Comparing two medications for treating psychosis in Parkinson's disease and dementia with Lewy bodies

A Pragmatic Randomized Trial Comparing Antipsychotics in Lewy Body Disease

Phase 4 Interventional The University of Texas Health Science Center at San Antonio · NCT05590637

This study is testing which of two medications, pimavanserin or quetiapine, works better to help people with psychosis caused by Parkinson's disease or dementia with Lewy bodies.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment94 (estimated)
SexAll
SponsorThe University of Texas Health Science Center at San Antonio Academic / other
Locations2 sites (San Antonio, Texas and 1 other locations)
Trial IDNCT05590637 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to compare the effectiveness of two antipsychotic medications, pimavanserin and quetiapine, in treating psychosis associated with Parkinson's disease and dementia with Lewy bodies. Patients diagnosed with psychosis due to these conditions will be randomly assigned to receive either medication, and their improvement in symptoms will be assessed over a six-month period. The study seeks to provide clarity on which medication may offer better outcomes in a routine clinical setting. By focusing on real-world treatment scenarios, the trial aims to enhance understanding of psychosis management in Lewy body disease.

Who should consider this trial

Good fit: Ideal candidates for this study are patients diagnosed with psychosis due to Parkinson's disease or dementia with Lewy bodies who require initiation of an antipsychotic medication.

Not a fit: Patients who are currently taking an antipsychotic medication or have medical contraindications to either pimavanserin or quetiapine may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to more effective treatment options for patients experiencing psychosis due to Parkinson's disease or dementia with Lewy bodies.

How similar studies have performed: While there have been few comparison studies between these two medications, this trial aims to fill a gap in the existing literature, making it a novel approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients seen in the neurology clinic at UT Health San Antonio
* Diagnosed with psychosis due to PD or DLB
* Requiring initiation of an antipsychotic medication
* Clinical equipoise between quetiapine and pimavanserin must exist
* The prescribing provider must be comfortable prescribing and managing both quetiapine and pimavanserin

Exclusion Criteria:

* Medical contraindication to either medication
* Caregiver unavailable to complete NPI-Q
* Currently taking an antipsychotic medication
* Prescribing provider unwilling to manage either medication

Where this trial is running

San Antonio, Texas and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Parkinson's Disease PsychosisDementia With Lewy Bodiesquetiapinepimavanserinpsychosishallucinationsdelusions
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.