{
  "api_version": "1",
  "request": {
    "url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=6R-BH4+placebo",
    "query": {
      "intervention": "6R-BH4 placebo"
    },
    "page_size": 10
  },
  "pagination": {
    "page": 1,
    "page_size": 10,
    "total_count": 13,
    "total_pages": 2,
    "next_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=6R-BH4+placebo&page=2&page_size=10",
    "previous_page_url": null
  },
  "source": "remote",
  "last_synced_at": "2026-09-24T14:37:47.862Z",
  "attribution": "Data derived from public ClinicalTrials.gov records. The official record at https://clinicaltrials.gov/ remains the source of truth for current availability, contacts, and full study details.",
  "notes": [
    "This endpoint exposes only public summary fields — no participant contact emails, phone numbers, or scraped investigator contact details.",
    "For contact information and full protocol detail, follow each trial's `official_url` to the ClinicalTrials.gov record.",
    "This API is a navigational aid. It does not provide medical advice, eligibility determinations, or compensation guarantees."
  ],
  "trials": [
    {
      "nct_id": "NCT00325962",
      "title": "A Study of the Effects of 6R-BH4 on Blood Pressure in Subjects With Poorly Controlled Systemic Hypertension",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Hypertension"
      ],
      "interventions": [
        {
          "name": "6R-BH4 (sapropterin dihydrochloride)",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "BioMarin Pharmaceutical",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 84,
      "start_date": "2006-05",
      "completion_date": "2008-12",
      "has_results": false,
      "last_update_posted_date": "2009-07-21",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 24,
      "location_summary": "Hoover, Alabama • Huntsville, Alabama • Mobile, Alabama + 21 more",
      "locations": [
        {
          "city": "Hoover",
          "state": "Alabama"
        },
        {
          "city": "Huntsville",
          "state": "Alabama"
        },
        {
          "city": "Mobile",
          "state": "Alabama"
        },
        {
          "city": "Muscle Shoals",
          "state": "Alabama"
        },
        {
          "city": "Gilbert",
          "state": "Arizona"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00325962"
    },
    {
      "nct_id": "NCT03136029",
      "title": "Exercise and NO in HFrEF",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "EARLY_PHASE1"
      ],
      "conditions": [
        "Heart Failure With Reduced Ejection Fraction"
      ],
      "interventions": [
        {
          "name": "Antioxidant",
          "type": "DIETARY_SUPPLEMENT"
        },
        {
          "name": "Tetrahydrobiopterin (BH4)",
          "type": "DIETARY_SUPPLEMENT"
        },
        {
          "name": "Exercise training",
          "type": "OTHER"
        }
      ],
      "intervention_types": [
        "DIETARY_SUPPLEMENT",
        "OTHER"
      ],
      "sponsor": "VA Office of Research and Development",
      "sponsor_class": "FED",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 68,
      "start_date": "2018-06-01",
      "completion_date": "2025-07-31",
      "has_results": false,
      "last_update_posted_date": "2025-08-06",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 1,
      "location_summary": "Salt Lake City, Utah",
      "locations": [
        {
          "city": "Salt Lake City",
          "state": "Utah"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03136029"
    },
    {
      "nct_id": "NCT02042196",
      "title": "Sex Hormones and Atherosclerosis Prevention in Perimenopausal Women",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "EARLY_PHASE1"
      ],
      "conditions": [
        "Menopause",
        "Aging"
      ],
      "interventions": [
        {
          "name": "KUVAN",
          "type": "DRUG"
        },
        {
          "name": "Placebo",
          "type": "DRUG"
        },
        {
          "name": "Cetrotide",
          "type": "DRUG"
        },
        {
          "name": "Climara",
          "type": "DRUG"
        },
        {
          "name": "Placebo transdermal patch",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "University of Colorado, Denver",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "70 Years",
        "sex": "FEMALE",
        "summary": "18 Years to 70 Years · Female only"
      },
      "enrollment_count": 100,
      "start_date": "2013-12",
      "completion_date": "2016-05-02",
      "has_results": false,
      "last_update_posted_date": "2019-07-11",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 1,
