ClozapinePhase 4CLOZIDPDNCT06634641
Clozapine-related Immunodeficiency in Parkinsons Disease
A Phase 4 study testing blood test in people with Clozapine and Parkinson's Disease (PD), run by Centre Hospitalier Universitaire, Amiens at 1 site in France.
Trial summary
Clozapine is a second generation antipsychotic drug used in psychiatry to treat schizophrenia, affective disorders or certain symptoms of dementia. In neurology, clozapine is frequently used and recommended to manage symptoms of psychosis associated with Parkinson's disease (PD). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Clozapine, Parkinson's Disease (PD), Immunodeficiency
- What is being tested?
- blood test
- How many people
- 24 participants
- Where
- 1 siteFrance
- Study dates
- 1 Oct 2024to Sep 2027
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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.
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- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
France1 site, 1 recruiting
- Recruiting
CHU Amiens-Picardie
Salouël, 80480
Mickaël AUBIGNAT, MD, 33 + 03 22 66 82 40, aubignat.mickael@chu-amiens.fr
About this study
Official title: Assessment of Clozapine-related Immunodeficiency Effect in Parkinsons Disease Patients
Clozapine is a second generation antipsychotic drug used in psychiatry to treat schizophrenia, affective disorders or certain symptoms of dementia. In neurology, clozapine is frequently used and recommended to manage symptoms of psychosis associated with Parkinson's disease (PD). The risk of neutropenia or agranulocytosis associated with clozapine estimated at 1.3% is well known to doctors around the world with a peak at one month and a decrease in risk after more than a year of treatment. This risk has led to the policy of "no blood, no drugs" and monitoring of the complete blood count (CBC) weekly for 18 weeks and then monthly for the duration of treatment.
Some studies suggest an increased risk of infections related to immunodeficiency induced by clozapine itself. This clozapine-induced immunodeficiency would be comparable to that encountered in patients with common variable immunodeficiency or under immunosuppressive treatment. In addition, this immunosuppressive effect linked to clozapine would not be dose dependent but time dependent. However, the only studies currently performed have been in psychiatric patients treated for schizophrenia.
It seems important to specifically explore clozapine-related immunodeficiency in PD patients treated with clozapine for PD-related psychosis. In this study, the investigators propose to evaluate the variations in serum immunoglobulin levels and lymphocyte subpopulations (B, T, NK) in parkinsonian patients treated with Clozapine at 6 months and 1 year after initiation of treatment.
- Conditions
- Clozapine, Parkinson's Disease (PD), Immunodeficiency, Psychosis
- Being tested
- blood test
- Keywords
- clozapine, parkinson's disease, immunodeficiency, psychosis
- Medical subject headings
- Immunologic Deficiency Syndromes, Psychotic Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
blood testBiological
Only carrying out additional immunological assays during blood tests before initiation of treatment, six months after initiation of treatment and then one year after initiation of treatment.
What is being measured
The primary outcome is the main question the study is designed to answer.
change in serum IgG levels
change in serum IgG levels after 6 months of clozapine treatment
Measured: 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Oct 2024
- Study start1 Oct 2024
- Primary completionSep 2027 (estimated)
- Study completionSep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ClozapineStudies of the same condition, open and under way.
- More trials run by Centre Hospitalier Universitaire, AmiensThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Centre Hospitalier Universitaire, Amiens
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06634641
- Sponsor's protocol ID
- PI2024_843_0069
- Acronym
- CLOZIDPD
- Status last verified
- Nov 2025
- First submitted
- 8 Oct 2024
- Last updated
- 19 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assessment of Clozapine-related Immunodeficiency Effect in Parkinsons Disease Patients
- ClinicalTrials.gov ID
- NCT06634641
- Acronym / sponsor ID
- CLOZIDPD / PI2024_843_0069
- Conditions
- Clozapine, Parkinson's Disease (PD), Immunodeficiency, Psychosis
- Keywords
- clozapine, parkinson's disease, immunodeficiency, psychosis
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- Centre Hospitalier Universitaire, AmiensUniversity, hospital or other
- Study start
- 1 Oct 2024 (actual)
- Primary completion
- Sep 2027 (estimated)
- Study completion
- Sep 2027 (estimated)
- First posted
- 10 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Clozapine is a second generation antipsychotic drug used in psychiatry to treat schizophrenia, affective disorders or certain symptoms of dementia. In neurology, clozapine is frequently used and recommended to manage symptoms of psychosis associated with Parkinson's disease (PD). The risk of neutropenia or agranulocytosis associated with clozapine estimated at 1.3% is well known to doctors around the world with a peak at one month and a decrease in risk after more than a year of treatment. This risk has led to the policy of "no blood, no drugs" and monitoring of the complete blood count (CBC) weekly for 18 weeks and then monthly for the duration of treatment.
Some studies suggest an increased risk of infections related to immunodeficiency induced by clozapine itself. This clozapine-induced immunodeficiency would be comparable to that encountered in patients with common variable immunodeficiency or under immunosuppressive treatment. In addition, this immunosuppressive effect linked to clozapine would not be dose dependent but time dependent. However, the only studies currently performed have been in psychiatric patients treated for schizophrenia.
It seems important to specifically explore clozapine-related immunodeficiency in PD patients treated with clozapine for PD-related psychosis. In this study, the investigators propose to evaluate the variations in serum immunoglobulin levels and lymphocyte subpopulations (B, T, NK) in parkinsonian patients treated with Clozapine at 6 months and 1 year after initiation of treatment.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- 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
Key exclusion criteria (27 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| blood testOnly carrying out additional immunological assays during blood tests before initiation of treatment, six months after initiation of treatment and then one year after initiation of treatment. | Biological | – |
Primary outcome
change in serum IgG levels
Time frame: 6 months
change in serum IgG levels after 6 months of clozapine treatment
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Nov 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing blood test in people with Clozapine and Parkinson's Disease (PD), run by Centre Hospitalier Universitaire, Amiens at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 27 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 19 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Mickaël AUBIGNAT, MD (33 + 03 22 66 82 40, aubignat.mickael@chu-amiens.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
change in serum IgG levels (time frame: 6 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Nov 2025.