Independent directory Public ClinicalTrials.gov records United States
Clinical Trials Finder
Objective public record navigation
Search Results

Search by objective public record fields.

Search by query text, NCT ID, condition, intervention, sponsor, city, state, recruitment status, phase, study type, healthy volunteer eligibility, sex, or age. Results are retrieved from ClinicalTrials.gov and synchronized into the directory. Search pages remain noindex by default.

Clear filters
ClinicalTrials.gov public records Last synced Sep 29, 2026, 2:13 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 24 matching trials from the live ClinicalTrials.gov search.
Local D1 index available.
Filters: Intervention: Tetrahydrobiopterin Clear all
Completed Phase 1 Interventional Accepts healthy volunteers

A Phase 1 Study to Evaluate Effects of Sapropterin Dihydrochloride on QTc Intervals in Healthy Adult Subjects

NCT00789568
View directory record Official record
Conditions
Phenylketonuria
Interventions
sapropterin dihydrochloride, Moxifloxacin, Moxifloxacin placebo
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
18 Years to 50 Years
Enrollment
56 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2008 – 2009
U.S. locations
1
States / cities
Fargo, North Dakota
Source: ClinicalTrials.gov public record
Updated Jul 22, 2021 · Synced Sep 29, 2026, 2:13 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 10, 2019 · Synced Sep 29, 2026, 2:13 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 14, 2008 · Synced Sep 29, 2026, 2:13 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 1, 2018 · Synced Sep 29, 2026, 2:13 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 14, 2026 · Synced Sep 29, 2026, 2:13 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 Mar 31, 2025 · Synced Sep 29, 2026, 2:13 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 17, 2013 · Synced Sep 29, 2026, 2:13 PM EDT
Completed Phase 3 Interventional Results available

Study of Phenoptin in Subjects With Phenylketonuria Who Participated in Protocols PKU-004 or PKU-006

NCT00332189
View directory record Official record
Conditions
Phenylketonuria
Interventions
sapropterin dihydrochloride
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
4 Years and older
Enrollment
111 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2006 – 2009
U.S. locations
14
States / cities
Los Angeles, California • Sacramento, California • San Jose, California + 11 more
Source: ClinicalTrials.gov public record
Updated Nov 15, 2012 · Synced Sep 29, 2026, 2:13 PM EDT
Completed Phase 2 Interventional

A Study of the Effects of 6R-BH4 on Blood Pressure in Subjects With Poorly Controlled Systemic Hypertension

NCT00325962
View directory record Official record
Conditions
Hypertension
Interventions
6R-BH4 (sapropterin dihydrochloride)
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
18 Years and older
Enrollment
84 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2006 – 2008
U.S. locations
24
States / cities
Hoover, Alabama • Huntsville, Alabama • Mobile, Alabama + 21 more
Source: ClinicalTrials.gov public record
Updated Jul 20, 2009 · Synced Sep 29, 2026, 2:13 PM EDT
Terminated Not applicable Interventional Accepts healthy volunteers Results available

A Pilot Study on Diurnal Variation

NCT01806051
View directory record Official record
Conditions
Phenylketonuria (PKU)
Interventions
Kuvan
Drug
Lead sponsor
Dr. Linda Randolph
Other
Eligibility
4 Years and older
Enrollment
6 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2013 – 2014
U.S. locations
1
States / cities
Los Angeles, California
Source: ClinicalTrials.gov public record
Updated Apr 19, 2016 · Synced Sep 29, 2026, 2:13 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 13, 2023 · Synced Sep 29, 2026, 2:13 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 24, 2021 · Synced Sep 29, 2026, 2:13 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 24, 2026 · Synced Sep 29, 2026, 2:13 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 17, 2016 · Synced Sep 29, 2026, 2:13 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 17, 2013 · Synced Sep 29, 2026, 2:13 PM EDT
Completed No phase listed Observational Accepts healthy volunteers

Determination of Variances in Exhaled Nitric Oxide Output in Normal Healthy Male Volunteers Consuming High and Low Nitrate/Nitrite Diets

NCT00027157
View directory record Official record
Conditions
Healthy
Interventions
Not listed
Lead sponsor
National Heart, Lung, and Blood Institute (NHLBI)
NIH
Eligibility
Male only
Enrollment
18 participants
Healthy volunteers
Accepts healthy volunteers
Timeline
2000 – 2003
U.S. locations
1
States / cities
Bethesda, Maryland
Source: ClinicalTrials.gov public record
Updated Mar 3, 2008 · Synced Sep 29, 2026, 2:13 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 29, 2019 · Synced Sep 29, 2026, 2:13 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 19, 2009 · Synced Sep 29, 2026, 2:13 PM EDT
Completed Phase 2 Interventional Results available

A Phase 2, Pharmacokinetic (PK) Study of 6R-BH4 Alone or 6R-BH4 With Vitamin C in Subjects With Endothelial Dysfunction

NCT00532844
View directory record Official record
Conditions
Endothelial Dysfunction
Interventions
Sapropterin Dihydrochloride, Sapropterin Dihydrochloride and Vitamin C
Drug
Lead sponsor
BioMarin Pharmaceutical
Industry
Eligibility
18 Years to 75 Years
Enrollment
52 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2007 – 2009
U.S. locations
1
States / cities
Hackensack, New Jersey
Source: ClinicalTrials.gov public record
Updated May 16, 2021 · Synced Sep 29, 2026, 2:13 PM EDT
Completed Phase 4 Interventional Results available

Effects of Kuvan on Melatonin Secretion

NCT01617070
View directory record Official record
Conditions
Phenylketonuria (PKU)
Interventions
Kuvan, Large Neutral Amino Acid Therapy
Drug · Dietary Supplement
Lead sponsor
University of Southern California
Other
Eligibility
18 Years and older
Enrollment
10 participants
Healthy volunteers
Healthy volunteers not accepted
Timeline
2012 – 2014
U.S. locations
1
States / cities
Los Angeles, California
Source: ClinicalTrials.gov public record
Updated Nov 17, 2016 · Synced Sep 29, 2026, 2:13 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 1, 2019 · Synced Sep 29, 2026, 2:13 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 10, 2017 · Synced Sep 29, 2026, 2:13 PM EDT
Withdrawn Not applicable Interventional

Neuroimaging and Neurocognitive Assessment and Response to Sapropterin Dihydrochloride Treatment in Phenylketonuria

NCT01412437
View directory record Official record
Conditions
PKU
Interventions
diet, sapropterin dihydrochloride
Dietary Supplement · Drug
Lead sponsor
Children's National Research Institute
Other
Eligibility
18 Years to 40 Years
Healthy volunteers
Healthy volunteers not accepted
Timeline
2011 – 2012
U.S. locations
1
States / cities
Washington D.C., District of Columbia
Source: ClinicalTrials.gov public record
Updated Dec 16, 2014 · Synced Sep 29, 2026, 2:13 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 19, 2022 · Synced Sep 29, 2026, 2:13 PM EDT