Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Recruiting

A Study Testing ACP-204 Tartrate Compared to Placebo for Adults with Lewy Body Dementia Psychosis

Fast replyInvestigationalNo placebo
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is looking at Lewy Body Dementia Psychosis, a condition where people with a type of dementia called Lewy body dementia experience hallucinations or false beliefs. Lewy body dementia is a brain disorder that affects thinking, movement, and behavior, and when it includes seeing or hearing things that are not there or having unusual beliefs, it is called Lewy Body Dementia Psychosis. The study will test a medication called ACP-204 in capsule form, which will be given by mouth. Some participants will receive placebo instead of the actual medication. The purpose of this study is to find out if ACP-204 works to reduce the symptoms of hallucinations and false beliefs in people with this condition, and to compare two different doses of the medication to see which one works better.

During the study, participants will take either ACP-204 at a dose of 30 milligrams daily, ACP-204 at a dose of 60 milligrams daily, or placebo for a period of six weeks. The main goal is to see if there is an improvement in symptoms related to hallucinations and false beliefs by measuring changes using a special rating scale designed for people with Lewy Body Dementia Psychosis. This scale looks at specific symptoms like seeing things that are not really there or having beliefs that do not match reality.

The study is designed to be double-blind, which means that neither the participants nor the doctors will know who is receiving the actual medication and who is receiving placebo during the treatment period. The treatment will last for six weeks, and doctors will check how well the medication works by comparing the symptoms at the beginning of the study to the symptoms at the end of the six-week period. This research is intended to help understand whether ACP-204 can be a helpful treatment option for adults living with Lewy Body Dementia Psychosis.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Treatment period begins

    Upon joining the study, you will be assigned to one of three treatment groups. This assignment will be done randomly, similar to flipping a coin.

    You may receive either ACP-204 30 mg capsules, ACP-204 60 mg capsules, or placebo capsules. A placebo is a capsule that looks identical to the active treatment but contains no active medicine.

    Neither you nor the study doctor will know which treatment you are receiving. This is called a double-blind design and helps ensure accurate results.

    All capsules are taken by mouth.

  2. Step 2

    Daily medication administration

    You will take your assigned capsules daily throughout the treatment period.

    The exact dosing schedule and frequency will be provided by the study staff based on your assigned group.

    It is important to take the capsules as instructed each day.

  3. Step 3

    Assessment at baseline

    At the beginning of the treatment period, your symptoms will be evaluated using a specific assessment tool.

    This assessment focuses on symptoms such as hallucinations (seeing or hearing things that are not there) and delusions (false beliefs).

    The assessment is called the Scale for the Assessment of Positive Symptoms for Lewy Body Dementia Psychosis, which contains 9 questions.

    This baseline measurement will be used to compare any changes in your symptoms during the study.

  4. Step 4

    Week 6 assessment

    After 6 weeks of taking the study medication, you will undergo the same symptom assessment again.

    The study staff will measure any changes in your symptoms compared to the baseline assessment.

    This is the main time point for evaluating whether the treatment has had an effect on your symptoms.

  5. Step 5

    Completion of treatment period

    After the Week 6 assessment, the main treatment period of the study will be complete.

    Additional follow-up visits or assessments may be scheduled as part of the study procedures.

    The study staff will provide instructions regarding any further steps or the end of your participation.

Who can join the trial?

6 criteria

  • You must be 55 years of age or older but younger than 85 years at the time of the screening visit
  • You can be male or female
  • You must be living in the community at home or in a care facility if allowed by local rules
  • You must be able to provide written informed consent, which means you agree in writing to take part in the study after understanding what it involves. If you are not able to provide consent yourself, a legally authorized representative (someone legally allowed to make decisions for you) or your study partner or caregiver must provide written consent on your behalf, and you must provide written agreement if you are able to do so
  • You must meet the medical criteria for Parkinson's disease with dementia, which is a condition where Parkinson's disease leads to problems with memory and thinking, or you must meet the criteria for probable dementia with Lewy bodies, which is a type of dementia caused by abnormal protein deposits in the brain
  • You must meet the criteria for psychosis, which means experiencing things that are not real such as seeing or hearing things that others do not, or having false beliefs, and these symptoms must be related to your memory and thinking problems

Who cannot join the trial?

3 criteria

  • The study does not list specific exclusion criteria in the provided information, meaning details about who cannot participate are not available in this data
  • Generally, clinical trials may exclude patients based on other medical conditions, medications they are taking, or safety concerns, but these specific details are not provided here
  • If you are interested in this study, the research team would need to provide the complete list of reasons why someone might not be able to participate
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

  • ACP-204

    is an investigational medication being studied for the treatment of psychosis in people with Lewy body dementia. Psychosis can include symptoms like hallucinations (seeing or hearing things that are not there) and delusions (false beliefs). This medication is being tested to see if it can help reduce these symptoms in patients with this type of dementia.

  • Placebo

    is an inactive substance that looks like the real medication but contains no active drug. It is used in this study to compare against the actual medication to determine if the medication truly works. Some participants will receive the placebo instead of the active medication.

What is already known about the treatment

ACP-204 – ACP-204 is an investigational medication currently being studied in clinical trials for the treatment of psychosis in people with Lewy Body Dementia, a brain disorder that causes problems with thinking, movement, and behavior. The drug is being tested at two different dose levels (30 mg and 60 mg) given by mouth to see if it can reduce hallucinations and delusions, which are common symptoms where patients see or believe things that are not real. In this phase 2 study, researchers are comparing ACP-204 to a placebo (an inactive pill) to determine if the medication is effective and safe for patients with this condition. The specific way ACP-204 works in the brain has not been detailed in this trial information, but it is being developed specifically to address the psychiatric symptoms associated with Lewy Body Dementia.

Investigated diseases

Lewy Body Dementia – Lewy Body Dementia is a brain disorder that occurs when abnormal protein deposits called Lewy bodies build up in nerve cells in the brain. These deposits affect chemicals in the brain and lead to problems with thinking, movement, behavior, and mood. People with this condition experience changes in their ability to think clearly and pay attention, which can vary significantly from day to day or even hour to hour. Visual hallucinations, where people see things that are not there, are common and occur early in the disease. Movement problems similar to Parkinson's disease often develop, including slow movement, stiff muscles, and trembling. The condition progresses over time, gradually affecting more areas of brain function and daily activities.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-521710-25-00Protocol codeACP-204Estimated enrolment180 patientsSponsorAcadia Pharmaceuticals Inc.

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

ClinicalTrials.eu

Every clinical trial in Europe, in plain language.

Explore the full ecosystem of clinical research in Europe.

Search trials

Legal notice · Published by CTIN POLAND sp. z o.o., ul. rtm. Witolda Pileckiego 67/109, 02-781 Warsaw, Poland · KRS 0001111334 · REGON 528919042 · NIP 9512598637

© 2026 Clinical Trials EU – European Clinical Trials Information Network

GDPR compliance, ISO 9001 and ISO 27001 certified (LL-C Certification)

On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).