Pimavanserin vs. Quetiapine for Treatment of Parkinson's Psychosis

DRUG

Pimavanserin

Fixed-dose 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. It is the only FDA-approved medication for PDP, but is still not the first-line AP used in PD. All participants assigned to pimavanserin will receive the FDA-approved dose of 34 mg (equivalent to 40 mg pimavanserin tartrate) daily without titration up or down; however, because pimavanserin is blinded to quetiapine, participants will undergo sham titration based on tolerability (i.e., overall adverse event profile) and efficacy (i.e., improvement in severity of psychosis).

DRUG

Quetiapine

Flexible-dose Quetiapine - Quetiapine, which is a mixed serotonin and dopamine receptor antagonist, is by far the most commonly used AP for PDP. However, scientific evidence for the efficacy of quetiapine in PDP is almost non-existent as most of the studies were underpowered, had high drop-out rates, and possibly underdosed quetiapine. Quetiapine immediate and extended release will be titrated as shown: Baseline visit Quetiapine: 25 mg IR QHS, All participants must be up-titrated to 50 mg/day Week 1 call Quetiapine: 50 mg XR QHS, Up-titration to 50 mg Week 3 visit Quetiapine: 100 mg XR QHS, Up-titration as appropriate Week 5 visit Quetiapine: 150 mg XR QHS, Up- or down-titration as appropriate Week 6 call Quetiapine: 200 mg XR QHS, Up- or down-titration as appropriate

CGI-I Psychosis

Time frame: 8 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.

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.