Pimavanserin vs. Quetiapine for the Treatment Parkinson’s Psychosis


Patients with Parkinson's disease (PD) sometimes experience symptoms affecting their movement, such as slowness, tremor, stiffness, and balance or walking problems. Many patients also have other symptoms not related to movement, called non-motor symptoms, which may affect one's mood or emotions, memory or thinking, or cause one to see or hear things that aren't real (hallucinations) or believe things that aren't true (delusions). Hallucinations or delusions, together called psychosis, occur in up to 60% of PD patients at some point in time. Parkinson's disease psychosis can sometimes be associated with decreased quality of life, increased nursing home placement, increased rate of death, and greater caregiver burden. There are approximately 50,000 Veterans with Parkinson's disease receiving care in the VA, and up to 30,000 (60%) of them will experience psychosis at some point in time. Quetiapine is an antipsychotic drug approved by the Food and Drug Administration (FDA) that is the most commonly used medication to treat PD psychosis, but more studies are needed to determine if it works for this condition and is also well tolerated and safe. Pimavanserin is a newer antipsychotic drug approved by the Food and Drug Administration (FDA) specifically to treat PD psychosis, but more studies are needed to determine if it works and its safety. The purpose of this research is to gather additional information on the safety and effectiveness of both Quetiapine and Pimavanserin. By doing this study, the investigators hope to learn which of these medications is the most effective course of treatment for people with PD psychosis. Your individual participation in this research will last approximately 54 weeks.

Full Title of Study: “CSP #2015 – Multicenter, Randomized, Double-blind Comparator Study of Antipsychotics Pimavanserin and Quetiapine for Parkinson”s Disease Psychosis (C-SAPP)”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Triple (Participant, Care Provider, Investigator)
  • Study Primary Completion Date: October 1, 2024


  • Drug: Pimavanserin
    • Pimavanserin is a new antipsychotic agent, and pure 5HT-2A inverse agonist, that was approved by the FDA recently (2016) for the treatment of PDP.
  • Drug: Quetiapine
    • Quetiapine, which is a mixed serotonin and dopamine receptor antagonist but also binds to many other brain receptors (e.g., adrenergic, cholinergic, histaminergic receptors), is by far the most commonly used AP for PDP (at least 70% of prescriptions) and does not require special monitoring.

Arms, Groups and Cohorts

  • Active Comparator: Pimavanserin 34mg
    • All participants assigned to pimavanserin will receive the FDA-approved dose of 34mg (equivalent to 40 mg pimavanserin tartrate) daily without titration; however, because pimavanserin is blinded to quetiapine, participants will undergo sham titration based on tolerability.
  • Active Comparator: Quetiapine
    • Quetiapine extended release will be titrated as shown in the following table. During the 8-week treatment phase, there is a maximum of 6 weeks for titration. Titration Schedule Visit/call Quetiapine Dose (Flexible)Quetiapine Notes Baseline visit (Visit 00)25 mg IR QHSAll participants must be up-titrated to at least 50 mg/day at week 1 Week 1 call (Visit 01)50 mg XR QHSUp-titration Week 3 visit (Visit 03)100 mg XR QHS (requiring two 50-mg quetiapine XR capsules)Up- or down-titration as appropriate based on psychosis symptoms and tolerability Week 5 visit (Visit 05)150 mg quetiapine XR QHSUp- or down-titration as appropriate based on psychosis symptoms and tolerability Week 6 call (Visit 06)200 mg quetiapine XR QHSUp- or down-titration as appropriate based on psychosis symptoms and tolerability

Clinical Trial Outcome Measures

Primary Measures

  • CGI-I Psychosis
    • Time Frame: 8 Weeks
    • CGI-I (for psychosis). 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. It was originally developed to be used in clinical trials on mental health to provide an assessment of the clinician’s view of the patient’s global functioning over time with a study medication. 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).

