Healthy Volunteers - Male and FemalePhase 1NCT07262736
Pharmacokinetics of Clozapine and Norclozapine and the Effect of Pantoprazole
A Phase 1 study testing clozapine and pantoprazole in people with Healthy Volunteers - Male and Female, run by Universiti Sains Malaysia at 1 site in Malaysia.
Trial summary
Clozapine is an effective treatment for patients with schizophrenia who do not respond to other therapies, but its blood concentration varies widely between individuals due to genetic and physiological differences. Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Volunteers - Male and Female
- What is being tested?
- clozapine and pantoprazole
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 33 participants
- Where
- 1 siteMalaysia
- Study dates
- 6 Feb 2021to 28 Feb 2022
- Phase
- Phase 1
- Are there results?
- None posted in the registry
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 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy adult volunteers aged 18 to 50 years
- No history of chronic medical or psychiatric disease, as confirmed by baseline medical evaluation, medical history, and electrocardiogram (ECG)
- No use of any medications for at least two weeks before study initiation
Who cannot join
- Pregnant or breastfeeding women
- Current smokers
Trial locations and contacts
1 site in 1 country.
About this study
Clozapine is an effective treatment for patients with schizophrenia who do not respond to other therapies, but its blood concentration varies widely between individuals due to genetic and physiological differences. Proton pump inhibitors such as pantoprazole are often prescribed in this population to prevent stomach discomfort, yet their impact on clozapine exposure has not been fully characterized. This clinical study will investigate the pharmacokinetics of clozapine and its main metabolite norclozapine, the influence of individual characteristics on drug exposure, and the effect of pantoprazole coadministration. Healthy adult volunteers will participate in a randomized open label cross over design, receiving a single dose of clozapine alone and again after pantoprazole treatment. Outcomes include clozapine and norclozapine plasma concentration time profiles, pharmacokinetic parameters, and safety assessments.
- Conditions
- Healthy Volunteers - Male and Female
- Being tested
- clozapine, pantoprazole
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
clozapineDrug
Single dose of 12.5 mg clozapine (half 25 mg tablet)
pantoprazoleDrug
Five daily doses of pantoprazole tablets 40 mg to be started four days prior to the clozapine administration
| Study group | Role | What they receive |
|---|---|---|
| Clozapine | Active comparator | Single dose of 12.5 mg clozapine Receives: Drug: clozapine |
| Clozapine and pantoprazole | Active comparator | Single dose of 12.5 mg clozapine after five daily doses of pantoprazole tablets 40 mg to be started four days prior to the clozapine administration Receives: Drug: clozapine; Drug: pantoprazole |
What is being measured
The primary outcome is the main question the study is designed to answer.
Peak Plasma Concentration (Cmax)
Maximum plasma concentration of clozapine following a single oral dose
Measured: From pre-dose to 8 hours after a single oral dose of clozapine
Area Under the Plasma Concentration-Time Curve (AUC)
AUC of clozapine plasma concentration from time zero to the last measurable concentration following a single oral dose
Measured: From pre-dose to 8 hours after dosing
Secondary outcomes (2)
Area Under the Concentration-Time Curve Extrapolated to Infinity (AUCinf)
Area under the plasma concentration-time curve from time zero extrapolated to infinity
Measured: From pre-dose to last measurable concentration
Time to Peak Concentration (Tmax)
Time to reach maximum observed plasma concentration of clozapine
Measured: From pre-dose to 8 hours after dosing
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Dec 2025
- Study start6 Feb 2021
- Primary completion28 Feb 2022
- Study completion28 Feb 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Healthy Volunteers - Male and FemaleStudies of the same condition, open and under way.
- 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 1
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 33 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universiti Sains Malaysia
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Orwa Albitar, Universiti Sains Malaysia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07262736
- Sponsor's protocol ID
- MY20090488
- Status last verified
- Nov 2025
- First submitted
- 19 Nov 2025
- Last updated
- 4 Dec 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The datasets generated during and analysed during the current study are available from the corresponding author on reasonable request.
Publications
Albitar O, Muda MR, Ghadzi SMS, Noor DAM, Ibrahim B, Teh CH, Akkaif MA, Aziz FA. Pharmacogenetics and pharmacometabolomics predictors of clozapine and norclozapine pharmacokinetic exposure in healthy volunteers. Eur J Clin Pharmacol. 2025 Oct;81(10):1429-1438. doi: 10.1007/s00228-025-03884-w. Epub 2025 Jul 22.
PubMed 40694104Albitar O, Harun SN, Sheikh Ghadzi SM. Semi-physiological Pharmacokinetic Model of Clozapine and Norclozapine in Healthy, Non-smoking Volunteers: The Impact of Race and Genetics. CNS Drugs. 2024 Jul;38(7):571-581. doi: 10.1007/s40263-024-01092-1. Epub 2024 Jun 5.
