recently published results from two open‐label extension studies, LILAC-1 and LILAC-2, evaluating DAYBUE treatment in patients with Rett syndrome. The studies showed that patients who completed long-term treatment with DAYBUE experienced significant improvements in their symptoms, as measured by the Rett Syndrome Behaviour Questionnaire (RSBQ). In LILAC-1, a 40-week study following the initial Phase 3 LAVENDER trial, patients who continued on DAYBUE, as well as those who switched from placebo, saw a similar reduction in RSBQ scores. LILAC-2 further supported these findings over a 32-month period, with a majority of patients reporting at least a 10% improvement in their RSBQ scores. These results provide deeper insight into the long-term safety and potential benefits of DAYBUE for managing Rett syndrome.
Read Announcement- Drug:
- Trofinetide
- Announced Date:
- June 18, 2024
- Indication:
- Rett Syndrome
Announcement
Acadia Pharmaceuticals, Inc. announced that interim data from the open-label real-world LOTUS™ study will be presented at the 2024 International Rett Syndrome Foundation (IRSF) Annual Scientific Meeting, being held this week in Westminster, Colorado.
AI Summary
Acadia Pharmaceuticals announced that interim data from its real-world LOTUS study will be shared at the 2024 International Rett Syndrome Foundation Annual Scientific Meeting in Westminster, Colorado this week. The open-label study gathers caregiver-reported insights on the effectiveness and tolerability of DAYBUE (trofinetide) in patients with Rett syndrome. Early results indicate that many caregivers observed improvements in areas such as nonverbal communication, alertness, and social interaction within one month of treatment. The findings also shed light on real-life strategies used by caregivers to manage gastrointestinal side effects, including diarrhea, by adjusting doses and implementing diarrhea management plans. These interim results support the benefits seen in previous clinical trials and provide useful information for both families and clinicians managing Rett syndrome.
Read Announcement
ACP-711 FDA Regulatory Events
ACP-711 is a drug developed by ACADIA Pharmaceuticals for the following indication: GABRA3 modulators.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- ACP-711
- Announced Date:
- October 2, 2025
- Indication:
- GABRA3 modulators
Announcement
Acadia Pharmaceuticals Inc announced one late-breaker oral platform presentation and two poster presentations to be presented at the International Congress of Parkinson's Disease and Movement Disorders® being held October 5-9, 2025, in Honolulu, Hawaii.
AI Summary
Acadia Pharmaceuticals Inc. announced that it will deliver a late-breaker oral platform presentation and two poster presentations at the International Congress of Parkinson’s Disease and Movement Disorders®, to be held October 5–9, 2025, in Honolulu, Hawaii.
The late-breaker talk, “Mechanism of Action, Preclinical Efficacy, and Safety Evaluation of SAN711/ACP-711,” will take place on October 8 from 12:00–1:00 p.m. HST. ACP-711 is a novel GABAA subunit α3 selective modulator under investigation for essential tremor, and Acadia will share its preclinical efficacy, safety and mechanism of action findings.
The first poster, scheduled for October 7 at 12:18 p.m. HST, presents the design of the Phase 2, double-blind, placebo-controlled ACP-204 study in adults with Lewy body dementia psychosis. The second poster, at 12:06 p.m. HST the same day, offers encore post-hoc analysis data on duration of illness and response to NUPLAZID® (pimavanserin) in Parkinson’s disease psychosis.
Read Announcement- Drug:
- ACP-711
- Announced Date:
- March 3, 2025
- Indication:
- GABRA3 modulators
Announcement
Acadia Pharmaceuticals Inc. announced the successful completion of the two originally planned cohorts in their Phase 1 multiple-ascending-dose MAD study (EUCT: 2024-514514-12-00) of ACP-711, formerly SAN711, in healthy volunteers.
AI Summary
Acadia Pharmaceuticals announced the successful completion of two initially planned cohorts in the Phase 1 multiple ascending dose (MAD) study (EUCT: 2024-514514-12-00) of ACP-711, formerly known as SAN711, in healthy volunteers. The study demonstrated that ACP-711 was safe and generally well tolerated, with all participants finishing the trial and no serious adverse events reported. Most of the observed adverse events were mild, and there were no issues related to safety laboratories, cardiovascular functions, or neurological assessments. Based on these promising results, Acadia plans to seek regulatory approval to extend the study by testing higher repeated doses and including elderly healthy volunteers. This advancement marks an important step in developing ACP-711 as a potential treatment for essential tremor, reflecting a positive outlook for its future clinical evaluation.
Read Announcement
ACP-101 FDA Regulatory Events
ACP-101 is a drug developed by ACADIA Pharmaceuticals for the following indication: For the treatment of hyperphagia in Prader-Willi syndrome (PWS).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- ACP-101
- Announced Date:
- September 24, 2025
- Indication:
- For the treatment of hyperphagia in Prader-Willi syndrome (PWS).
Announcement
Acadia Pharmaceuticals Inc. announced top-line results from the Phase 3 COMPASS PWS trial evaluating the efficacy and safety of intranasal carbetocin (ACP-101) in patients with hyperphagia in Prader-Willi syndrome (PWS).
AI Summary
Acadia Pharmaceuticals announced top-line results from the Phase 3 COMPASS PWS trial testing intranasal carbetocin (ACP-101) in people with Prader-Willi syndrome (PWS) who struggle with hyperphagia. After 12 weeks, carbetocin did not show a statistically significant benefit over placebo on the primary measure, the Hyperphagia Questionnaire for Clinical Trials (HQ-CT). No secondary endpoints separated from placebo either.
The safety and tolerability of intranasal carbetocin matched previous studies, with a low rate of adverse events. Elizabeth H. Z. Thompson, Ph.D., Acadia’s Head of Research and Development, expressed disappointment for PWS patients and their families. Given the trial’s outcome, the company will not pursue further development of intranasal carbetocin but plans to share a detailed data summary with the PWS community in the future.
COMPASS PWS enrolled 175 children and adults aged 5 to 30 in a 12-week, randomized, double-blind, placebo-controlled design, dosing 3.2 mg three times daily. Despite unmet expectations, the study adds important insights for future research in PWS.
Read Announcement
NUPLAZID (Pimavanserin) FDA Regulatory Events
NUPLAZID (Pimavanserin) is a drug developed by ACADIA Pharmaceuticals for the following indication: Hallucinations and Delusions Associated with Dementia-Related Psychosis.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- NUPLAZID (Pimavanserin)
- Announced Date:
- June 9, 2025
- Indication:
- Hallucinations and Delusions Associated with Dementia-Related Psychosis
Announcement
Acadia Pharmaceuticals Inc announced that the U.S. Court of Appeals for the Federal Circuit affirmed a decision issued by the U.S. District Court for the District of Delaware in December 2023 confirming validity of the NUPLAZID® (pimavanserin) '740 composition of matter patent.
AI Summary
Acadia Pharmaceuticals Inc. announced that the U.S. Court of Appeals for the Federal Circuit has upheld the U.S. District Court for the District of Delaware’s decision, affirming the validity of the NUPLAZID® (pimavanserin) '740 composition of matter patent. This ruling ensures that the patent remains protected until 2030. According to the court’s reasoning, an earlier filed and issued claim cannot be invalidated by a later, earlier-expiring reference claim when both share a common priority date.
The decision is a key victory for Acadia, reinforcing its intellectual property portfolio and ensuring solid market protection for NUPLAZID®. This outcome backs the company’s commitment to safeguarding its innovative therapies designed to address significant, unmet medical needs, thereby providing confidence in the strength and durability of its patent protections.
Read Announcement
