{
  "api_version": "1",
  "request": {
    "url": "https://clinicaltrialsfind.com/api/v1/search.json?condition=Estrogen+Receptor+Antagonist",
    "query": {
      "condition": "Estrogen Receptor Antagonist"
    },
    "page_size": 10
  },
  "pagination": {
    "page": 1,
    "page_size": 10,
    "total_count": 25,
    "total_pages": 3,
    "next_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?condition=Estrogen+Receptor+Antagonist&page=2&page_size=10",
    "previous_page_url": null
  },
  "source": "remote",
  "last_synced_at": "2026-07-24T12:27:29.229Z",
  "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": "NCT00826839",
      "title": "Oral Microdose Lupron Versus Luteal Estradiol Trial in Poor Responder In Vitro Fertilization (IVF) Patients",
      "overall_status": "WITHDRAWN",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Infertility"
      ],
      "interventions": [
        {
          "name": "Oral contraceptive pill and microdose lupron",
          "type": "DRUG"
        },
        {
          "name": "E2 patch/antagonist",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Weill Medical College of Cornell University",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "50 Years",
        "sex": "FEMALE",
        "summary": "18 Years to 50 Years · Female only"
      },
      "enrollment_count": 0,
      "start_date": "2009-01",
      "completion_date": "2012-01",
      "has_results": false,
      "last_update_posted_date": "2013-06-25",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 1,
      "location_summary": "New York, New York",
      "locations": [
        {
          "city": "New York",
          "state": "New York"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00826839"
    },
    {
      "nct_id": "NCT02513329",
      "title": "Stellate Ganglion Block (SGB) For Women for Breast Cancer",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Hot Flushes",
        "Hot Flashes"
      ],
      "interventions": [
        {
          "name": "Bupivicaine",
          "type": "DRUG"
        },
        {
          "name": "Saline",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Northwestern University",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "30 Years",
        "maximum_age": "70 Years",
        "sex": "FEMALE",
        "summary": "30 Years to 70 Years · Female only"
      },
      "enrollment_count": 37,
      "start_date": "2015-07",
      "completion_date": "2020-01",
      "has_results": true,
      "last_update_posted_date": "2023-06-05",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 1,
      "location_summary": "Chicago, Illinois",
      "locations": [
        {
          "city": "Chicago",
          "state": "Illinois"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT02513329"
    },
    {
      "nct_id": "NCT00050141",
      "title": "Study of Letrozole Plus Tipifarnib or Placebo in the Treatment of Advanced Breast Cancer",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Breast Cancer"
      ],
      "interventions": [
        {
          "name": "ZARNESTRA, tipifarnib, R115777",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Johnson & Johnson Pharmaceutical Research & Development, L.L.C.",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "50 Years",
        "maximum_age": null,
        "sex": "FEMALE",
        "summary": "50 Years and older · Female only"
      },
      "enrollment_count": 121,
      "start_date": "2002-09",
      "completion_date": "2008-01",
      "has_results": false,
      "last_update_posted_date": "2013-02-01",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 6,
      "location_summary": "Miami, Florida • Chicago, Illinois • Durham, North Carolina + 3 more",
      "locations": [
        {
          "city": "Miami",
          "state": "Florida"
        },
        {
          "city": "Chicago",
          "state": "Illinois"
        },
        {
          "city": "Durham",
          "state": "North Carolina"
        },
        {
          "city": "Cleveland",
          "state": "Ohio"
        },
        {
          "city": "Fort Worth",
          "state": "Texas"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00050141"
    },
    {
      "nct_id": "NCT03566485",
      "title": "Atezolizumab and Cobimetinib or Idasanutlin in Participants With Stage IV or Unresectable Recurrent Estrogen Receptor Positive Breast Cancer",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Stage III Breast Cancer",
        "Stage IIIA Breast Cancer",
        "Stage IIIB Breast Cancer",
        "Stage IIIC Breast Cancer",
        "Stage IV Breast Cancer",
        "Estrogen Receptor-positive",
        "HER2/Neu Negative"
      ],
      "interventions": [
        {
          "name": "Atezolizumab",
          "type": "DRUG"
        },
        {
          "name": "Cobimetinib",
          "type": "DRUG"
        },
        {
          "name": "Idasanutlin",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Vanderbilt-Ingram Cancer Center",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "FEMALE",
        "summary": "18 Years and older · Female only"
      },
      "enrollment_count": 12,
