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ClinicalTrials.gov public records Last synced Oct 21, 2026, 6:13 PM EDT

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Showing 1–24 of 33 matching trials from the live ClinicalTrials.gov search.
Filters: Intervention: 6R-BH4 Clear all
Completed Phase 2 Interventional Results available

Tetrahydrobiopterin in Patients With Chronic Kidney Disease (CKD) and Albuminuria

NCT00625820
View directory record Official record
Conditions
Kidney Disease, Albuminuria
Interventions
6R BH4, Vitamin C
Drug · Dietary Supplement
Lead sponsor
University of Michigan
Other
Eligibility
18 Years to 75 Years
Enrollment
17 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2008
U.S. locations
1
States / cities
Ann Arbor, Michigan
Source: ClinicalTrials.gov public record
Updated Oct 18, 2016 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 2 Interventional Results available

A Phase 2 Study of the Effects of 6R-BH4 in Subjects With Sickle Cell Disease

NCT00445978
View directory record Official record
Conditions
Sickle Cell Disease
Interventions
Sapropterin Dihydrochloride
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
15 Years and older
Enrollment
32 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2007 – 2009
U.S. locations
12
States / cities
Washington D.C., District of Columbia • Augusta, Georgia • Savannah, Georgia + 9 more
Source: ClinicalTrials.gov public record
Updated Feb 25, 2021 · Synced Oct 21, 2026, 6:13 PM EDT
Withdrawn Phase 1 Interventional Accepts healthy volunteers

O2 Transport and Utilization in Health and Lung Disease

NCT04014712
View directory record Official record
Conditions
COPD, Tetrahydrobiopterin Deficiency, Oxidative Stress
Interventions
Tetrahydrobiopterin, Placebo oral tablet
Drug
Lead sponsor
University of Massachusetts, Amherst
Other
Eligibility
18 Years to 85 Years
Healthy volunteers
Accepts healthy volunteers
Timeline
2021 – 2022
U.S. locations
1
States / cities
Amherst, Massachusetts
Source: ClinicalTrials.gov public record
Updated Dec 19, 2023 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 1Phase 2 Interventional Results available

Study of Kuvan Treatment in Adults With GTPCH Deficiency

NCT01425528
View directory record Official record
Conditions
GTP Cyclohydrolase Deficiency
Interventions
Sapropterin
Drug
Lead sponsor
University of Utah
Other
Eligibility
18 Years and older
Enrollment
12 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2011 – 2013
U.S. locations
1
States / cities
Salt Lake City, Utah
Source: ClinicalTrials.gov public record
Updated Apr 1, 2025 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 2 Interventional Accepts healthy volunteers Results available

Long Term Nitric Oxide Bioavailability on Vascular Health in Chronic Obstructive Pulmonary Disease

NCT02774226
View directory record Official record
Conditions
Chronic Obstructive Pulmonary Disease (COPD)
Interventions
Tetrahydrobiopterin (BH4), Antioxidant Cocktail
Drug · Dietary Supplement
Lead sponsor
Augusta University
Other
Eligibility
18 Years and older
Enrollment
15 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2015 – 2018
U.S. locations
1
States / cities
Augusta, Georgia
Source: ClinicalTrials.gov public record
Updated Feb 23, 2021 · Synced Oct 21, 2026, 6:13 PM EDT
Recruiting Phase 1 Interventional

Novel Approaches for Improving Vascular Function in Veterans With HFpEF

NCT06312748
View directory record Official record
Conditions
Heart Failure With Preserved Ejection Fraction, Inflammation
Interventions
L-Citrulline, Placebo for L-Citrulline, BH4, Placebo for BH4, Atorvastatin, Placebo for Atorvastatin
Drug
Lead sponsor
VA Office of Research and Development
Federal
Eligibility
18 Years and older
Enrollment
90 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2021 – 2030
U.S. locations
1
States / cities
Salt Lake City, Utah
Source: ClinicalTrials.gov public record
Updated Apr 23, 2026 · Synced Oct 21, 2026, 6:13 PM EDT
Completed No phase listed Observational Accepts healthy volunteers Results available

Nutritional and Neurotransmitter Changes in PKU Subjects on BH4

NCT00688844
View directory record Official record
Conditions
Phenylketonuria
Interventions
KuvanTM Therapy
Drug
Lead sponsor
Emory University
Other
Eligibility
4 Years and older
Enrollment
58 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2008 – 2010
U.S. locations
2
States / cities
Atlanta, Georgia • Decatur, Georgia
Source: ClinicalTrials.gov public record
Updated Jun 8, 2015 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 2 Interventional Results available

Safety and Efficacy Study of Phenoptin in Subjects With Hyperphenylalaninemia Due to BH4 Deficiency

NCT00355264
View directory record Official record
Conditions
Tetrahydrobiopterin Deficiencies, Hyperphenylalaninemia, Non-Phenylketonuric
Interventions
Phenoptin
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
Not listed
Enrollment
12 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2006 – 2009
U.S. locations
9
States / cities
Los Angeles, California • Chicago, Illinois • Minneapolis, Minnesota + 6 more
Source: ClinicalTrials.gov public record
Updated Sep 25, 2020 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 1Phase 2 Interventional Results available

