ACP-204, an inverse agonist at the 5-HT2A receptor, builds upon the learnings of pimavanserin (Nuplazid) in the treatment of neuropsychiatric symptoms.
In recent news, Acadia Pharmaceuticals announced a phase 2 trial program assessing ACP-204, an inverse agonist, as a potential treatment for patients with Alzheimer disease (AD) psychosis, a condition for which there is no FDA-approved medication. The initial phase 2 study is part of a larger phase 2/3 program that includes 2 other phase 3 studies of identical design.1 1500*3050mm Acp

Randomized, double-blinded, and placebo-controlled in design, the phase 2 study will enroll approximately 318 patients with AD psychosis and follow them over a 6-week treatment period. Patients will receive either 30 or 60 mg of ACP-204 or placebo, with change on the Scale for the Assessment of Positive Symptoms-Hallucinations and Delusions (SAPS-H+D) subscales total score as the primary end point.
The program will seamlessly transition from phase 2 to phase 3, with each of the planned studies to include 378 patients with AD psychosis. Patients who complete the study will have the option to enter a long-term open-label extension phase.
ACP-204 works primarily as an inverse agonist at the 5-HT2A receptor, building upon the learnings of pimavanserin (Nuplazid), Acadia’s FDA-approved medication indicated for patients with Parkinson disease psychosis. To date, the investigational agent has completed phase 1 development, demonstrating a favorable safety and tolerability profile in the doses to be used in the phase 2 study. Overall, the results supported the agent’s target profile as a potential treatment for AD psychosis.2
READ MORE: Building on Momentum: Overviewing Ongoing Efforts from the Alzheimer’s Association
Pimavanserin, originally approved in tablet form, became the first medication marketed for the treatment of hallucinations and delusions associated with psychosis in patients with PD in 2016. It remains the only approved agent to treat the condition. Most recently, the FDA updated the packaging label for the therapy, restating that the phase 3 study that supported its approval included patients with PD psychosis with or without dementia.3 Although no risk information was changed, the therapy’s boxed warning language was further clarified to include patients with PD psychosis who have dementia.
Acadia further pursued an expanded indication of pimavanserin to include the treatment of AD psychosis but was not successful, as the FDA issued a complete response letter to the company in late 2022.4 At the time, the agency noted it could not approve the application as is, and recommended that the company conduct an additional trial in AD psychosis. The supplemental new drug application was supported by data from the phase 2 Study-019 trial (NCT02035553) and the phase 3 HARMONY study (NCT03325556), which assessed the therapy over the course of 43 days and 26 weeks, respectively. HARMONY included 392 patients with various dementia subtypes, including AD, PD dementia, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.
Changes in the Diagnostic Process of Alzheimer Disease: A New Era of Blood-Based Approaches
Episode 103: Advancing Epilepsy Care and Seizure Localization in Pediatrics
FDA Action Update, November 2023: Acceptance, Clearance, and Hold
Episode 102: Potential of Gamma Sensory Stimulation in Alzheimer Disease
Open-Label LILAC-2 Data Demonstrates Trofinetide’s Long-Term Treatment Benefit in Rett Syndrome
Mendelian Randomization Study Suggests Narcolepsy Increases Risk of Heart Failure and Coronary Artery Disease
Changes in the Diagnostic Process of Alzheimer Disease: A New Era of Blood-Based Approaches
Episode 103: Advancing Epilepsy Care and Seizure Localization in Pediatrics
FDA Action Update, November 2023: Acceptance, Clearance, and Hold
Episode 102: Potential of Gamma Sensory Stimulation in Alzheimer Disease
Open-Label LILAC-2 Data Demonstrates Trofinetide’s Long-Term Treatment Benefit in Rett Syndrome

3*0.18mm Acp Mendelian Randomization Study Suggests Narcolepsy Increases Risk of Heart Failure and Coronary Artery Disease