Longitudinal PET Imaging of Antipsychotic Binding to the Dopamine-3 Receptor in Schizophrenia (NCT07715253) | Clinical Trial Compass
Not Yet RecruitingPhase 1
Longitudinal PET Imaging of Antipsychotic Binding to the Dopamine-3 Receptor in Schizophrenia
100 participantsStarted 2026-12-01
Plain-language summary
This is a clinical trial in which 40 participants with schizophrenia will be randomized to 15 days of treatment with cariprazine (CAR) or brexpiprazole (BREX) in a single-blind manner. \[11C\]PHNO PET scans will be obtained before treatment and after 1 day and 15 days of treatment to examine the effects of antipsychotic medications on the dopamine-3 receptor (D3R). The overall objectives of the current study are to: 1) measure the acute binding of CAR/BREX to the D3R; 2) measure D3R availability for evidence of upregulation following subchronic administration of CAR/BREX in the same set of patients; 3) examine relationships between subchronic binding of CAR/BREX to, and upregulation of, the D3R vs. D2R and changes in positive symptoms, negative symptoms, and cognitive deficits. Relationships between subchronic binding of CAR/BREX and EPS will be explored.
Who can participate
Age range
18 Years – 55 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Individuals, any gender or sex, aged 18 to 55, inclusive at screen
. Capable of understanding the study procedures and able to provide informed consent
. Diagnosed with schizophrenia, schizoaffective, or schizophreniform disorder
. Negative urine toxicology
. Antipsychotic free (by choice and for reasons unrelated to the study), and for at least 3 weeks (4 for aripiprazole or LAIs) at the time of the baseline PET scan, inclusive of any antipsychotic-free time prior to consent. \[Any patient who requires inpatient hospitalization or acute medication treatment for clinical stabilization during the medication free period will not be included in this study; any participant who in the clinical judgment of the PIs or any involved clinician is not stable or appropriate for a medication free period will not be included.\]
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Acute D2 and D3 Receptor Occupancy
Timeframe: Day 1
2
Upregulation of D3 receptor following subchronic administration of antipsychotics
. Diagnosis of substance use disorder within the previous month
. A history of poor or inadequate response or hypersensitivity to CAR or BREX for any reason
. EKG abnormality that is clinically significant including a QTc interval \> 450 msec for men and \> 470 msec for women,
. Pregnant or breast-feeding women. Women of child-bearing potential must have a negative serum β-hCG pregnancy test at Visit 1, must have been using an acceptable method of contraception for 30 days before the study (i.e., before the first PET or MRI scan, whichever comes first), and must agree to do so for the whole study and 30 days after (unless post-menopausal or surgically sterile)
. Any clinically significant or unstable medical/neurological illness, condition, or disorder that is anticipated to potentially compromise participant safety on study medication
. Any material in the body that is a contraindication for MRI procedures or participated in prior nuclear medicine procedures in the past year that exceed FDA-defined limits when combined with radiation dosimetry from PET scanning in this protocol to avoid exceeding annual dosimetry limits (metal screener repeated before MRI scan). Individuals exposed to radiation in the workplace in the previous year will be excluded.
. Acute risk for suicide (i.e., score of 4-5 within the previous month or 6 within the previous 3 months on the CSSRS) or violence/homicide (e.g., homicidal ideation), or history of severe violent behavior or behavioral dyscontrol while antipsychotic-free
. A history of treatment resistance to antipsychotics or who have a duration of illness of greater than 20 years