Determine the Effects of Gene Differences and Voriconazole on Enzyme CYP2B6 Activity in the Liver in Healthy Volunteers

Study Overview
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Brief Summary
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The purpose of this study is to see if administration of medicines and genetic differences affects the activity of a liver enzyme called CYP2B6 in healthy volunteers.

Detailed Description
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The investigators will test the hypothesis that CYP2B6 genetic variants that show effects in vitro also influence the in vivo activity of CYP2B6 and its responsiveness to metabolic inhibition, using the metabolism of efavirenz (100 mg dose) as a marker of activity. The metabolism and pharmacokinetics of efavirenz will be determined in a total of 60 healthy volunteers with CYP2B6*1/*1, CYP2B6*1*6 and CYP2B6*6*6 at baseline (control) and after pretreatment with voriconazole.

Official Title
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Effect of Cytochrome P450 2B6 Genetic Polymorphism and Voriconazole on CYP2B6 Activity in Healthy Volunteers

Conditions
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Efavirenz, Metabolism and Pharmacokinetics Changes

Intervention / Treatment
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* Drug: Efavirenz
* Drug: voriconazole


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female subject between 18 and 55 years of age. Healthy individuals without any significant medical conditions as determined by a screening performed at University. Adherence to the study dietary and medication restrictions. Willingness to refrain from smoking or use of tobacco or marijuana one week before the start of the study and until completion of the study which will be a total of 17 days. Ability to commit the time requested for this study. Exclusion Criteria: Underweight (weighs less than 50kg or 110lb) or over weight [body mass index (BMI) greater than 32]. Drug or alcohol abuse (more than 3 alcoholic drinks per day on a regular basis). History of intolerance or allergic reaction (e.g. rash) to efavirenz and/or voriconazole. Significant health conditions such heart, gastrointestinal disorders, liver, or kidney diseases that may be exacerbated during the course of the study. History or current psychiatric illness (e.g. depression, anxiety, or nervousness). History or current eye sight disturbances (e.g. blurred vision). Serious infection within the last 2 weeks. Blood donation within the past two months. Screening results that do not fall in a healthy range. Regularly taking prescriptions (except hormonal agents, e.g. oral contraceptives), over-the-counter, herbal or dietary supplements, and alternative medications and are unable or unwilling to stop taking them one week before and during the study periods. Female with a positive pregnancy test. Female breastfeeding. Females of child-bearing potential who are unable or unwilling to either practice abstinence or use appropriate birth control up until the study completion, which will take a total of 17 days. Participation in a research study involving intensive blood sampling and/or have use study drugs in the last two months. Employed or student under supervision of any of the investigators of this study. Inability to state a good understanding of this study including risks and requirements, and inability to follow the rules of this study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: CYP2B6<br>Healthy volunteers will receive Efavirenz and Vericonazole as follow: In phase 1 day 1 (control phase) a single 100mg dose of efavirenz will be administered. In phase 2 (voriconazole pretreatment phase), the subject will be pretreated with voriconazole (400mg twice daily on phase 2 day 8 and then 200mg twice daily for the next consecutive 8 days. In phase 3 (efavirenz plus voriconazole phase), the subject will receive on phase 3 day 10 100mg single dose of efavirenz along with 200mg of voriconazole twice daily. | Drug: Efavirenz<br>* In phase 1 day 1 (control phase) a single 100mg dose of efavirenz will be administered. In phase 2 (voriconazole pretreatment phase), the subject will be pretreated with voriconazole (400mg twice daily on phase 2 day 8 and then 200mg twice daily for the next consecutive 8 days. In phase 3 (efavirenz plus voriconazole phase), the subject will receive on phase 3 day 10 100mg single dose of efavirenz along with 200mg of voriconazole twice daily.<br>* Other names: Sustiva;Drug: voriconazole<br>* In phase 1 day 1 (control phase) a single 100mg dose of efavirenz will be administered. In phase 2 (voriconazole pretreatment phase), the subject will be pretreated with voriconazole (400mg twice daily on phase 2 day 8 and then 200mg twice daily for the next consecutive 8 days. In phase 3 (efavirenz plus voriconazole phase), the subject will receive on phase 3 day 10 100mg single dose of efavirenz along with 200mg of voriconazole twice daily.<br>* Other names: Vfend;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measure Efavirenz Clearance | Effect of steady-state voriconazole on efavirenz Clearance in healthy volunteers (n=61) administered a single 100 mg oral dose of efavirenz at baseline (control phase) and after treatment with voriconazole to steady-state. | Baseline, 30 min, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 16 and 24h after efavirenz | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cytochrome P450, CYP2B6, Voriconazole, Efavirenz, Pharmacokinetics, Drug-Interactions, Pharmacogenetics, Healthy volunteers