A Study of the Safety and Efficacy of Pimavanserin in Patients With Parkinson's Disease Psychosis

The purpose of this study is to evaluate the safety and efficacy of 34 mg pimavanserin compared to placebo in patients with Parkinson's disease psychosis (PDP).

Inclusion Criteria: 1. Male or female of 40 years of age or older; 2. A clinical diagnosis of Parkinson's disease with a minimum duration of 1 year; 3. Subjects must have had psychotic symptoms that developed after the diagnosis of Parkinson's disease was established. These symptoms must have included visual hallucinations and/or auditory hallucinations, and/or delusions； 4. Psychotic symptoms were to have been present for at least one month and the subject must have been actively experienced psychotic symptoms each week during the month prior to the Screening visit; 5. Symptoms severe enough to warrant treatment with an antipsychotic agent; documented at screening by items A and B of the NPI, and defined as a score of 4 or greater on either the Hallucinations (Frequency x Severity) or Delusions (Frequency x Severity) scales OR a total combined score of 6 or greater; 6. At the baseline visit, subject must have had a SAPS Hallucinations or Delusions global item (H7 or D13) score ≥3 AND a score \>3 on at least one other non-global item using the modified 9-item SAPS Hallucinations and Delusions domains; 7. Subject must have had a clear sensorium at study entry (i.e., oriented to time, person, and place); 8. Subject must have been on stable dose of anti-Parkinson's medication for 1 month prior to Day 1 (Baseline) and during the trial; 9. If a Subject had received stereotaxic surgery for sub-thalamic nucleus deep brain stimulation they must have been at least 6 months post-surgery and the stimulator settings must have been stable for at least 1 month prior to Day 1 (Baseline) and must remain stable during the trial; 10. Subjects of reproductive age (male/female) must have agreed to use a clinically acceptable method of contraception for at least one month prior to randomization, during the study, and one month following completion of the study; 11. The subject was required to be willing and able to provide consent; 12. Caregiver was required to be willing and able to provide consent and agrees to accompany the subject to all visits. Exclusion Criteria: 1. Subject with psychotic symptoms (hallucinations and delusions) which could be better explained as a part of a toxic, metabolic or infection-induced delirium /encephalopathy , psychosis due to substance abuse, psychosis associated with schizophrenia, bipolar disorder or psychotic depression; 2. Subject who was likely to have an allergy or sensitivity to pimavanserin based on known allergies to drugs of the same class; 3. Subject who had previously been randomized in any prior clinical study with pimavanserin, and/or received of any other investigational; 4. Subject with a history of significant psychotic disorders prior to or concomitantly with the diagnosis of Parkinson's disease including, but not limited to, schizophrenia or bipolar disorder; 5. Subjects had a significant risk of excitability or committing suicide based on the investigator's judgement; Any suicidal behavior in the year prior to or during screening; Subjects with a Columbia-Suicide Severity Rating Scale (C-SSRS) positive response to suicidal ideation items 4, or 5 are not eligible during the screening period. 6. Subject with atypical Parkinsonism (Parkinson's plus, MSA, PSP), or secondary parkinsonism variants such as tardive or medication induced parkinsonism; 7. Subject who had received previous ablative stereotaxic surgery (i.e., pallidotomy and thalamotomy) to treat Parkinson's disease; 8. Had a score on the Mini-Mental State Examination (MMSE) of \