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HealthyNCT01061112

Effects of Genotype on CYP2C9 Drug Interactions

An observational study of Healthy, run by University of Minnesota at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This research study will help determine how a person's genetic makeup affects their responses to drugs, the ability of the body to break down drugs, and their potential to experience an interaction between drugs. Read more about this study

Who is it for?
Ages 18 to 60 yearsHealthy volunteers can take part
Conditions the study is for
Healthy
What is being tested?
Flurbiprofen Inhibition - Flurbiprofen & Fluconazole and Ketoprofen Inhibition - Ketoprofen & Fluconazole
How many people
23 participants
Where
1 siteUnited States
Study dates
Dec 2009to Jun 2014
Phase
Observational
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 60 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Study population: Subjects are selected from a pharmacogenetics registry in which their drug metabolism genotype has been determined.

Who may be able to join

  • Subjects will be 18-60 years old.
  • Women of child-bearing age must be willing to use measures to avoid conception during the study period.
  • Subjects must agree not to take any known substrates, inhibitors, inducers, or activators of CYP2C9.

Who cannot join

  • Current cigarette smoker.
  • Abnormal renal or liver function tests, physical exam, or recent history of hepatic, renal, gastrointestinal or neoplastic disease.
  • Allergy to tolbutamide, flurbiprofen, ketoprofen, fluconazole or phenytoin and other chemically related drugs.
  • Recent ingestion (< 1 week) of any medication known to be metabolized by or alter activity of CYP2C9.
  • A positive pregnancy test during the time of the pharmacokinetic study.

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Clinical and Translational Science Institute

    Minneapolis, Minnesota, 55414

Other trials in United States

About this study

This research study will help determine how a person's genetic makeup affects their responses to drugs, the ability of the body to break down drugs, and their potential to experience an interaction between drugs. We are investigating the drug interactions between an antifungal drug called fluconazole and the commonly used drugs tolbutamide, flurbiprofen, and ketoprofen. Tolbutamide is used for management of Type 2 diabetes. Both flurbiprofen and ketoprofen are non-steroidal anti-inflammatory drugs (NSAIDs) often used for arthritis or pain. We are interested in studying whether individuals with certain genetic profiles have different drug interactions than normal. This research is being done to see if certain genetic profiles require us to adjust medication doses differently than is needed for the general population. Genetic profiles of subjects are determined from their previous participation in the Pharmacogenetics Registry (Investigator Richard Brundage, University of Minnesota).

The study hypothesis is: Fraction metabolized by CYP2C9 enzyme determines the extent of drug interactions in CYP2C9*1/*1 individuals but this factor (fraction metabolized) becomes less influential and drug interactions are attenuated in a gene-dose dependent manner in individuals with one or more defective alleles.

Read the detailed description

The study hypothesis is: Fraction metabolized by CYP2C9 enzyme determines the extent of drug interactions in CYP2C9*1/*1 individuals but this factor (fraction metabolized) becomes less influential and drug interactions are attenuated in a gene-dose dependent manner in individuals with one or more defective alleles.

Objective: Examine the extent of fluconazole inhibition of drugs with varying degrees of fraction metabolized by CYP2C9 in individuals with the CYP2C9*1/*1, CYP2C9*1/*3 and CYP2C9*3/*3 genotypes.

People differ in their genetic makeup. This includes differences in genes involved in drug metabolism, transport, and effect in the body. People with certain genetic profiles produce altered enzymes, transporters, and receptors that may respond in different ways to drugs. Altered enzymes cause some drugs to be broken down at a different rate than normal. As a result, drug concentrations build up in the blood, and increase the risk of side effects. Furthermore, when two drugs are taken together, the possibility exists for the drugs to interact, with one drug causing a change in the metabolism of the other or both of the drugs. It is not known whether people with an altered genetic makeup also have an altered experience with drug interactions. Altered drug transporters can affect the absorption and elimination of drugs as compared to normal causing differences in how long the drug stays in the body. Finally, altered drug receptors can respond differently to drugs and, thus, produce altered desired or undesired effects.

