NCT04580134 · University of Texas Southwestern Medical Center
CLOZAPINE Response in Biotype-1
What this study is about
The CLOZAPINE study is designed as a multisite study across 5 sites and is a clinical trial, involving human participants who are prospectively assigned to an intervention. The study will utilize a stringent randomly assigned, double-blinded, parallel group clinical trial design. B2 group will serve as psychosis control with risperidone as medication control.
View original scientific description
The CLOZAPINE study is designed as a multisite study across 5 sites and is a clinical trial, involving human participants who are prospectively assigned to an intervention. The study will utilize a stringent randomized, double-blinded, parallel group clinical trial design. B2 group will serve as psychosis control with risperidone as medication control. The study is designed to evaluate effect of clozapine on the B1 participants, and the effect that will be evaluated is a biomedical outcome.
Interventions
DRUG
clozapine
Biotype 1 and Biotype 2
DRUG
risperidone
Biotype 1 and Biotype 2
Primary outcome measures
Change in the PANSS total score
Time frame: Week 4, Week 10 and Week 18
The change in the PANSS total score from the clinical trial baseline (W4) to the end of treatment (W18) will be a primary outcome measure. We predict that B1/clozapine will show a significantly larger change in the PANSS score from W4 to W18, compared to B1/risperidone, B2/clozapine and B2/risperidone. We will also examine the patterns of change in the PANSS score during the 'stable treatment' phase (W10-W18), across the same study groups. A mixed-effect repeated-measures ANCOVA \[2(Biotypes) × 2(clozapine/risperidone) × 2(time points\] will be used. We also predict that the reduction in the PANSS scores will correlate with increased IEA in B1/clozapine but not in B1/risperidone, B2/clozapine or B2/risperidone. Multivariate prediction models will be used.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 18-60y/o; males and females; all races and ethnicities; able to provide written informed consent; able to read, speak, and understand English; medically stable; meeting DSM-IV (SCID-based) criteria for schizophrenia, schizoaffective disorder, or bipolar I disorder with psychotic features (we will use DSM-IV to be consistent with prior B-SNIP samples); PANSS total score of ≥70 and at least one item scored ≥5 or two items scored ≥4 on PANSS Positive Subscale; normal baseline values for absolute neutrophil count (ANC above 1500/mm3)
Exclusion criteria
- premorbid intellectual ability estimate below 70 (WRAT-4, Word Reading subtest, age-corrected standardized score); comorbid DSM-IV diagnosis of alcohol or substance abuse in prior 1 month or substance dependence in prior 3 months; neurological (e.g., seizure disorder, stroke, traumatic brain injury with a loss of consciousness ≥ 30min) or severe medical condition (e.g., decompensated cardiovascular disorder, AIDS) that may affect central nervous system function; concomitant medications known to affect EEG properties (i.e., lithium, anticonvulsants, benzodiazepines) or strong CYP 1A2 inhibitors (e.g., ciprofloxacin, enoxacin) or strong CYP 3A4 inducers (e.g., phenytoin, carbamazepine, phenobarbital, rifampin) which cannot be safely discontinued; vulnerable populations (e.g., pregnant, nursing, incarcerated); unwilling to use reliable means of contraception; history of neuroleptic malignant syndrome; prior treatment with clozapine, prior treatment with long-acting injectable antipsychotics that are 1-month formulations within the past 3 months and for 3-month formulations within the past 6 months; intolerable side effects to either clozapine or risperidone in lifetime, or a previously failed trial of either clozapine or risperidone at adequate doses in lifetime; history of drug reaction with eosinophilia and systemic symptoms syndrome (DRESS), also known as drug-induced hypersensitivity syndrome (DIHS); high risk for suicide defined as more than 1 attempt in past 12 months that required medical attention, any attempt in the past 3 months or current suicidal ideation with plan and intent such that outpatient care is precluded; current homicidal ideation with plan and intent such that outpatient care is precluded.
Where
- Hartford, Connecticut
- Athens, Georgia
- Chicago, Illinois
- Boston, Massachusetts
- Dallas, Texas
Collaborators
National Institute of Mental Health (NIMH), Beth Israel Deaconess Medical Center, Hartford Hospital, University of Georgia, University of Chicago
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 11, 2026 · Source of record for eligibility and locations