      "location_summary": "Aurora, Colorado",
      "locations": [
        {
          "city": "Aurora",
          "state": "Colorado"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT02042196"
    },
    {
      "nct_id": "NCT06312748",
      "title": "Novel Approaches for Improving Vascular Function in Veterans With HFpEF",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Heart Failure With Preserved Ejection Fraction",
        "Inflammation"
      ],
      "interventions": [
        {
          "name": "L-Citrulline",
          "type": "DRUG"
        },
        {
          "name": "Placebo for L-Citrulline",
          "type": "DRUG"
        },
        {
          "name": "BH4",
          "type": "DRUG"
        },
        {
          "name": "Placebo for BH4",
          "type": "DRUG"
        },
        {
          "name": "Atorvastatin",
          "type": "DRUG"
        },
        {
          "name": "Placebo for Atorvastatin",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "VA Office of Research and Development",
      "sponsor_class": "FED",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 90,
      "start_date": "2021-05-19",
      "completion_date": "2030-09-30",
      "has_results": false,
      "last_update_posted_date": "2026-04-23",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 1,
      "location_summary": "Salt Lake City, Utah",
      "locations": [
        {
          "city": "Salt Lake City",
          "state": "Utah"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06312748"
    },
    {
      "nct_id": "NCT00104247",
      "title": "Study to Evaluate the Safety and Efficacy of Phenoptin™ in Subjects With Phenylketonuria Who Have Elevated Phenylalanine Levels",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Phenylketonurias"
      ],
      "interventions": [
        {
          "name": "sapropterin dihydrochloride, 6R-BH4, tetrahydrobiopterin",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "BioMarin Pharmaceutical",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "8 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "8 Years and older"
      },
      "enrollment_count": 89,
      "start_date": "2005-03",
      "completion_date": "2006-02",
      "has_results": true,
      "last_update_posted_date": "2014-07-23",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 13,
      "location_summary": "Los Angeles, California • Oakland, California • New Haven, Connecticut + 10 more",
      "locations": [
        {
          "city": "Los Angeles",
          "state": "California"
        },
        {
          "city": "Oakland",
          "state": "California"
        },
        {
          "city": "New Haven",
          "state": "Connecticut"
        },
        {
          "city": "Chicago",
          "state": "Illinois"
        },
        {
          "city": "Boston",
          "state": "Massachusetts"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00104247"
    },
    {
      "nct_id": "NCT00244218",
      "title": "Response to Phenylketonuria to Tetrahydrobiopterin (BH4)",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Phenylketonuria"
      ],
      "interventions": [
        {
          "name": "tetrahydrobiopterin (BH4)",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "The University of Texas Medical Branch, Galveston",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "10 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "10 Years and older"
      },
      "enrollment_count": 57,
      "start_date": "2005-04",
      "completion_date": "2015-01",
      "has_results": false,
      "last_update_posted_date": "2021-09-21",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 1,
      "location_summary": "Galveston, Texas",
      "locations": [
        {
          "city": "Galveston",
          "state": "Texas"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00244218"
    },
    {
      "nct_id": "NCT01114737",
      "title": "Safety and Therapeutic Effects of Sapropterin Dihydrochloride on Neuropsychiatric Symptoms in Phenylketonuria (PKU) Patients",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Phenylketonuria"
      ],
      "interventions": [
        {
          "name": "Sapropterin dihydrochloride",
          "type": "DRUG"
        },
        {
          "name": "Placebo",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "BioMarin Pharmaceutical",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "8 Years",
        "maximum_age": "65 Years",
        "sex": "ALL",
        "summary": "8 Years to 65 Years"
      },
      "enrollment_count": 206,
