Effects of CYP2B6 Genetic Polymorphisms on Efavirenz Pharmacokinetics
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ClinicalTrials.gov Identifier: NCT00668395 |
Recruitment Status :
Completed
First Posted : April 29, 2008
Results First Posted : September 26, 2014
Last Update Posted : September 26, 2014
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- To see how the liver breaks down efavirenz by an enzyme called CYP2B6. It is suggested that when Efavirenz is taken repeatedly it may increase the amount of CYP2B6 in your liver and thus speed up your liver's ability to get rid of efavirenz from your body. This may render efavirenz and other medications ineffective.
- To see how efavirenz interact with other drugs taken at the same time with it.
- To see if genetic differences can change the way how the liver breaks down efavirenz and its interactions with other co-administered drugs.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
HIV | Drug: Efavirenz | Not Applicable |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 73 participants |
Allocation: | Non-Randomized |
Intervention Model: | Single Group Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Basic Science |
Official Title: | Effects of CYP2B6 Genetic Polymorphisms on Efavirenz Pharmacokinetics, Autoinduction and Drug Interactions in Healthy Volunteers. |
Study Start Date : | May 2007 |
Actual Primary Completion Date : | April 2010 |
Actual Study Completion Date : | April 2010 |

Arm | Intervention/treatment |
---|---|
CYP2B6*1/*1 genotype
Efavirenz clearance in this genotype was compared with the other genotypes
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Drug: Efavirenz
The metabolism and pharmacokinetics of efavirenz were assessed at a single 600 mg oral dose of efavirenz and after subjects took multiple doses of efavirenz (600 mg/day orally for 17 days).
Other Name: Sustiva |
CYP2B6*1/*6
Efavirenz clearance in this genotype was compared with the other genotypes
|
Drug: Efavirenz
The metabolism and pharmacokinetics of efavirenz were assessed at a single 600 mg oral dose of efavirenz and after subjects took multiple doses of efavirenz (600 mg/day orally for 17 days).
Other Name: Sustiva |
CYP2B6*6/*6
Efavirenz clearance in this genotype was compared with the other genotypes
|
Drug: Efavirenz
The metabolism and pharmacokinetics of efavirenz were assessed at a single 600 mg oral dose of efavirenz and after subjects took multiple doses of efavirenz (600 mg/day orally for 17 days).
Other Name: Sustiva |
- Effect of CYP2B6 Genotype on Efavirenz Clearance [ Time Frame: Efavirenz clearance at single dose and multiple dose stratified by CYP2B6 genotypes ]Efavirenz clearance is a measure of rate of elimination of the drug from the body. We used this measure to evaluate differences in rate of elimination of efavirenz at a single dose and after multiple dosing within three CYP2B6 genotypes (CYP2B6*1/*1, *1/*6 and CYP2B6*6/*6). Efavirenz clearance was measured in normal metabolizer of CYP2B6 (CYP2B6*1/*1 genotype), intermediate metabolizer (CYP2B6*1/*6) and slow metabolizer (CYP2B6*6/*6) at a single 600 mg oral dose of efavirenz and then after multiple dosing (autoinduction), i.e., the administration of efavirenz (600 mg/day) for 17 days. Single and multiple dose efavirenz clearance was measured and compared to determine the extent of autoinduction within this genotype group.

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Ages Eligible for Study: | 18 Years to 49 Years (Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Male and female subjects between 18 and 49 years old.
- HIV negative. All potential subjects will be HIV tested at screening visit.
- Healthy individuals without any significant medical condition.
- Adherence to the study dietary restrictions.
- Nonsmoker or individuals willing to refrain from smoking or use of tobacco or marijuana for at lest one month prior to and until the completion of the study. The entire study lasts for 30 days.
- Ability to commit the time requested for this study.
Exclusion Criteria:
- History or current HIV infection.
- Life style that places you at a higher risk for contracting HIV (e.g. drug abuse, excessive alcohol drinking, and having multiple sexual partners).
- Does not consent to HIV testing.
- Underweight (weigh less than 52 kg or 114 lb) or overweight (body mass index (BMI) greater than 32).
- History or current alcohol or drug abuse (more than 3 alcoholic drinks per day on a regular basis).
- History of intolerance or allergic reaction (e.g. rash) to efavirenz, midazolam, tolbutamide, caffeine, or omeprazole.
- History or current significant health conditions such as heart, liver, or kidney.
- History or current psychiatric illness such as depression, anxiety, or nervousness.
- History or current gastrointestinal disorders such as persistent diarrhea or malabsorption that would interfere with the absorption of orally administered drugs.
- Individuals having a serious infection within the last month.
- Donation of blood within the past two months.
- Blood hemoglobin less than 12.5 mg/dl.
- Individuals who are regularly taking prescriptions, over-the-counter, herbal or dietary supplements, alternative medications, or hormonal agents (i.e. oral contraceptives, intera-uterine device with hormones).
- Females with a positive pregnancy test.
- Breastfeeding.
- Females of child-bearing potential who are unable or unwilling to either practice abstinence or use two non-hormonal forms of birth control (e.g. condom, contraceptive foams) up until the study completion, which will take a total of 30 days.
- Participation in a research study or use of an investigational drug in the last two months.
- An employee or student under supervision of any of the investigators of this study.
- Individuals who cannot state a good understanding of this study including risks and requirements; are unable to follow the rules of this study.
- Individuals with a gene type (DNA) that does not match one of the available genetic slot categories.

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): NCT00668395
United States, Indiana | |
Indiana Clinical Research Center (ICRC) | |
Indianapolis, Indiana, United States, 46202 | |
Indiana University | |
Indianapolis, Indiana, United States, 46202 |
Principal Investigator: | Zeruesenay Desta, PhD | Indiana University |
Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Indiana University |
ClinicalTrials.gov Identifier: | NCT00668395 |
Other Study ID Numbers: |
1010002585 | 0704-14 |
First Posted: | April 29, 2008 Key Record Dates |
Results First Posted: | September 26, 2014 |
Last Update Posted: | September 26, 2014 |
Last Verified: | September 2014 |
CYP2B6 Efavirenz Pharmacokinetics Pharmacogenetics Drug-Interactions |
Efavirenz Reverse Transcriptase Inhibitors Nucleic Acid Synthesis Inhibitors Enzyme Inhibitors Molecular Mechanisms of Pharmacological Action Antiviral Agents Anti-Infective Agents |
Cytochrome P-450 CYP2C9 Inhibitors Cytochrome P-450 Enzyme Inhibitors Cytochrome P-450 CYP2C19 Inhibitors Cytochrome P-450 CYP2B6 Inducers Cytochrome P-450 Enzyme Inducers Cytochrome P-450 CYP3A Inducers |