A Study of PTC923 (CNSA-001) in Primary Tetrahydrobiopterin (BH4) Deficient Participants With Hyperphenylalaninemia

NCT03519711
View directory record Official record
Conditions
BH4 Deficiency, Hyperphenylalaninemia
Interventions
PTC923
Drug
Lead sponsor
PTC Therapeutics
Industry
Eligibility
12 Months and older
Enrollment
8 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2019 – 2020
U.S. locations
4
States / cities
Minneapolis, Minnesota • Dallas, Texas • Salt Lake City, Utah + 1 more
Source: ClinicalTrials.gov public record
Updated Nov 14, 2023 · Synced Oct 21, 2026, 6:13 PM EDT
Terminated Phase 2 Interventional Results available

Oral 6R-BH4 for the Treatment of Isolated Systolic Hypertension and Endothelial Dysfunction

NCT00802893
View directory record Official record
Conditions
Isolated Systolic Hypertension, Endothelial Dysfunction
Interventions
6R-BH4, Placebo
Drug · Other
Lead sponsor
Johns Hopkins University
Other
Eligibility
40 Years and older
Enrollment
3 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2008 – 2009
U.S. locations
1
States / cities
Baltimore, Maryland
Source: ClinicalTrials.gov public record
Updated Aug 21, 2017 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Not applicable Interventional Accepts healthy volunteers Results available

Nitric Oxide Bioavailability in Chronic Obstructive Pulmonary Disease (COPD)

NCT01398943
View directory record Official record
Conditions
Pulmonary Disease, Chronic Obstructive
Interventions
Tetrahydrobiopterin (BH4), Antioxidant Cocktail
Drug · Dietary Supplement
Lead sponsor
Augusta University
Other
Eligibility
18 Years and older
Enrollment
60 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2010 – 2015
U.S. locations
1
States / cities
Augusta, Georgia
Source: ClinicalTrials.gov public record
Updated Dec 11, 2017 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Not applicable Interventional Results available

Fluorodeoxyglucose Positron Emission Tomography (FDG PET) Findings in Patients With Phenylketonuria Before and After KUVAN Therapy

NCT00986973
View directory record Official record
Conditions
Phenylketonuria
Interventions
Sapropterin
Drug
Lead sponsor
Children's Hospital of Philadelphia
Other
Eligibility
18 Years to 50 Years
Enrollment
6 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2010 – 2011
U.S. locations
1
States / cities
Philadelphia, Pennsylvania
Source: ClinicalTrials.gov public record
Updated Jun 8, 2015 · Synced Oct 21, 2026, 6:13 PM EDT
Recruiting Phase 1 Interventional Accepts healthy volunteers

: Vascular Function in Health and Disease

NCT02966665
View directory record Official record
Conditions
Chronic Obstructive Pulmonary Disease, Pulmonary Artery Hypertension, Heart Failure, Hypertension
Interventions
Maximum Exercise Tests, BH4, L-NMMA, Vitamin C, Vitamin E, α-Lipoic Acid and L-Ascorbate, BQ-123, Fexofenadine, Ranitidine, Angiotensin-II, Valsartan, Acetylcholine, Sodium Nitroprusside, Angiotensin-II, Norepinephrine, Phentolamine, BQ-123, MitoQ, BH4
Other · Drug
Lead sponsor
D. Walter Wray
Other
Eligibility
18 Years and older
Enrollment
420 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2008 – 2030
U.S. locations
1
States / cities
Salt Lake City, Utah
Source: ClinicalTrials.gov public record
Updated Sep 25, 2026 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 2 Interventional Results available

Kuvan Therapy in Phenylketonuria (PKU): The Effect of Blood Phenylalanine Concentration on Kuvan Response

NCT00841100
View directory record Official record
Conditions
Phenylketonuria
Interventions
Kuvan, Diet
Drug · Other
Lead sponsor
University of Miami
Other
Eligibility
4 Years and older
Enrollment
21 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2008 – 2011
U.S. locations
1
States / cities
Miami, Florida
Source: ClinicalTrials.gov public record
Updated Dec 3, 2019 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 1Phase 2 Interventional Results available

Kuvan in People With Schizophrenia and Schizoaffective Disorder

NCT01706965
View directory record Official record
Conditions
Schizophrenia, Schizoaffective Disorder
Interventions
Kuvan, Multivitamin
Drug
Lead sponsor
New York State Psychiatric Institute
Other
Eligibility
18 Years to 64 Years
Enrollment
27 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2012 – 2016
U.S. locations
1
States / cities
New York, New York
Source: ClinicalTrials.gov public record
Updated Sep 13, 2017 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 2 Interventional Results available

A Phase 2 Study of the Effects of Sapropterin Dihydrochloride on Symptomatic Peripheral Arterial Disease

