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Showing 1–24 of 61 matching trials from the live ClinicalTrials.gov search.
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Filters: Intervention: Tetrahydrobiopterin (BH4) Clear all
Completed No phase listed Observational Accepts healthy volunteers

The Effects of Kuvan on Functional Brain Connectivity in Individuals With Phenylketonuria (PKU)

NCT00964236
View directory record Official record
Conditions
Phenylketonuria
Interventions
Sapropterin
Drug
Lead sponsor
University of Missouri-Columbia
Other
Eligibility
6 Years and older
Enrollment
20 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2009 – 2011
U.S. locations
1
States / cities
Columbia, Missouri
Source: ClinicalTrials.gov public record
Updated Jan 3, 2018 · Synced Sep 29, 2026, 10:19 AM 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 Jan 31, 2016 · Synced Sep 29, 2026, 10:19 AM EDT
Completed Phase 4 Interventional Results available

The Effectiveness of Kuvan in Amish PKU Patients

NCT02677870
View directory record Official record
Conditions
Phenylketonuria
Interventions
saproterin dihydrochloride, Diet treatment
Drug · Other
Lead sponsor
University Hospitals Cleveland Medical Center
Other
Eligibility
2 Years to 60 Years
Enrollment
7 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2018 – 2019
U.S. locations
1
States / cities
Cleveland, Ohio
Source: ClinicalTrials.gov public record
Updated Apr 26, 2022 · Synced Sep 29, 2026, 10:19 AM EDT
Completed No phase listed Observational

PKUDOS: Phenylketonuria (PKU) Demographic, Outcomes, and Safety Registry

NCT00778206
View directory record Official record
Conditions
Phenylketonuria, Hyperphenylalaninaemia
Interventions
Kuvan
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
Not listed
Enrollment
1,887 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2008 – 2021
U.S. locations
45
States / cities
Los Angeles, California • Orange, California • San Diego, California + 38 more
Source: ClinicalTrials.gov public record
Updated Oct 11, 2022 · Synced Sep 29, 2026, 10:19 AM EDT
Terminated Not applicable Interventional Accepts healthy volunteers Results available

Bone Mineral Density in Adults With Hyperphenylalaninemia on Kuvan Therapy

NCT01541397
View directory record Official record
Conditions
Hyperphenylalaninemia, Phenylketonuria
Interventions
Sapropterin
Drug
Lead sponsor
The University of Texas Health Science Center, Houston
Other
Eligibility
18 Years to 50 Years
Enrollment
6 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2011 – 2012
U.S. locations
1
States / cities
Houston, Texas
Source: ClinicalTrials.gov public record
Updated Jul 6, 2015 · Synced Sep 29, 2026, 10:19 AM 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 18, 2023 · Synced Sep 29, 2026, 10:19 AM EDT
Completed Not applicable Interventional Results available

Tetrahydrobiopterin Treatment in Children With Idiopathic Cognitive Developmental Disorders

NCT01141595
View directory record Official record
Conditions
Autism Spectrum Disorder
Interventions
sapropterin dihydrochloride
Drug
Lead sponsor
The University of Texas Health Science Center, Houston
Other
Eligibility
2 Years to 6 Years
Enrollment
10 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2010 – 2011
U.S. locations
1
States / cities
Little Rock, Arkansas
Source: ClinicalTrials.gov public record
Updated Mar 31, 2014 · Synced Sep 29, 2026, 10:19 AM EDT
Completed Not applicable Interventional Results available

Rhode Island Diastolic Dysfunction - Heart Failure

NCT02353312
View directory record Official record
Conditions
Heart Failure, Cardiovascular Disease
Interventions
Kuvan
Drug
Lead sponsor
Providence VA Medical Center
Federal
Eligibility
18 Years and older
Enrollment
28 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2015 – 2018
U.S. locations
1
States / cities
Providence, Rhode Island
Source: ClinicalTrials.gov public record
Updated Jul 2, 2025 · Synced Sep 29, 2026, 10:19 AM EDT
Completed No phase listed Observational Accepts healthy volunteers

Sapropterin in Individuals With Phenylketonuria

NCT00730080
View directory record Official record
Conditions
Phenylketonuria
Interventions
Sapropterin (Kuvan)
Drug
Lead sponsor
Washington University School of Medicine
Other
Eligibility
6 Years to 50 Years
Enrollment
45 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2008 – 2018
U.S. locations
1
States / cities
St Louis, Missouri
Source: ClinicalTrials.gov public record
Updated Jun 17, 2018 · Synced Sep 29, 2026, 10:19 AM 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 22, 2026 · Synced Sep 29, 2026, 10:19 AM EDT
Terminated No phase listed Observational

