Investigating the effects of clozapine on immune function in Parkinson's disease

Assessment of Clozapine-related Immunodeficiency Effect in Parkinsons Disease Patients

PHASE4 · Centre Hospitalier Universitaire, Amiens · NCT06634641

This study tests how clozapine affects the immune system in people with Parkinson's disease who have psychotic symptoms, to see if it increases their risk of infections.

Quick facts

PhasePHASE4
Study typeInterventional
Enrollment24 (estimated)
Ages18 Years and up
SexAll
SponsorCentre Hospitalier Universitaire, Amiens (other)
Drugs / interventionschemotherapy
Locations1 site (Salouël)
Trial IDNCT06634641 on ClinicalTrials.gov

What this trial studies

This study examines the immunodeficiency effects associated with clozapine treatment in patients with Parkinson's disease experiencing psychotic symptoms. It involves regular monitoring of blood counts to assess the risk of neutropenia and potential infections due to clozapine. The study aims to understand the immunosuppressive effects of clozapine, which may resemble those seen in patients with common variable immunodeficiency. Participants will undergo blood tests weekly for the first 18 weeks and monthly thereafter to ensure safety during treatment.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with Parkinson's disease and psychotic symptoms that necessitate clozapine treatment.

Not a fit: Patients who have contraindications to clozapine or hypersensitivity to the drug will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved management strategies for patients with Parkinson's disease who require clozapine, enhancing their safety and treatment outcomes.

How similar studies have performed: While the immunodeficiency effects of clozapine have been noted, this specific investigation into its impact on Parkinson's disease is relatively novel and has not been extensively studied.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patient ≥ 18 years old with Parkinson's disease according to MDS 2015 criteria
* Psychotic symptoms requiring treatment with Clozapine
* Patients with initially a normal leukocyte count (number of white blood cells

  ≥ 3500/mm3 \[3.5 x 109/l\] and an absolute neutrophil count PNN ≥ 2000/mm3 \[2 x 109/l\])
* patients in whom the number of white blood cells (WBC) and the absolute number of neutrophils (PNN) may be determined regularly at the following intervals: once a week during the first 18 weeks of treatment and, thereafter, at least every 4 weeks for the duration of the treatment. This monitoring must be continued throughout the treatment and for 4 weeks who follow the complete cessation of CLOZAPINE
* Informed and written consent.
* Affiliation to a social security system

Exclusion Criteria:

* Patients with a contraindication to the use of Clozapine according to the summary of product characteristics (SPC)
* Hypersensitivity to the active substance or to any of the excipients.
* Patients who cannot receive regular blood tests.
* History of granulopenia or toxic or idiosyncratic agranulocytosis (unless it results from previous chemotherapy).
* History of agranulocytosis induced by CLOZAPINE
* Treatment with CLOZAPINE should not be started at the same time as substances known to have a high potential for inducing agranulocytosis; The concomitant administration of depot antipsychotics is not recommended.
* Functional bone marrow failure.
* Uncontrolled epilepsy.
* Alcoholic or induced psychosis, drug intoxication, comatose states.
* Circulatory collapse and / or CNS depression regardless of the aetiology.
* Severe renal or cardiac disorders (eg: myocarditis).
* Active liver disease with nausea, anorexia or jaundice; progressive liver disease, liver failure.
* Paralytic ileus.
* Patient with another potential cause of immunosuppression
* Immunosuppressive or immune modulatory treatment active or stopped for less than 5 years
* Anti-epileptic treatment active or stopped for less than 5 years
* Chemotherapy active or stopped for less than 5 years
* Solid or hematologic cancer active or treated for less than 5 years
* Human immunodeficiency virus infection
* Already known constitutional immune deficiency
* Nephrotic syndrome
* Protein-losing enteropathy
* A history of radiotherapy
* Long-term use of corticosteroids
* Patient with potentially major cognitive disorders defined by a MoCA score less than or equal to 23
* Pregnant or breastfeeding women
* Patient under guardianship/curatorship or deprived of liberty

Where this trial is running

Salouël

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.

View on ClinicalTrials.gov →

Conditions: Clozapine, Parkinson&#39, s Disease, Immunodeficiency, Psychosis, clozapine, parkinson&#39, s disease

Last reviewed 2026-05-15 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.