Secondary Measures

    • Time Frame: 8 Weeks
    • The primary assessment of change in psychosis severity will be the score on the 9-item Parkinson’s disease-adapted Scale for Assessment of Positive Symptoms (SAPS-PD).59 The SAPS-PD scale is designed to assess positive symptoms, including hallucinations, delusions, bizarre behavior, and positive formal thought disorder. A standard clinical interview with probing questions is used to evaluate the participant’s symptoms. Items include: 1) Auditory Hallucinations; 2) Voices Conversing; 3) Somatic or Tactile Hallucinations; 4) Visual Hallucinations; 5) Global Rating of Severity of Hallucinations; 6) Persecutory Delusions; 7) Delusions of Jealousy; 8) Ideas and Delusions of Reference; and 9) Global Rating of Severity of Delusions. Each item is given a score ranging 0 to 5 (0-None, 1-Questionable, 2-Mild, 3-Moderate, 4-Marked, 5-Severe). Thus, total scores for SAPS-PD ranges 0-45.
    • Time Frame: 8 Weeks
    • The Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part III (Motor Examination; MDS-UPDRS III) has 33 scores across 18 items (each score 0-4, range of total score 0-132, with higher scores indicating more severe motor symptoms) is completed by a trained rater during an examination of the patient, and is the most commonly-used assessment of parkinsonism in clinical trials. MDS-UPDRS III includes ratings for tremor, slowness (bradykinesia), stiffness (rigidity), and gait/balance. The MDS-UPDRS III will be administered to all participants (quetiapine or pimavanserin) at each in-person visit (baseline, 3 weeks, 5 weeks, and 8 weeks). Administration will also occur at weeks 10, 13, 15, and 18 for non-responders at week 8, and months 3, 6, 9, and 12 for responders at week 8. The CGI-I for parkinsonism will similarly be assessed at these study visits to address this secondary outcome.
  • Zarit Caregiver Burden Scale
    • Time Frame: 8 Weeks
    • The Zarit Burden Interview (ZBI) is a 22-item self-report inventory that examines burden associated with functional/behavioral impairments and the home care situation.64 It was originally developed to measure subjective burden among caregivers of adults with dementia. The items are worded subjectively, focusing on the affective response of the caregiver. Each question is scored on a 5-point Likert scale ranging from 0 to 4 (0-Never, 1-Rarely, 2-Sometimes, 3-Frequently, 4-Nearly always). The ZBI total score ranges from 0 (low burden) to 88 (high burden), the sum of the scores from all 22 questions. Interpretation of the total scores is typically: 1) 0-21 little or no burden; 2) 21-40 mild to moderate burden; 3) 41-60 moderate to severe burden; and 4) 61-88 severe burden. The ZBI will be administered to all participants’ informed other at baseline and treatment phase visits of Weeks 5 and 8.

Participating in This Clinical Trial

Inclusion Criteria

  • Veteran – Diagnosis of idiopathic PD for 2 or more years – Psychosis [with Neuropsychiatric Inventory (NPI) hallucinations (B) or delusions (A) score 4 or greater] – Stable dose of PD medications for at least 1 month 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 in-person contact with the patient (at least 5 days per week, and at least 4 hours per day that is spent with patient) English-speaking Exclusion Criteria:

  • Psychosis symptoms severe enough to preclude enrollment in a clinical trial and require prompt clinical care instead – Treatment with an antipsychotic, including pimavanserin in the past year, except quetiapine <50 mg/day which has been discontinued for at least 1 month prior to study enrollment – Deep brain stimulation (DBS) surgery occurring within 6 months prior or having unstable stimulator settings in the previous month – History of a psychotic disorder prior to PD, including schizophrenia and bipolar disorder – Suspected atypical parkinsonian disorder or dementia with Lewy bodies (DLB) – Psychosis secondary to other toxic or metabolic disorder – Congestive heart failure – History of stroke within the last 6 months – History of myocardial infarction within the last 6 months – History of long QT syndrome or prolonged QTc [>450ms in men, >470ms in women] at screening/baseline (or baseline, if applicable) – Current uncontrolled serious medical illness – Clinically significant hepatic impairment or severe renal impairment (eGFR <30 mL/min) – Currently taking medications that are significant CYP3A4 inhibitors or inducers – Comorbid medical condition determined too severe by SI to allow participation in clinical trial – Failure to tolerate quetiapine or pimavanserin previously – Moderate to severe PD dementia (MoCA score <13) – Currently enrolled in another therapeutic or interventional study – Nursing home placement at baseline or planned placement during the study – Active suicidality – Pregnancy/Pregnant, or a female of child-bearing potential who is unwilling to use a reliable form of contraception

Gender Eligibility: All

Minimum Age: 40 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • VA Office of Research and Development
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Daniel Weintraub, MD, Study Chair, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
  • Overall Contact(s)
    • Daniel Weintraub, MD, (215) 823-5800, daniel.weintraub@va.gov

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