Behavioral Effects of Kuvan in Children With Mild Phenylketonuria

NCT00827762
View directory record Official record
Conditions
Phenylketonuria
Interventions
Kuvan
Drug
Lead sponsor
Washington University School of Medicine
Other
Eligibility
6 Years to 18 Years
Enrollment
2 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2009 – 2010
U.S. locations
4
States / cities
Chicago, Illinois • Columbia, Missouri • St Louis, Missouri + 1 more
Source: ClinicalTrials.gov public record
Updated Dec 4, 2013 · Synced Sep 29, 2026, 10:19 AM 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 7, 2015 · Synced Sep 29, 2026, 10:19 AM EDT
Completed No phase listed Observational Accepts healthy volunteers

Evaluation of Behavior, Executive Function, Neurotransmitter Function and Genomic Expression Kuvan Nonresponders

NCT01274026
View directory record Official record
Conditions
Phenylketonuria, Behavior and Behavior Mechanisms, PAH Gene Expression
Interventions
sapropterin dihydrochloride
Drug
Lead sponsor
Tulane University School of Medicine
Other
Eligibility
2 Years to 21 Years
Enrollment
21 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2011 – 2013
U.S. locations
1
States / cities
New Orleans, Louisiana
Source: ClinicalTrials.gov public record
Updated Aug 13, 2023 · Synced Sep 29, 2026, 10:19 AM EDT
Completed No phase listed Observational Accepts healthy volunteers

PKU Skin Stripping

NCT04368624
View directory record Official record
Conditions
Phenylketonurias
Interventions
Skin Tape, Blood Draw
Other · Diagnostic Test
Lead sponsor
Children's Hospital Medical Center, Cincinnati
Other
Eligibility
Not listed
Enrollment
86 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2015 – 2021
U.S. locations
1
States / cities
Cincinnati, Ohio
Source: ClinicalTrials.gov public record
Updated Jul 27, 2021 · Synced Sep 29, 2026, 10:19 AM EDT
Completed Not applicable Interventional Results available

Impact of KUVAN® on Gastric Relaxation in Women With Diabetic Gastroparesis.

NCT01135186
View directory record Official record
Conditions
Gastroparesis
Interventions
sapropterin dihydrochloride
Drug
Lead sponsor
Stanford University
Other
Eligibility
18 Years to 65 Years · Female only
Enrollment
9 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2010 – 2012
U.S. locations
1
States / cities
Stanford, California
Source: ClinicalTrials.gov public record
Updated Sep 9, 2019 · Synced Sep 29, 2026, 10:19 AM EDT
Completed Early Phase 1 Interventional

Exercise and NO in HFrEF

NCT03136029
View directory record Official record
Conditions
Heart Failure With Reduced Ejection Fraction
Interventions
Antioxidant, Tetrahydrobiopterin (BH4), Exercise training
Dietary Supplement · Other
Lead sponsor
VA Office of Research and Development
Federal
Eligibility
18 Years and older
Enrollment
68 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2018 – 2025
U.S. locations
1
States / cities
Salt Lake City, Utah
Source: ClinicalTrials.gov public record
Updated Aug 5, 2025 · Synced Sep 29, 2026, 10:19 AM 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 12, 2017 · Synced Sep 29, 2026, 10:19 AM 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 25, 2018 · Synced Sep 29, 2026, 10:19 AM 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 May 31, 2015 · Synced Sep 29, 2026, 10:19 AM EDT
Completed Phase 1 Interventional

6R-BH4 Pulmonary Arterial Hypertension Study

NCT00435331
View directory record Official record
Conditions
Pulmonary Arterial Hypertension
Interventions
sapropterin dihydrochloride (6R-BH4)
Drug
Lead sponsor
Vanderbilt University
Other
Eligibility
18 Years and older
Enrollment
14 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2008
U.S. locations
1
States / cities
Nashville, Tennessee
Source: ClinicalTrials.gov public record
Updated Jun 18, 2013 · Synced Sep 29, 2026, 10:19 AM EDT
Completed Phase 3 Interventional Results available

Study of Phenoptin to Increase Phenylalanine Tolerance in Phenylketonuric Children on a Phenylalanine-restricted Diet

NCT00272792
View directory record Official record
Conditions
Phenylketonurias
Interventions
Sapropterin Dihydrochloride, Placebo
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
4 Years to 12 Years
Enrollment
45 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2006
U.S. locations
9
States / cities
Los Angeles, California • Oakland, California • Sacramento, California + 6 more
Source: ClinicalTrials.gov public record
Updated Aug 12, 2015 · Synced Sep 29, 2026, 10:19 AM 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 20, 2017 · Synced Sep 29, 2026, 10:19 AM 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 6, 2021 · Synced Sep 29, 2026, 10:19 AM 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 24, 2020 · Synced Sep 29, 2026, 10:19 AM EDT