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Pimavanserin vs. Quetiapine for Parkinson's Psychosis

This study is comparing two medications, pimavanserin and quetiapine, for treating psychosis (seeing or hearing things that aren't real, or believing things that aren't true) in people with Parkinson's disease. Pimavanserin is the only FDA-approved medication for this condition, while quetiapine is commonly used. Researchers want to see which medication works better to reduce psychosis symptoms. You might be able to join if you are a veteran, 40 years or older, have Parkinson's disease with psychosis, and your Parkinson's medications are stable. The study aims to enroll 358 participants. Success will be measured by how much your psychosis symptoms improve after 8 weeks. The current status of this study is unclear.

Study design
This is a randomized, double-blind study comparing two treatments. About 358 participants will be randomly assigned to receive either pimavanserin or quetiapine.
What's involved
You would have assessments at baseline, week 3, week 5, and week 8 after starting the study. These include evaluations of psychosis, sleep, caregiver burden, functioning, motor abilities, and thinking skills.
Compensation
Not stated in the trial record.
Follow-up
Assessments will be collected up to 8 weeks after randomization.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT04373317

Pimavanserin vs. Quetiapine for Treatment of Parkinson's Psychosis

Recruiting
PHASE4Ages 40+InterventionalTreatment
VA Office of Research and Development
~358 participants
Updated 2026-08-19 on ClinicalTrials.gov
What's tested:PimavanserinQuetiapine

At a glance

Recruiting sites
9 of 24 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
CGI-I Psychosis
Measured over 8 Weeks

Conditions

Parkinson's Disease Psychosis

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Parkinson Disease

NCT04373317

Where you'd take part

This study runs at 24 sites. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA

    Philadelphia, Pennsylvaniastudy coordinator listed

    Recruiting

  • Louis Stokes VA Medical Center, Cleveland, OH

    Cleveland, Ohiostudy coordinator listed

    Recruiting

  • Michael E. DeBakey VA Medical Center, Houston, TX

    Houston, Texasstudy coordinator listed

    Recruiting

  • Minneapolis VA Health Care System, Minneapolis, MN

    Minneapolis, Minnesotastudy coordinator listed

    Recruiting

  • Philadelphia MultiService Center, Philadelphia, PA

    Philadelphia, Pennsylvaniastudy coordinator listed

    Recruiting

  • Rocky Mountain Regional VA Medical Center, Aurora, CO

    Aurora, Coloradostudy coordinator listed

    Recruiting

  • VA Loma Linda Healthcare System, Loma Linda, CA

    Loma Linda, Californiastudy coordinator listed

    Recruiting

  • VA Palo Alto Health Care System, Palo Alto, CA

    Palo Alto, Californiastudy coordinator listed

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

Study leadership

  • Daniel Weintraub, MD · STUDY_CHAIR · Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA

Who to contact

Daniel Weintraub, MD
[email protected]
(215) 823-5800 · ext. 5934
Email the study team

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Eligibility criteria

Inclusion

Veteran
Diagnosis of Parkinson's Disease consistent with UK Parkinson's Disease Society Brain Bank Clinical Diagnostic Criteria
Psychosis \[with Neuropsychiatric Inventory (NPI) hallucinations (B) or delusions (A) score 4 or greater\]
Stable dose of PD medications for at least 2 weeks
If on an acetylcholinesterase inhibitor (AChEI) initially prescribed at least 3 months prior and stable dose (no dose or medication change) for past month
Informed other must provide informed consent and agree to attend all study visits. The informed other must be at least 18 years of age and have regular contact with the patient (on average at least 4 days per week and at least 2 hours per day, or at least 3 days per week and at least 4 hours per day, that is with patient) via in-person, video, or telephone
English-speaking
Age 18 years or older
Must have regular contact with the patient (on average at least 4 days per week, and at least 2 hours per day, or at least 3 days per week and at least 4 hours pr day, that is with patient) via in-person, video, or telephone
Agree to attend all study visits
Be able to provide informed consent
English-speaking

Exclusion

Psychosis symptoms severe enough to preclude enrollment in a clinical trial and require prompt clinical care instead
Treatment with quetiapine \>50 mg/day or pimavanserin in the past 3 months, or quetiapine 50 mg/day or another antipsychotic in the past week prior to study randomization
Deep brain stimulation (DBS) surgery within 3 months or has had stimulator adjustments in the previous 2 weeks
History of a psychotic disorder prior to PD, including bipolar disorder, schizophrenia, schizoaffective disorder, and major depressive disorder with psychotic features, if it is thought to be the cause of the current psychosis symptoms
Suspected atypical parkinsonian disorder or dementia with Lewy bodies (DLB)
Psychosis secondary to other toxic or metabolic disorder
History of long QT syndrome
Documented chart evidence indicating persistent hypoglycemia, hypokalemia, hypomagnesemia that would put patient at increased risk for QTc prolongation.
History of ventricular arrhythmias, except when treated with an implantable cardioverter defibrillator (ICD) or pacemaker, or untreated or unstable atrial fibrillation/flutter
Currently taking medications that are moderate or strong CYP3A4 inducers or strong CYP3A4 inhibitors
Concomitant use of drugs that prolong the QTc interval with a known risk of Torsades de Pointes
Comorbid medical condition determined too severe by Site Investigator to allow participation in clinical trial
Failure to tolerate quetiapine or pimavanserin previously
Severe cognitive impairment (MoCA score \<5)
Nursing home placement at screening or planned placement during the study, unless approved by study Co-Chairs. Approval will depend upon nursing facility agreement to receive, return, and administer medications or allow participant to self-administer study medications; appropriate IO availability; and transportation availability for study visits.
Currently enrolled in another therapeutic or interventional study
Pregnant, or a female of child-bearing potential who is unwilling to use a reliable form of contraception

What this trial measures

  • CGI-I Psychosis8 Weeks

    The Clinical Global Impressions (CGI) scale is a brief, well-established research rating tool used to quantify and track patient progress and treatment response over time. The CGI comprises two measures, one of which is Improvement (CGI-I) from the initiation of treatment. It is scored 1 to 7. The CGI-I is used to assess how much the patient's illness has improved or worsened relative to baseline when the intervention was started (1-Very much improved, 2-Much improved, 3-Minimally improved, 4-No change, 5-Minimally worse, 6-Much worse, 7-Very much worse). The CGI-I can also be used to assess specific domains, including psychosis (this study's primary outcome) and parkinsonism (a secondary outcome). During the 8 weeks, the CGI-I (for psychosis, hereafter simply referred to as the CGI-I) will be administered to all participants at 3 weeks, 5 weeks, and 8 weeks following a CGI-I baseline interview to assess clinical improvement in psychosis.