PubMed 38836990
Study at a glance
From the registry record, last updated by the sponsor on 4 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pharmacokinetics of Clozapine and Norclozapine and the Effect of Pantoprazole
- ClinicalTrials.gov ID
- NCT07262736
- Acronym / sponsor ID
- MY20090488
- Conditions
- Healthy Volunteers - Male and Female
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 33 participants (actual)
- Lead sponsor
- Universiti Sains MalaysiaUniversity, hospital or other
- Study start
- 6 Feb 2021 (actual)
- Primary completion
- 28 Feb 2022 (actual)
- Study completion
- 28 Feb 2022 (actual)
- First posted
- 4 Dec 2025 (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 an effective treatment for patients with schizophrenia who do not respond to other therapies, but its blood concentration varies widely between individuals due to genetic and physiological differences. Proton pump inhibitors such as pantoprazole are often prescribed in this population to prevent stomach discomfort, yet their impact on clozapine exposure has not been fully characterized. This clinical study will investigate the pharmacokinetics of clozapine and its main metabolite norclozapine, the influence of individual characteristics on drug exposure, and the effect of pantoprazole coadministration. Healthy adult volunteers will participate in a randomized open label cross over design, receiving a single dose of clozapine alone and again after pantoprazole treatment. Outcomes include clozapine and norclozapine plasma concentration time profiles, pharmacokinetic parameters, and safety assessments.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Clozapine | Active comparator | Drug: clozapineSingle dose of 12.5 mg clozapine |
| Clozapine and pantoprazole | Active comparator | Drug: clozapine, Drug: pantoprazoleSingle dose of 12.5 mg clozapine after five daily doses of pantoprazole tablets 40 mg to be started four days prior to the clozapine administration |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Healthy adult volunteers aged 18 to 50 years
- No history of chronic medical or psychiatric disease, as confirmed by baseline medical evaluation, medical history, and electrocardiogram (ECG)
- No use of any medications for at least two weeks before study initiation
Key exclusion criteria (2 listed)
- Pregnant or breastfeeding women
- Current smokers
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 |
|---|---|---|
| clozapineSingle dose of 12.5 mg clozapine (half 25 mg tablet) | Drug | Clozapine, Clozapine and pantoprazole |
| pantoprazoleFive daily doses of pantoprazole tablets 40 mg to be started four days prior to the clozapine administration | Drug | Clozapine and pantoprazole |
Primary outcome
Peak Plasma Concentration (Cmax)
Time frame: From pre-dose to 8 hours after a single oral dose of clozapine
Maximum plasma concentration of clozapine following a single oral dose
Area Under the Plasma Concentration-Time Curve (AUC)
Time frame: From pre-dose to 8 hours after dosing
AUC of clozapine plasma concentration from time zero to the last measurable concentration following a single oral dose
2 secondary outcomes
Area Under the Concentration-Time Curve Extrapolated to Infinity (AUCinf)
Time frame: From pre-dose to last measurable concentration
Time to Peak Concentration (Tmax)
Time frame: From pre-dose to 8 hours after dosing
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Dec 2025.
- Results publication: PubMed 40694104Albitar O, Muda MR, Ghadzi SMS, Noor DAM, Ibrahim B, Teh CH, Akkaif MA, Aziz FA. Pharmacogenetics and pharmacometabolomics predictors of clozapine and norclozapine pharmacokinetic exposure in healthy volunteers. Eur J Clin Pharmacol. 2025 Oct;81(10):1429-1438. doi: 10.1007/s00228-025-03884-w. Epub 2025 Jul 22.
- Results publication: PubMed 38836990Albitar O, Harun SN, Sheikh Ghadzi SM. Semi-physiological Pharmacokinetic Model of Clozapine and Norclozapine in Healthy, Non-smoking Volunteers: The Impact of Race and Genetics. CNS Drugs. 2024 Jul;38(7):571-581. doi: 10.1007/s40263-024-01092-1. Epub 2024 Jun 5.
- Individual participant dataSharing planned: Yes. The datasets generated during and analysed during the current study are available from the corresponding author on reasonable request.
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing clozapine and pantoprazole in people with Healthy Volunteers - Male and Female, run by Universiti Sains Malaysia at 1 site in Malaysia.
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 3 inclusion and 2 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: finished, as of the sponsor's last update on 4 Dec 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 Malaysia. 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 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Peak Plasma Concentration (Cmax) (time frame: From pre-dose to 8 hours after a single oral dose of clozapine). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07262736, which also lists 2 linked publications.
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 4 Dec 2025.