In this study, we will be investigating the drug interactions between an antifungal drug called fluconazole and the commonly used drugs tolbutamide, flurbiprofen, and ketoprofen in subjects with three different genotypes of the CYP2C9 enzyme. Tolbutamide is used for management of Type 2 diabetes. Both flurbiprofen and ketoprofen are non-steroidal anti-inflammatory drugs (NSAIDs) often used for arthritis or pain. We are interested in studying whether individuals with certain genetic profiles have different drug interactions than normal. This research is being done to see if certain genetic profiles require us to adjust medication doses differently than is needed for the general population.

The cytochrome P450 (CYP) superfamily of enzymes plays an important role in the oxidative conversion of numerous xenobiotics into their more hydrophilic metabolites. CYP2C9, is an important member of the CYP superfamily, accounting for 10-20% of the CYP protein content in human liver and catalyzes approximately 20% of the CYP mediated drug oxidation reactions, including tolbutamide and the non-steroidal anti-inflammatory drugs (NSAIDs) such as ketoprofen and flurbiprofen. It is now well established that genetic factors play an important role in the control of CYP2C9 expression and activity. In particular, the *3 allele is expressed at an allele frequency of 15%. Homozygotic *3 individuals exhibit significantly reduced oral clearance for several CYP2C9 substrates. In most of these cases, the reduction in clearance approaches 80% and even in heterozygotic individuals, this reduction in clearance is 40-50% due to the co-dominant expression of CYP2C9. This reduction in clearance has been associated with an increased frequency of adverse events following warfarin or phenytoin administration, two clinically important drugs that exhibit a narrow therapeutic index. The therapeutic index is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxic effects.

Conditions
Healthy
Being tested
Flurbiprofen Control - Flurbiprofen Only, Flurbiprofen Inhibition - Flurbiprofen & Fluconazole, Ketoprofen Control - Ketoprofen Only, Ketoprofen Inhibition - Ketoprofen & Fluconazole, Tolbutamide Control - Tolbutamide Only
Keywords
Drug Interactions, Genetics, CYP2C9, Healthy Volunteers

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Flurbiprofen Control - Flurbiprofen OnlyDrug

    Also called Ansaid

    A single 50 mg flurbiprofen dose taken at the start of the study period. No other drugs administered during this study period.

  • Flurbiprofen Inhibition - Flurbiprofen & FluconazoleDrug

    Also called Ansaid, Diflucan

    A single 50 mg flurbiprofen dose taken at the start of the study period. 400 mg fluconazole taken every morning starting a week before the start of the study period and continuing throughout the study period.

  • Ketoprofen Control - Ketoprofen OnlyDrug

    Also called Orudis

    A single 75 mg ketoprofen dose taken at the start of the study period. No other drugs administered during this study period.

  • Ketoprofen Inhibition - Ketoprofen & FluconazoleDrug

    Also called Orudis, Diflucan

    A single 75 mg ketoprofen dose taken at the start of the study period. 400 mg fluconazole taken every morning starting a week before the start of the study period and continuing throughout the study period.

  • Tolbutamide Control - Tolbutamide OnlyDrug

    Also called Orinase

    A single 500 mg tolbutamide dose taken at the start of the study period. No other drugs administered during this study period.

  • Tolbutamide Inhibition - Tolbutamide & FluconazoleDrug

    Also called Orinase, Diflucan

    A single 500 mg tolbutamide dose taken at the start of the study period. 400 mg fluconazole taken every morning starting a week before the start of the study period and continuing throughout the study period.