      "start_date": "2018-07-10",
      "completion_date": "2020-12-10",
      "has_results": true,
      "last_update_posted_date": "2021-08-11",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 1,
      "location_summary": "Nashville, Tennessee",
      "locations": [
        {
          "city": "Nashville",
          "state": "Tennessee"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03566485"
    },
    {
      "nct_id": "NCT01071564",
      "title": "RO4929097 and Vismodegib in Treating Patients With Breast Cancer That is Metastatic or Cannot Be Removed By Surgery",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "Estrogen Receptor Negative",
        "HER2/Neu Negative",
        "Progesterone Receptor Negative",
        "Recurrent Breast Carcinoma",
        "Stage IIIB Breast Cancer",
        "Stage IIIC Breast Cancer",
        "Stage IV Breast Cancer",
        "Triple-Negative Breast Carcinoma"
      ],
      "interventions": [
        {
          "name": "Gamma-Secretase Inhibitor RO4929097",
          "type": "DRUG"
        },
        {
          "name": "Laboratory Biomarker Analysis",
          "type": "OTHER"
        },
        {
          "name": "Pharmacogenomic Study",
          "type": "OTHER"
        },
        {
          "name": "Pharmacological Study",
          "type": "OTHER"
        },
        {
          "name": "Vismodegib",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG",
        "OTHER"
      ],
      "sponsor": "National Cancer Institute (NCI)",
      "sponsor_class": "NIH",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 13,
      "start_date": "2009-11",
      "completion_date": "2014-06",
      "has_results": false,
      "last_update_posted_date": "2015-04-15",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 3,
      "location_summary": "Baltimore, Maryland • Ann Arbor, Michigan • Detroit, Michigan",
      "locations": [
        {
          "city": "Baltimore",
          "state": "Maryland"
        },
        {
          "city": "Ann Arbor",
          "state": "Michigan"
        },
        {
          "city": "Detroit",
          "state": "Michigan"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT01071564"
    },
    {
      "nct_id": "NCT04711252",
      "title": "A Comparative Study of AZD9833 Plus Palbociclib Versus Anastrozole Plus Palbociclib in Patients With ER-Positive HER2 Negative Breast Cancer Who Have Not Received Any Systemic Treatment for Advanced Disease",
      "overall_status": "ACTIVE_NOT_RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "ER-Positive HER2-Negative Breast Cancer"
      ],
      "interventions": [
        {
          "name": "AZD9833",
          "type": "DRUG"
        },
        {
          "name": "Anastrozole",
          "type": "DRUG"
        },
        {
          "name": "Anastrozole placebo",
          "type": "DRUG"
        },
        {
          "name": "AZD9833 placebo",
          "type": "DRUG"
        },
        {
          "name": "Palbociclib",
          "type": "DRUG"
        },
        {
          "name": "Luteinizing hormone-releasing hormone (LHRH) agonist",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "AstraZeneca",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "130 Years",
        "sex": "ALL",
        "summary": "18 Years to 130 Years"
      },
      "enrollment_count": 1370,
      "start_date": "2021-01-28",
      "completion_date": "2029-02-01",
      "has_results": false,
      "last_update_posted_date": "2025-10-14",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 30,
      "location_summary": "Mobile, Alabama • Springdale, Arkansas • Harbor City, California + 25 more",
      "locations": [
        {
          "city": "Mobile",
          "state": "Alabama"
        },
        {
          "city": "Springdale",
          "state": "Arkansas"
        },
        {
          "city": "Harbor City",
          "state": "California"
        },
        {
          "city": "Solvang",
          "state": "California"
        },
        {
          "city": "Lone Tree",
          "state": "Colorado"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04711252"
    },
    {
      "nct_id": "NCT04964934",
      "title": "Phase III Study to Assess AZD9833+ CDK4/6 Inhibitor in HR+/HER2-MBC With Detectable ESR1m Before Progression (SERENA-6)",
      "overall_status": "ACTIVE_NOT_RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "ER-Positive HER2-Negative Breast Cancer"
      ],
      "interventions": [
        {
          "name": "AZD9833",
          "type": "DRUG"
        },
        {
          "name": "AZD9833 Placebo",
          "type": "DRUG"
        },
        {
          "name": "Anastrozole",
          "type": "DRUG"
        },
        {
          "name": "Anastrozole placebo",
          "type": "DRUG"
        },
        {
          "name": "Letrozole",
          "type": "DRUG"
        },
        {
          "name": "Letrozole placebo",
          "type": "DRUG"
        },
        {
          "name": "Palbociclib",
          "type": "DRUG"
        },
        {
          "name": "Abemaciclib",
          "type": "DRUG"
        },
        {
          "name": "Luteinizing hormone-releasing hormone (LHRH) agonist",
