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

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified June 2008 by University of Oxford.
Recruitment status was:  Recruiting
BioMarin Pharmaceutical
Information provided by:
University of Oxford Identifier:
First received: January 17, 2007
Last updated: August 6, 2008
Last verified: June 2008
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.

Condition Intervention Phase
Coronary Artery Disease
Drug: 6R-BH4
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator)
Primary Purpose: Treatment
Official Title: A Randomised, Placebo-Controlled Study of Two Doses of Oral 6R-BH4 on Vascular Function in Subjects With Coronary Artery Disease

Resource links provided by NLM:

Further study details as provided by University of Oxford:

Primary Outcome Measures:
  • Vascular function using non-invasive magnetic resonance imaging (MRI). [ Time Frame: Pre- and post- treatment with 6R-BH4 or placebo ]

Secondary Outcome Measures:
  • Laboratory measures of vascular function. [ Time Frame: At time of CABG surgery ]

Estimated Enrollment: 66
Study Start Date: November 2006
Estimated Study Completion Date: February 2009
Estimated Primary Completion Date: February 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1
700mg/day 6R-BH4
Drug: 6R-BH4
6R-BH4 tablets 700mg/day, 6R-BH4 tablets 400mg/day or placebo
Other Name: Sapropterin dihydrochloride
Active Comparator: 2
400mg/day 6R-BH4
Drug: 6R-BH4
6R-BH4 tablets 700mg/day, 6R-BH4 tablets 400mg/day or placebo
Other Name: Sapropterin dihydrochloride
Placebo Comparator: 3
Drug: 6R-BH4
6R-BH4 tablets 700mg/day, 6R-BH4 tablets 400mg/day or placebo
Other Name: Sapropterin dihydrochloride

Detailed Description:

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.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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
  Contacts and Locations
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Please refer to this study by its identifier: NCT00423280

Contact: Colin Cunnington, MBChB MRCP +44-1865-221866

United Kingdom
Department of Cardiovascular Medicine, University of Oxford Recruiting
Oxford, United Kingdom, OX3 9DU
Sponsors and Collaborators
University of Oxford
BioMarin Pharmaceutical
Principal Investigator: Keith M Channon, MD FRCP University of Oxford
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Mrs Heather House, University of Oxford Identifier: NCT00423280     History of Changes
Other Study ID Numbers: 06/Q1604/114
Study First Received: January 17, 2007
Last Updated: August 6, 2008

Keywords provided by University of Oxford:
Nitric Oxide
Magnetic Resonance Imaging

Additional relevant MeSH terms:
Coronary Artery Disease
Myocardial Ischemia
Coronary Disease
Heart Diseases
Cardiovascular Diseases
Arterial Occlusive Diseases
Vascular Diseases processed this record on April 28, 2017