A Phase 2/3 interventional study of ACP-204 and Placebo in Alzheimer's Disease Psychosis, sponsored by ACADIA Pharmaceuticals Inc.. Recruiting at 155 sites in 12 countries. Open to participants aged 55 Years to 95 Years. Per ClinicalTrials.gov, last updated 2026-11-05.
Sponsored by ACADIA Pharmaceuticals Inc. · Phase 2/3, Interventional, and Treatment
This is a master protocol for 3 independent, seamlessly enrolling, multicenter, randomized, double-blind, placebo-controlled, parallel-group studies in patients with ADP
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).
136 studies on the registry are indexed under Hallucinations; 35 are open to participants now.
This study's planned enrollment of 1,074 is above the median of 48 across 118 interventional studies indexed under Hallucinations.
Browse Hallucinations studies →ACADIA Pharmaceuticals Inc. is the lead sponsor of 41 studies on the registry; 5 are open to participants now.
Of its 26 completed or terminated interventional studies of FDA-regulated products, 24 (92%) have results posted.
Counted across the registry records on this site, refreshed daily.
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Exclusion Criteria:
Additional inclusion/exclusion criteria apply. Subjects will be evaluated at screening to ensure that all criteria for study participation are met.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
MMSE and MoCA
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Administration once daily at approximately the same time of day, with or without food
Drug: ACP-204
Administration once daily at approximately the same time of day, with or without food
Drug: ACP-204
Administration once daily at approximately the same time of day, with or without food
Drug: Placebo
ACP-204 is a potent and selective antagonist/inverse agonist of 5-hydroxytryptamine (serotonin) receptor subtype 2A.
ACP-204 matching placebo
Scale for the Assessment of Positive Symptoms-Hallucinations and Delusions subscales (SAPS-H+D) total score change from baseline (Substudies 1, 2A, 2B)
The SAPS-H+D subscales are a measure of two psychotic symptoms: hallucinations and delusions. The SAPS-H+D total score is the sum of the scores of the Hallucinations and Delusions subscales. The hallucinations domain score (SAPS-H) is the sum of the 7 hallucinations item scores, and the delusions domain core (SAPS-D) is the sum of the 13 delusions item scores.
Time frame: From baseline to Week 6
Clinical Global Impression-Severity in the ADP context (CGI-S-ADP) score
The CGI-S scale is a clinician-rated, 7-point scale that is designed to rate the severity of the subject's symptoms at the time of assessment using the Investigator's judgment and past experience with subjects who have the same disorder. The CGI-S-ADP scale is the CGI-S scale applied in the ADP context, in which hallucinations and delusions are the symptoms of interest.
Time frame: Baseline to Week 6
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Showing the first 100 of 155 sites across 12 countries. Choose a country and city above to see the rest.
Plan to share: No
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Remlifanserin