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Completed

NCT Number: NCT02019875

CYP3A4 Activity and Mineral Homeostasis

The purpose of this study is to determine whether changes in the activity of the enzyme CYP3A4 can change the Vitamin D and bone mineral homeostasis.

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Key information

Conditions

Vitamin D and Calcium Homeostasis

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Early Phase 1

Primary location

University of Washington

Seattle, Washington, 98195, United States

About this study

Healthy volunteers will receive one of six interventions for 14 days (determined by randomization):a). 200 mL of water once a day; b) rifampin 600 mg once a day; c) 200 mL of grapefruit juice once a day for 8 days plus rifampin 600 mg once a day for 14 days; d) clarithromycin 250 mg twice a day; f) clarithromycin 250 mg twice a day plus rifampin 600 mg once a day.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Subjects with no history of significant medical conditions including cardiac, pulmonary, gastrointestinal, or renal disease, HIV, diabetes mellitus or Hepatitis B or C
  • Subjects will be males or females 18-60 years of age
  • Subjects must read and understand English
  • Subjects must be able to provide informed consent
  • Subjects must be willing to avoid prescription medications, OTC drugs, dietary supplements and foods that are known to modulate CYP3A4 expression or activity
  • Subjects must be willing to maintain a consistent consumption of calcium and Vitamin D during the study and maintain a daily logbook of their dietary consumption
  • Women not currently pregnant or lactating. In addition, women participants of childbearing age must be willing to utilize a barrier method of birth control (sterilization will be acceptable)
  • Subjects will have no known allergies to the study drugs to be used
  • Subject's corrected QTc interval obtained by electrocardiogram will be ≤ 430 ms in men or ≤ 450 ms in women

Exclusion criteria

  • Subjects with any significant chronic medical condition, including cardiac, pulmonary, gastrointestinal, or renal disease, HIV, diabetes mellitus or Hepatitis B or C
  • Subjects less than 18 or greater than 60 years of age
  • Subjects unable to read and understand English
  • Subjects unable to provide informed consent
  • Subjects unable to avoid prescription medications, OTC drugs, dietary supplements and foods that are known to modulate CYP3A4 expression or activity
  • Subjects not willing to maintain a consistent consumption of calcium and Vitamin D during the study and maintain a daily logbook of their dietary consumption
  • Women who are pregnant or lactating and women participants of childbearing age not willing to utilize a barrier method of birth control (sterilization will be acceptable)
  • Subjects with allergies to rifampin, clarithromycin or grapefruit juice
  • Potential participants will be excluded if they are concurrently participating in another research study
  • Subjects with corrected QTc interval > 430 ms in men or > 450 ms in women on electrocardiogram

Treatment and study plan

Rifampin

Drug

P450 inducer

Other names: Rifadin

Clarithromycin

Drug

CYP3A4 and Pgp inhibitor in both intestine and liiver

Other names: Biaxin

Grapefruit Juice

Other

CYP3A4 inhibitor in intestine

Placebo

Other

Primary outcomes

  1. 1, 25(OH) D3 Vitamin D

    Time frame: Samples will be collected on days 1, 4 and 7, and day 22 (last day of intervention). Treatment began on day 8. Data presented is day 22 concentration - Baseline (the average of day 1, day 4 and day 7 concentrations).

    Serum 1, 25(OH) D3 Vitamin D

  2. 25(OH) D3 Vitamin D

    Time frame: Samples will be collected on days 1, 4 and 7, and day 22 (last day of intervention). Treatment began on day 8. Data presented is day 22 concentration - Baseline (the average of day 1, day 4 and day 7 concentrations).

    Serum 25(OH) D3 Vitamin D

  3. Parathyroid Hormone

    Time frame: Samples will be collected on days 1, 4 and 7, and day 22 (last day of intervention). Treatment began on day 8. Data presented is day 22 concentration - Baseline (the average of day 1, day 4 and day 7 concentrations).

    Blood Parathyroid Hormone

  4. Osteocalcin

    Time frame: Samples will be collected on days 1, 4 and 7, and day 22 (last day of intervention). Treatment began on day 8. Data presented is day 22 concentration - Baseline (the average of day 1, day 4 and day 7 concentrations).

    Serum Osteocalcin

  5. Calcium, Ionized

    Time frame: Samples will be collected on days 1, 4 and 7, and day 22 (last day of intervention). Treatment began on day 8. Data presented is day 22 concentration - Baseline (the average of day 1, day 4 and day 7 concentrations).

    Serum

  6. Calcium/Creatinine (mg/g)

    Time frame: Samples will be collected on days 1, 4 and 7, and day 22 (last day of intervention). Treatment began on day 8. Data presented is day 22 concentration - Baseline (the average of day 1, day 4 and day 7 concentrations).

    Urine Calcium/Creatinine (mg/g)

  7. Phosphate/Creatinine (mg/g)

    Time frame: Samples will be collected on days 1, 4 and 7, and day 22 (last day of intervention). Treatment began on day 8. Data presented is day 22 concentration - Baseline (the average of day 1, day 4 and day 7 concentrations).

    Urine Phosphate/Creatinine(mg/g)

Sponsors and collaborators

Lead sponsor

University of Washington

Other

Collaborators

  • National Institute of General Medical Sciences (NIGMS)

Registry information

Official study title

Effect of Modulating CYP3A4 Activity on Mineral Homeostasis

Important dates

Study start
2014
Primary completion
2020
Study completion
2020
First posted
Dec 24, 2013
Registry last updated
Apr 19, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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