NCT00403494
View directory record Official record
Conditions
Intermittent Claudication
Interventions
Placebo, Sapropterin Dihydrochloride
Other · Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
40 Years to 80 Years
Enrollment
190 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2006 – 2009
U.S. locations
17
States / cities
Scottsdale, Arizona • Sacramento, California • San Diego, California + 14 more
Source: ClinicalTrials.gov public record
Updated Jan 7, 2021 · Synced Oct 21, 2026, 6:13 PM EDT
Terminated Phase 1 Interventional Accepts healthy volunteers

Response to Phenylketonuria to Tetrahydrobiopterin (BH4)

NCT00244218
View directory record Official record
Conditions
Phenylketonuria
Interventions
tetrahydrobiopterin (BH4)
Drug
Lead sponsor
The University of Texas Medical Branch, Galveston
Other
Eligibility
10 Years and older
Enrollment
57 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2005 – 2015
U.S. locations
1
States / cities
Galveston, Texas
Source: ClinicalTrials.gov public record
Updated Sep 21, 2021 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 3 Interventional Results available

Safety and Therapeutic Effects of Sapropterin Dihydrochloride on Neuropsychiatric Symptoms in Phenylketonuria (PKU) Patients

NCT01114737
View directory record Official record
Conditions
Phenylketonuria
Interventions
Sapropterin dihydrochloride, Placebo
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
8 Years to 65 Years
Enrollment
206 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2010 – 2013
U.S. locations
26
States / cities
La Jolla, California • Los Angeles, California • Palo Alto, California + 23 more
Source: ClinicalTrials.gov public record
Updated Feb 1, 2016 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 1Phase 2 Interventional Accepts healthy volunteers Results available

Systemic Sclerosis (SSc) Vasculopathy: Improved Clinical Monitoring and Treatment

NCT02530996
View directory record Official record
Conditions
Rheumatologic Disease
Interventions
BH4, Vasculopathy assessment, Placebo
Drug · Diagnostic Test
Lead sponsor
VA Office of Research and Development
Federal
Eligibility
18 Years to 95 Years
Enrollment
12 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2016 – 2019
U.S. locations
1
States / cities
Salt Lake City, Utah
Source: ClinicalTrials.gov public record
Updated Apr 5, 2021 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 2 Interventional Accepts healthy volunteers Results available

Exercise Intolerance in Renal Failure

NCT01356966
View directory record Official record
Conditions
Kidney Failure, Chronic
Interventions
Tetrahydrobiopterin, Placebo, Folate
Drug · Dietary Supplement
Lead sponsor
Emory University
Other
Eligibility
18 Years to 75 Years
Enrollment
74 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2011 – 2014
U.S. locations
2
States / cities
Atlanta, Georgia • Decatur, Georgia
Source: ClinicalTrials.gov public record
Updated Jun 1, 2015 · Synced Oct 21, 2026, 6:13 PM EDT
Terminated Phase 2 Interventional Accepts healthy volunteers Results available

Phenylketonuria, Oxidative Stress, and BH4

NCT01395394
View directory record Official record
Conditions
Phenylketonuria
Interventions
Kuvan, Meal Challenge
Drug · Other
Lead sponsor
Emory University
Other
Eligibility
10 Years to 45 Years
Enrollment
12 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2011 – 2013
U.S. locations
1
States / cities
Decatur, Georgia
Source: ClinicalTrials.gov public record
Updated Aug 28, 2014 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Early Phase 1 Interventional

Effects of Tetrahydrobiopterin on Blood Pressure

NCT00208780
View directory record Official record
Conditions
Hypertension
Interventions
Tetrahydrobiopterin
Drug
Lead sponsor
Emory University
Other
Eligibility
18 Years to 75 Years
Enrollment
24 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2004 – 2005
U.S. locations
1
States / cities
Atlanta, Georgia
Source: ClinicalTrials.gov public record
Updated Nov 18, 2013 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Phase 1 Interventional Accepts healthy volunteers

The Effect of Antioxidants on Skin Blood Flow-BH4

NCT03680573
View directory record Official record
Conditions
Cardiovascular Diseases, Cardiovascular Risk Factor, Vasoconstriction
Interventions
Control: Lacated Ringers, Apocynin, Allopurinol, BH4, NG Nitro L Arginine Methyl Ester, Sodium Nitroprusside, Acetyl-ß-methylcholine chloride
Drug
Lead sponsor
The University of Texas at Arlington
Other
Eligibility
18 Years to 35 Years
Enrollment
16 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2018
U.S. locations
1
States / cities
Arlington, Texas
Source: ClinicalTrials.gov public record
Updated Sep 26, 2018 · Synced Oct 21, 2026, 6:13 PM EDT
Completed Early Phase 1 Interventional Accepts healthy volunteers

Sex Hormones and Atherosclerosis Prevention in Perimenopausal Women

NCT02042196
View directory record Official record
Conditions
Menopause, Aging
Interventions
KUVAN, Placebo, Cetrotide, Climara, Placebo transdermal patch
Drug
Lead sponsor
University of Colorado, Denver
Other
Eligibility
18 Years to 70 Years · Female only
Enrollment
100 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2013 – 2016
U.S. locations
1
States / cities
Aurora, Colorado
Source: ClinicalTrials.gov public record
Updated Jul 11, 2019 · Synced Oct 21, 2026, 6:13 PM EDT