          "type": "DRUG"
        },
        {
          "name": "Ribociclib",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "AstraZeneca",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "130 Years",
        "sex": "ALL",
        "summary": "18 Years to 130 Years"
      },
      "enrollment_count": 315,
      "start_date": "2021-06-30",
      "completion_date": "2028-09-01",
      "has_results": false,
      "last_update_posted_date": "2026-07-14",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 64,
      "location_summary": "Phoenix, Arizona • Hot Springs, Arkansas • Little Rock, Arkansas + 56 more",
      "locations": [
        {
          "city": "Phoenix",
          "state": "Arizona"
        },
        {
          "city": "Hot Springs",
          "state": "Arkansas"
        },
        {
          "city": "Little Rock",
          "state": "Arkansas"
        },
        {
          "city": "Long Beach",
          "state": "California"
        },
        {
          "city": "San Diego",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04964934"
    },
    {
      "nct_id": "NCT03250676",
      "title": "Trial of H3B-6545, in Women With Locally Advanced or Metastatic Estrogen Receptor-positive, HER2 Negative Breast Cancer",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Breast Neoplasms",
        "Breast Cancer",
        "Estrogen-receptor Positive Breast Cancer",
        "Cancer, Breast",
        "Breast Cancer Female",
        "Breast Adenocarcinoma",
        "Estrogen Receptor Positive Tumor",
        "ER Positive"
      ],
      "interventions": [
        {
          "name": "H3B-6545",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Eisai Inc.",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "FEMALE",
        "summary": "18 Years and older · Female only"
      },
      "enrollment_count": 151,
      "start_date": "2017-08-23",
      "completion_date": "2023-10-26",
      "has_results": true,
      "last_update_posted_date": "2025-02-25",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 23,
      "location_summary": "Goodyear, Arizona • Los Angeles, California • San Francisco, California + 18 more",
      "locations": [
        {
          "city": "Goodyear",
          "state": "Arizona"
        },
        {
          "city": "Los Angeles",
          "state": "California"
        },
        {
          "city": "San Francisco",
          "state": "California"
        },
        {
          "city": "Aurora",
          "state": "Colorado"
        },
        {
          "city": "Fort Lauderdale",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03250676"
    },
    {
      "nct_id": "NCT06993844",
      "title": "Phase 1/2 Study of ETX-636 in Participants With Advanced Solid Tumors",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Advanced Solid Tumors",
        "Advanced Breast Cancer"
      ],
      "interventions": [
        {
          "name": "ETX-636 dose escalation",
          "type": "DRUG"
        },
        {
          "name": "ETX-636 dose escalation in combination with fulvestrant",
          "type": "DRUG"
        },
        {
          "name": "ETX-636 dose expansion in combination with fulvestrant",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Ensem Therapeutics",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 233,
      "start_date": "2025-06-10",
      "completion_date": "2027-12-30",
      "has_results": false,
      "last_update_posted_date": "2026-06-23",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 10,
      "location_summary": "Newport Beach, California • San Francisco, California • New Haven, Connecticut + 6 more",
      "locations": [
        {
          "city": "Newport Beach",
          "state": "California"
        },
        {
          "city": "San Francisco",
          "state": "California"
        },
        {
          "city": "New Haven",
          "state": "Connecticut"
        },
        {
          "city": "Boston",
          "state": "Massachusetts"
        },
        {
          "city": "Boston",
          "state": "Massachusetts"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06993844"
    },
    {
      "nct_id": "NCT02911844",
      "title": "Estrogen Receptor Antagonist in Patients With Pulmonary Arterial Hypertension",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Pulmonary Arterial Hypertension"
      ],
      "interventions": [
        {
          "name": "Fulvestrant",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "University of Pennsylvania",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "FEMALE",
        "summary": "18 Years and older · Female only"
      },
      "enrollment_count": 5,
      "start_date": "2017-04-10",
      "completion_date": "2018-12-05",
      "has_results": true,
      "last_update_posted_date": "2019-12-09",
      "last_synced_at": "2026-07-24T12:27:29.229Z",
      "location_count": 1,
      "location_summary": "Philadelphia, Pennsylvania",
      "locations": [
        {
          "city": "Philadelphia",
          "state": "Pennsylvania"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT02911844"
    }
  ]
}