Study groups in NCT01061112
Study groupRoleWhat they receive
CYP2C9*1/*1 GenotypeThis genotype is considered the wild type genotype. Individuals with the CYP2C9*1/*1 genotype have two *1 alleles and participated in the following interventions: Flurbiprofen Control - Flurbiprofen Only, Flurbiprofen Inhibition - Flurbiprofen \& Fluconazole, Ketoprofen Control - Ketoprofen Only, Ketoprofen Inhibition - Ketoprofen \& Fluconazole, Tolbutamide Control - Tolbutamide Only, and Tolbutamide Inhibition - Tolbutamide \& Fluconazole.
Receives: Drug: Flurbiprofen Control - Flurbiprofen Only; Drug: Flurbiprofen Inhibition - Flurbiprofen & Fluconazole; Drug: Ketoprofen Control - Ketoprofen Only; Drug: Ketoprofen Inhibition - Ketoprofen & Fluconazole; Drug: Tolbutamide Control - Tolbutamide Only; Drug: Tolbutamide Inhibition - Tolbutamide & Fluconazole
CYP2C9*1/*3 GenotypeIndividuals with the CYP2C9*1/*3 genotype have one *1 allele and one *3 allele and participated in the following interventions: Flurbiprofen Control - Flurbiprofen Only, Flurbiprofen Inhibition - Flurbiprofen \& Fluconazole, Ketoprofen Control - Ketoprofen Only, Ketoprofen Inhibition - Ketoprofen \& Fluconazole, Tolbutamide Control - Tolbutamide Only, and Tolbutamide Inhibition - Tolbutamide \& Fluconazole.
Receives: Drug: Flurbiprofen Control - Flurbiprofen Only; Drug: Flurbiprofen Inhibition - Flurbiprofen & Fluconazole; Drug: Ketoprofen Control - Ketoprofen Only; Drug: Ketoprofen Inhibition - Ketoprofen & Fluconazole; Drug: Tolbutamide Control - Tolbutamide Only; Drug: Tolbutamide Inhibition - Tolbutamide & Fluconazole
CYP2C9*3/*3 GenotypeIndividuals with the CYP2C9*3/*3 genotype have two *3 alleles and participated in the following interventions: Flurbiprofen Control - Flurbiprofen Only, Flurbiprofen Inhibition - Flurbiprofen \& Fluconazole, Ketoprofen Control - Ketoprofen Only, Ketoprofen Inhibition - Ketoprofen \& Fluconazole, Tolbutamide Control - Tolbutamide Only, and Tolbutamide Inhibition - Tolbutamide \& Fluconazole.
Receives: Drug: Flurbiprofen Control - Flurbiprofen Only; Drug: Flurbiprofen Inhibition - Flurbiprofen & Fluconazole; Drug: Ketoprofen Control - Ketoprofen Only; Drug: Ketoprofen Inhibition - Ketoprofen & Fluconazole; Drug: Tolbutamide Control - Tolbutamide Only; Drug: Tolbutamide Inhibition - Tolbutamide & Fluconazole

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Flurbiprofen Clearance

    Measure of blood concentrations of Flurbiprofen 48 hours post Flurbiprofen dose

    Measured: 48 hours post Flurbiprofen dose

  2. Ketoprofen Clearance

    Measure of blood concentrations of Ketoprofen 48 hours post Ketoprofen dose

    Measured: 48 hours post Ketoprofen dose

  3. Tolbutamide Clearance

    Measure of blood concentrations of Tolbutamide 48 hours post Tolbutamide dose

    Measured: 48 hours post Tolbutamide dose

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted2 Feb 2010 (estimated)
  2. Study startDec 2009
  3. Primary completionJun 2014
  4. Study completionJun 2014

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
23 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT01061112
Sponsor's protocol ID
0812M56082
Other IDs
R01GM069753
Status last verified
Jul 2019
First submitted
29 Jan 2010
Last updated
18 Jul 2019
Results posted
No
Data monitoring committee
No

Questions about this trial

What is this clinical trial studying?

An observational study of Healthy, run by University of Minnesota at 1 site in United States.

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 5 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 18 Jul 2019. 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 United States. 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.

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?

Flurbiprofen Clearance (time frame: 48 hours post Flurbiprofen dose). The study lists 3 primary outcomes in all. 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 18 Jul 2019.

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