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Relationship Between Neurotransmitter Receptor Polymorphisms, Plasma Concentrations and Clinical Response to Clozapine

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ClinicalTrials.gov Identifier: NCT00581932
Recruitment Status : Completed
First Posted : December 28, 2007
Last Update Posted : May 12, 2017
Information provided by (Responsible Party):

Study Description
Brief Summary:
This is a study designed to identify genetic polymorphisms (also called allelic variants or genetic markers) that are associated with response to clozapine. This information will be used to enhance the understanding of clozapine response and side effects. DNA from patients will be examined for significant associations between allelic variants in candidate genes in relation to clozapine effects on positive and negative symptoms, global response, quality of life, relapse rates and side effects.

Condition or disease

Detailed Description:
Patients age 18-65 with a DSM IV diagnosis of schizophrenia who have a history of nonresponse to conventional atypical antipsychotics and who are to be treated with clozapine by their psychiatrist, will be asked to participate at or near the time clozapine therapy is initiated. The Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Negative Symptoms (SANS), and the Scale for the Assessment of Positive Symptoms (SAPS) will be performed on all subjects at entry into the study, at 3 weeks, 5 weeks, 8 weeks, and at 4 and 6 months. Adverse effects will be monitored with the Simpson-Angus Scale, Barnes Akathisia scale and the AIMS at each of these time points. The Calgary Depression Scale will also be administered at each visit. A complete neurocognitive assessment battery will be completed at entry and at 6 months for those subjects willing to undergo neurocognitive testing. It is anticipated not all subjects will complete neurocognitive testing. A blood or cheek swab sample will be collected at study entry for DNA analysis. Plasma blood levels will be collected at weeks 3, 5, 8 and study completion for measurement of clozapine plasma concentrations. The subject's weight, BMI, smoking status and concomitant medications will be recorded at each visit.

Study Design

Study Type : Observational
Actual Enrollment : 76 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Relationship Between Neurotransmitter Receptor Polymorphisms, Plasma Concentrations and Clinical Response to Clozapine
Study Start Date : October 2001
Primary Completion Date : December 2015
Study Completion Date : December 2015

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Schizophrenia
Drug Information available for: Clozapine
U.S. FDA Resources

Groups and Cohorts

One group, all subjects with DSM-IV diagnosis of Schizophrenia, age 18-65 who are initiating clozapine therapy.

Outcome Measures

Primary Outcome Measures :
  1. Brief Psychiatric Rating Scale [ Time Frame: entry, 3 wks, 5 wks, 8 wks, 4 mo, 6 mo ]

Secondary Outcome Measures :
  1. Scale for the Assessment of Positive Symptoms [ Time Frame: entry, wk 3, wk 5, wk 8, 4 mo, 6 mo ]
  2. Scale for the assessment of Negative symptoms [ Time Frame: entry, 3 wk, 5 wk, 8 wk, 4 mo, 6 mo ]
  3. Calgary Depression Scale [ Time Frame: entry, 3 wk, 5 wk, 8 wk, 4 mo, 6 mo ]
  4. Abnormal Involuntary Movement Scale [ Time Frame: entry, 3 wk, 5 wk, 8 wk, 4 mo, 6 mo ]
  5. Barnes Akathisia Scale [ Time Frame: entry, 3 wk, 5 wk, 8 wk, 4 mo, 6 mo ]

Biospecimen Retention:   Samples With DNA
whole blood, saliva

Eligibility Criteria

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Psychiatric clinic, Inpatient Psychiatry unit

Inclusion Criteria:

  • Diagnosis of schizophrenia
  • Beginning clozapine therapy
  • age 18-65
  • must be willing to participate in interviews and provide a DNA sample

Exclusion Criteria:

  • no longer taking clozapine
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00581932

United States, Iowa
University of Iowa Hospitals and Clinics
Iowa City, Iowa, United States, 52242
Sponsors and Collaborators
Delwyn D. Miller
Principal Investigator: Del D Miller, PharmD, M.D. The University of Iowa
More Information

Responsible Party: Delwyn D. Miller, Professor, University of Iowa
ClinicalTrials.gov Identifier: NCT00581932     History of Changes
Other Study ID Numbers: 199901018
First Posted: December 28, 2007    Key Record Dates
Last Update Posted: May 12, 2017
Last Verified: May 2017

Keywords provided by Delwyn D. Miller, University of Iowa:
clozapine, schizophrenia

Additional relevant MeSH terms:
Schizophrenia Spectrum and Other Psychotic Disorders
Mental Disorders
Neurotransmitter Agents
Serotonin Antagonists
Serotonin Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Antipsychotic Agents
Tranquilizing Agents
Central Nervous System Depressants
Psychotropic Drugs
GABA Antagonists
GABA Agents