Recruiting
Phase 2
Phase 3

ACP-204

Sponsor:

ACADIA Pharmaceuticals Inc.

Code:

NCT06159673

Conditions

Alzheimer's Disease Psychosis

Eligibility Criteria

Sex: All

Age: 55 - 70+

Healthy Volunteers: Not accepted

Interventions

ACP-204

Placebo

Study Details

Brief summary:

This is a master protocol for 3 independent, seamlessly enrolling, multicenter, randomized, double-blind, placebo-controlled, parallel-group studies in patients with ADP

  • Substudy 1 (Phase 2) will evaluate efficacy and dose response of ACP-204 30 and 60 mg vs placebo. This substudy will be initiated first.
  • Substudies 2A and 2B (both: Phase 3) will be confirmatory studies of either both doses (ACP-204 30 and 60 mg, respectively) or a single dose from Part 1 vs placebo. Substudies 2A and 2B will be performed independently of each other and will commence after enrollment of Part 1.

All 3 substudies will be analyzed independently of each other.

Each substudy individually will consist of a screening period (up to 49 days); a double-blind treatment period (6 weeks); a safety follow-up period (30 days) for patients not rolling over into an open-label extension study; and vital status follow-up (for patients who terminated their substudy early).

Conditions

Alzheimer's Disease Psychosis

Study ID

NCT06159673

Start date

Nov 14, 2023

Status verified date

Jun, 2026

Completion date

Feb, 2028

Anticipated

Primary completion date

Jan, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 55 - 70+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Is male or female and ≥55 and ≤95 years of age living in the community or in an institutionalized setting
  • Meets clinical criteria for possible or probable AD based on the 2011 National Institute on Aging-Alzheimer Association (NIA-AA) criteria
  • Meets the revised criteria for psychosis in major or mild neurocognitive disorder established by the International Psychogeriatrics Association (IPA)
  • Has either blood-based biomarker or documented evidence (e.g. positron emission tomography, cerebrospinal fluid biomarker) indicating amyloid plaque deposition and neuropathologic change consistent with AD
  • Has a prior magnetic resonance imaging or computed tomography scan of the brain that is consistent with the diagnosis of AD
  • Meets revised criteria for psychosis in major or mild neurocognitive disorder as per International Psychogeriatrics Association
  • MMSE score ≥6 and ≤24
  • Psychotic symptoms for at least 2 months
  • Lives in a stable place of residence and there are no plans to change living arrangements
  • Has a designated study partner/caregiver
  • Able to complete all study visits with a study partner/caregiver
  • Must be on a stable dose of cholinesterase inhibitor or memantine, if applicable

Exclusion Criteria:

  • Requires treatment with a medication prohibited by the protocol
  • Is in hospice and receiving end-of-life palliative care, or has become bedridden
  • Requires skilled nursing care
  • Psychotic symptoms that are primarily attributable to delirium, substance abuse, or a medical or psychiatric condition other than dementia
  • Known history of cerebral amyloid angiopathy, epilepsy, central nervous system neoplasm, or unexplained syncope
  • Atrial fibrillation
  • Symptomatic orthostatic hypotension
  • Protocol-defined exclusionary clinical laboratory findings
  • Treatment with anti-tau therapy or donanemab within 2 months prior to Screening

Additional inclusion/exclusion criteria apply. Subjects will be evaluated at screening to ensure that all criteria for study participation are met.

Study Design

Enrollment

1074 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: ACP-204 30 mg

Administration once daily at approximately the same time of day, with or without food

experimental: ACP-204 60 mg

Administration once daily at approximately the same time of day, with or without food

placebo comparator: Placebo

Administration once daily at approximately the same time of day, with or without food

Interventions

ACP-204

ACP-204 is a potent and selective antagonist/inverse agonist of 5-hydroxytryptamine (serotonin) receptor subtype 2A.

Placebo

ACP-204 matching placebo

Primary outcome measure

  • Scale for the Assessment of Positive Symptoms-Hallucinations and Delusions subscales (SAPS-H+D) total score change from baseline (Substudies 1, 2A, 2B) [ Time Frame: From baseline to Week 6 ]

Central Contacts and Locations

Central contacts

Christine Murphy

858-465-7480cmurphy@acadia-pharm.com

Kristen White

813-838-6468kristen.white@acadia-pharm.com

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More Information

Sponsor

ACADIA Pharmaceuticals Inc.

Last update posted

Aug 31, 2026

Last verified

Jun, 2026

Keywords

  • Alzheimer's disease psychosis
  • Hallucinations
  • Delusions

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-25. This information was provided to ClinicalTrials.gov by ACADIA Pharmaceuticals Inc. on 2026-08-31. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.