Effect of 6R-BH4 Treatment in Coronary Artery Disease (OXBIO Study)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00423280
Recruitment Status : Unknown
Verified June 2008 by University of Oxford.
Recruitment status was:  Recruiting
First Posted : January 18, 2007
Last Update Posted : August 7, 2008
BioMarin Pharmaceutical
Information provided by:
University of Oxford

January 17, 2007
January 18, 2007
August 7, 2008
November 2006
February 2009   (Final data collection date for primary outcome measure)
Vascular function using non-invasive magnetic resonance imaging (MRI). [ Time Frame: Pre- and post- treatment with 6R-BH4 or placebo ]
Improvement in measures of vascular function using non-invasive magnetic resonance imaging (MRI).
Complete list of historical versions of study NCT00423280 on Archive Site
Laboratory measures of vascular function. [ Time Frame: At time of CABG surgery ]
Improvement in laboratory measures of vascular function.
Not Provided
Not Provided
Effect of 6R-BH4 Treatment in Coronary Artery Disease (OXBIO Study)
A Randomised, Placebo-Controlled Study of Two Doses of Oral 6R-BH4 on Vascular Function in Subjects With Coronary Artery Disease
The purpose of this study is to determine the effect of 6R-BH4 on vascular function in patients with coronary artery disease. We hypothesize that 6R-BH4 will improve vascular function in these patients.

Decreased production of nitric oxide (NO) from the endothelium (the layer of cells that forms the lining of all blood vessels) has been shown to contribute to atherosclerosis. NO has multiple beneficial effects on vascular function. Endothelial function can be measured in humans via a number of methods, and endothelial dysfunction has been shown to be a strong adverse predictor of cardiovascular events and mortality.

Tetrahydrobiopterin (BH4) is essential for the production of NO in endothelial cells. 6R-BH4 is a synthetic version of naturally occurring BH4. We aim to investigate the effects of oral 6R-BH4 supplementation on endothelial function in patients with coronary artery disease.

Phase 2
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Treatment
Coronary Artery Disease
Drug: 6R-BH4
6R-BH4 tablets 700mg/day, 6R-BH4 tablets 400mg/day or placebo
Other Name: Sapropterin dihydrochloride
  • Active Comparator: 1
    700mg/day 6R-BH4
    Intervention: Drug: 6R-BH4
  • Active Comparator: 2
    400mg/day 6R-BH4
    Intervention: Drug: 6R-BH4
  • Placebo Comparator: 3
    Intervention: Drug: 6R-BH4

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Unknown status
Same as current
February 2009
February 2009   (Final data collection date for primary outcome measure)

Inclusion Criteria:

  • Multi-vessel coronary artery disease scheduled for coronary artery bypass surgery (CABG)

Exclusion Criteria:

  • Inability to provide informed consent
  • Female subject who is pregnant, lactating or planning pregnancy during course of study
  • Prior clinical diagnosis of heart failure requiring diuretic therapy with evidence of severe left ventricular dysfunction
  • Recent acute coronary event (<4 weeks)
  • Emergency CABG
  • Newly diagnosed diabetes mellitus (<1 month)
  • Body weight >130kg
  • Impaired renal function (creatinine >180umol/l)
  • Elevated liver function tests (ALT >50umol/l or AST >2x normal)
  • Pacemakers, ICDs or metallic implants not compatible with MRI scanning
  • Subjects receiving experimental medications or participating in another study
  • Terminally ill subjects
  • Known hypersensitivity to 6R-BH4
  • Concomitant treatment with methotrexate, levodopa, PDE-3 or PDE-5 inhibitors
Sexes Eligible for Study: All
18 Years and older   (Adult, Senior)
Contact information is only displayed when the study is recruiting subjects
United Kingdom
Not Provided
Not Provided
Mrs Heather House, University of Oxford
University of Oxford
BioMarin Pharmaceutical
Principal Investigator: Keith M Channon, MD FRCP University of Oxford
University of Oxford
June 2008

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP