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ClinicalTrials.gov public records Last synced Oct 5, 2026, 7:42 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Showing 25–48 of 61 matching trials from the live ClinicalTrials.gov search.
Filters: Intervention: Tetrahydrobiopterin (BH4) Clear all
Recruiting Phase 2 Interventional

Neurovascular Transduction During Exercise in Chronic Kidney Disease

NCT02947750
View directory record Official record
Conditions
Renal Insufficiency, Chronic
Interventions
6R-BH4, 6R-BH4 placebo, Folic acid, Exercise training, Stretching, Histidine and beta-alanine supplementation, Histidine and beta-alanine placebo
Drug · Other · Dietary Supplement
Lead sponsor
Emory University
Other
Eligibility
18 Years to 75 Years
Enrollment
150 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2016 – 2027
U.S. locations
3
States / cities
Atlanta, Georgia • Decatur, Georgia
Source: ClinicalTrials.gov public record
Updated May 18, 2026 · Synced Oct 5, 2026, 7:42 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 5, 2026, 7:42 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 5, 2026, 7:42 PM EDT
Completed Phase 3 Interventional

A Phase 3, Multicenter, Open-Label Extension Study of Phenoptin in Subjects With PKU Who Have Elevated Phenylalanine Levels

NCT00225615
View directory record Official record
Conditions
Phenylketonurias
Interventions
sapropterin dihydrochloride
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
8 Years and older
Enrollment
100 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2005 – 2006
U.S. locations
14
States / cities
Los Angeles, California • Oakland, California • Sacramento, California + 11 more
Source: ClinicalTrials.gov public record
Updated Aug 20, 2009 · Synced Oct 5, 2026, 7:42 PM EDT
Completed Phase 2Phase 3 Interventional Results available

Open-Label Extension Study of Kuvan for Autism

NCT00943579
View directory record Official record
Conditions
Autistic Disorder
Interventions
Kuvan®
Drug
Lead sponsor
The Children's Health Council
Other
Eligibility
3 Years to 6 Years
Enrollment
41 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2009 – 2012
U.S. locations
1
States / cities
Palo Alto, California
Source: ClinicalTrials.gov public record
Updated May 2, 2018 · Synced Oct 5, 2026, 7:42 PM EDT
Completed Phase 2 Interventional

Study to Evaluate the Response to and Safety of an 8-Day Course of Phenoptin™ Treatment in Subjects With Phenylketonuria

NCT00104260
View directory record Official record
Conditions
Phenylketonurias
Interventions
sapropterin dihydrochloride
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
8 Years and older
Enrollment
700 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2004 – 2005
U.S. locations
13
States / cities
Los Angeles, California • Oakland, California • New Haven, Connecticut + 10 more
Source: ClinicalTrials.gov public record
Updated Apr 9, 2007 · Synced Oct 5, 2026, 7:42 PM EDT
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 4, 2018 · Synced Oct 5, 2026, 7:42 PM EDT
Withdrawn Phase 2Phase 3 Interventional

Trial of Kuvan in Lesch-Nyhan Disease

NCT00935753
View directory record Official record
Conditions
Behavioral Manifestations of Lesch-Nyhan Disease
Interventions
sapropterin
Drug
Lead sponsor
University of California, San Diego
Other
Eligibility
4 Years and older
Healthy volunteers
Healthy volunteers not accepted
Timeline
2009 – 2010
U.S. locations
1
States / cities
San Diego, California
Source: ClinicalTrials.gov public record
Updated Aug 2, 2019 · Synced Oct 5, 2026, 7:42 PM EDT
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 5, 2026, 7:42 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 5, 2026, 7:42 PM EDT
Active, not recruiting Phase 1 Interventional

The Effects of ATLAS Therapy on Nitric Oxide Bioavailability in Patients With Intermittent Claudication

NCT04800692
View directory record Official record
Conditions
Claudication, Intermittent, Peripheral Artery Disease, Peripheral Vascular Diseases
Interventions
Tetrahydrobiopterin 10 mg/kg, Tetrahydrobiopterin 20 mg/kg, L-Ascorbate, L-Arginine
Drug
Lead sponsor
Louis Messina
Other
Eligibility
18 Years and older
Enrollment
10 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2021 – 2027
U.S. locations
1
States / cities
Worcester, Massachusetts
Source: ClinicalTrials.gov public record
Updated Apr 15, 2026 · Synced Oct 5, 2026, 7:42 PM 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 19, 2013 · Synced Oct 5, 2026, 7:42 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 5, 2026, 7:42 PM EDT
Completed No phase listed Observational

Study to Evaluate the Effects of Kuvan on Individuals With Phenylketonuria (PKU) With Maladaptive Behaviors

NCT00728676
View directory record Official record
Conditions
Phenylketonuria
Interventions
Not listed
Lead sponsor
Shoji Yano
Other
Eligibility
18 Years and older
Enrollment
10 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2008 – 2010
U.S. locations
1
States / cities
Los Angeles, California
Source: ClinicalTrials.gov public record
Updated Jan 18, 2013 · Synced Oct 5, 2026, 7:42 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 5, 2026, 7:42 PM 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 14, 2023 · Synced Oct 5, 2026, 7:42 PM EDT
Withdrawn Phase 2 Interventional

L-arginine Study for Persistent Symptoms of Schizophrenia

NCT04054973
View directory record Official record
Conditions
Schizo Affective Disorder, Schizophrenia
Interventions
L-arginine, Sapropterin Dihydrochloride
Drug
Lead sponsor
University of Massachusetts, Worcester
Other
Eligibility
18 Years to 65 Years
Healthy volunteers
Healthy volunteers not accepted
Timeline
2019 – 2021
U.S. locations
1
States / cities
Worcester, Massachusetts
Source: ClinicalTrials.gov public record
Updated Jan 20, 2022 · Synced Oct 5, 2026, 7:42 PM EDT
Completed Phase 3 Interventional Results available

Effect of Kuvan on Neurocognitive Function, Blood Phenylalanine Level, Safety, and Pharmacokinetics in Children With PKU

NCT00838435
View directory record Official record
Conditions
Phenylketonuria
Interventions
sapropterin dihydrochloride
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
Up to 6 Years
Enrollment
95 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2009 – 2018
U.S. locations
12
States / cities
La Jolla, California • Orange, California • Tampa, Florida + 9 more
Source: ClinicalTrials.gov public record
Updated Dec 22, 2020 · Synced Oct 5, 2026, 7:42 PM 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 12, 2022 · Synced Oct 5, 2026, 7:42 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 5, 2026, 7:42 PM 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 7, 2015 · Synced Oct 5, 2026, 7:42 PM EDT
Completed Phase 3 Interventional Results available

Study to Evaluate the Safety and Efficacy of Phenoptin™ in Subjects With Phenylketonuria Who Have Elevated Phenylalanine Levels

NCT00104247
View directory record Official record
Conditions
Phenylketonurias
Interventions
sapropterin dihydrochloride, 6R-BH4, tetrahydrobiopterin
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
8 Years and older
Enrollment
89 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2005 – 2006
U.S. locations
13
States / cities
Los Angeles, California • Oakland, California • New Haven, Connecticut + 10 more
Source: ClinicalTrials.gov public record
Updated Jul 23, 2014 · Synced Oct 5, 2026, 7:42 PM EDT
Completed Phase 2 Interventional Results available

Endothelial Facilitation in Alzheimer's Disease

NCT01439555
View directory record Official record
Conditions
Alzheimer's Disease
Interventions
Simvastatin, L-Arginine, Tetrahydrobiopterin
Drug
Lead sponsor
University of Massachusetts, Worcester
Other
Eligibility
55 Years to 85 Years
Enrollment
11 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2011 – 2017
U.S. locations
1
States / cities
Worcester, Massachusetts
Source: ClinicalTrials.gov public record
Updated Jul 30, 2019 · Synced Oct 5, 2026, 7:42 PM EDT
Approved For Marketing No phase listed Expanded access

Sapropterin Expanded Access Program

NCT00484991
View directory record Official record
Conditions
Phenylketonuria
Interventions
Sapropterin dihydrochloride
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
9 Years and older
U.S. locations
36
States / cities
Los Angeles, California • Orange, California • San Diego, California + 33 more
Source: ClinicalTrials.gov public record
Updated Apr 15, 2008 · Synced Oct 5, 2026, 7:42 PM EDT