      "start_date": "2010-08",
      "completion_date": "2013-03",
      "has_results": true,
      "last_update_posted_date": "2016-02-01",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 26,
      "location_summary": "La Jolla, California • Los Angeles, California • Palo Alto, California + 23 more",
      "locations": [
        {
          "city": "La Jolla",
          "state": "California"
        },
        {
          "city": "Los Angeles",
          "state": "California"
        },
        {
          "city": "Palo Alto",
          "state": "California"
        },
        {
          "city": "San Francisco",
          "state": "California"
        },
        {
          "city": "Aurora",
          "state": "Colorado"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT01114737"
    },
    {
      "nct_id": "NCT00802893",
      "title": "Oral 6R-BH4 for the Treatment of Isolated Systolic Hypertension and Endothelial Dysfunction",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Isolated Systolic Hypertension",
        "Endothelial Dysfunction"
      ],
      "interventions": [
        {
          "name": "6R-BH4",
          "type": "DRUG"
        },
        {
          "name": "Placebo",
          "type": "OTHER"
        }
      ],
      "intervention_types": [
        "DRUG",
        "OTHER"
      ],
      "sponsor": "Johns Hopkins University",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "40 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "40 Years and older"
      },
      "enrollment_count": 3,
      "start_date": "2008-12",
      "completion_date": "2009-05",
      "has_results": true,
      "last_update_posted_date": "2017-08-21",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 1,
      "location_summary": "Baltimore, Maryland",
      "locations": [
        {
          "city": "Baltimore",
          "state": "Maryland"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00802893"
    },
    {
      "nct_id": "NCT04014712",
      "title": "O2 Transport and Utilization in Health and Lung Disease",
      "overall_status": "WITHDRAWN",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "COPD",
        "Tetrahydrobiopterin Deficiency",
        "Oxidative Stress"
      ],
      "interventions": [
        {
          "name": "Tetrahydrobiopterin",
          "type": "DRUG"
        },
        {
          "name": "Placebo oral tablet",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "University of Massachusetts, Amherst",
      "sponsor_class": "OTHER",
      "healthy_volunteers": true,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "85 Years",
        "sex": "ALL",
        "summary": "18 Years to 85 Years"
      },
      "enrollment_count": 0,
      "start_date": "2021-04",
      "completion_date": "2022-08",
      "has_results": false,
      "last_update_posted_date": "2023-12-19",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 1,
      "location_summary": "Amherst, Massachusetts",
      "locations": [
        {
          "city": "Amherst",
          "state": "Massachusetts"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04014712"
    },
    {
      "nct_id": "NCT00403494",
      "title": "A Phase 2 Study of the Effects of Sapropterin Dihydrochloride on Symptomatic Peripheral Arterial Disease",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Intermittent Claudication"
      ],
      "interventions": [
        {
          "name": "Placebo",
          "type": "OTHER"
        },
        {
          "name": "Sapropterin Dihydrochloride",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "OTHER",
        "DRUG"
      ],
      "sponsor": "BioMarin Pharmaceutical",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "40 Years",
        "maximum_age": "80 Years",
        "sex": "ALL",
        "summary": "40 Years to 80 Years"
      },
      "enrollment_count": 190,
      "start_date": "2006-12",
      "completion_date": "2009-01",
      "has_results": true,
      "last_update_posted_date": "2021-01-07",
      "last_synced_at": "2026-09-24T14:37:47.862Z",
      "location_count": 17,
      "location_summary": "Scottsdale, Arizona • Sacramento, California • San Diego, California + 14 more",
      "locations": [
        {
          "city": "Scottsdale",
          "state": "Arizona"
        },
        {
          "city": "Sacramento",
          "state": "California"
        },
        {
          "city": "San Diego",
          "state": "California"
        },
        {
          "city": "Santa Ana",
          "state": "California"
        },
        {
          "city": "Santa Rosa",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00403494"
    }
  ]
}