{
  "api_version": "1",
  "request": {
    "url": "https://clinicaltrialsfind.com/api/v1/search.json?condition=ESR1+Gene+Mutation",
    "query": {
      "condition": "ESR1 Gene Mutation"
    },
    "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=ESR1+Gene+Mutation&page=2&page_size=10",
    "previous_page_url": null
  },
  "source": "remote",
  "last_synced_at": "2026-07-24T03:08:06.134Z",
  "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": "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": "2026-07-24T03:08:06.134Z",
      "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": "NCT04174352",
      "title": "FES Imaging to Optimize Tamoxifen for Metastatic Breast Cancer",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "EARLY_PHASE1"
      ],
      "conditions": [
        "ERα+ Breast Cancer",
        "ESR1 Gene Mutation"
      ],
      "interventions": [
        {
          "name": "Tamoxifen",
          "type": "DRUG"
        },
        {
          "name": "FES PET/CT",
          "type": "DIAGNOSTIC_TEST"
        }
      ],
      "intervention_types": [
        "DRUG",
        "DIAGNOSTIC_TEST"
      ],
      "sponsor": "University of Wisconsin, Madison",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "19 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "19 Years and older"
      },
      "enrollment_count": 12,
      "start_date": "2020-10-20",
      "completion_date": "2027-12",
      "has_results": false,
      "last_update_posted_date": "2026-07-21",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 2,
      "location_summary": "Madison, Wisconsin",
      "locations": [
        {
          "city": "Madison",
          "state": "Wisconsin"
        },
        {
          "city": "Madison",
          "state": "Wisconsin"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04174352"
    },
    {
      "nct_id": "NCT05868226",
      "title": "PRE-I-SPY Phase I/Ib Oncology Platform Program",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1"
      ],
      "conditions": [
        "HER2-positive Breast Cancer",
        "Metastatic Cancer",
        "Metastatic Breast Cancer",
        "Metastatic",
        "HER2-positive Metastatic Breast Cancer",
        "HER2 Mutation-Related Tumors",
        "HER-2 Protein Overexpression",
        "HER2-negative Breast Cancer",
        "Triple Negative Breast Cancer",
        "HR Positive",
        "Hormone Receptor-positive Breast Cancer",
        "Estrogen Receptor Positive Tumor",
        "Progesterone Receptor-positive Breast Cancer",
        "Hormone Receptor Negative Breast Carcinoma",
        "Solid Tumor",
        "Solid Tumor, Adult",
        "Solid Carcinoma",
        "HER2 Low Breast Cancer",
        "HER2 Low Breast Carcinoma",
        "ER Positive Breast Cancer",
        "PR-positive Breast Cancer"
      ],
      "interventions": [
        {
          "name": "ALX148",
          "type": "DRUG"
        },
        {
          "name": "Fam-Trastuzumab Deruxtecan-Nxki",
          "type": "DRUG"
        },
        {
          "name": "Zanidatamab",
          "type": "DRUG"
        },
        {
          "name": "Tucatinib",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "QuantumLeap Healthcare Collaborative",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 124,
      "start_date": "2023-02-15",
      "completion_date": "2029-12-30",
      "has_results": false,
      "last_update_posted_date": "2025-04-04",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 7,
      "location_summary": "Birmingham, Alabama • Tampa, Florida • Chicago, Illinois + 4 more",
      "locations": [
        {
          "city": "Birmingham",
          "state": "Alabama"
        },
        {
          "city": "Tampa",
          "state": "Florida"
        },
        {
          "city": "Chicago",
          "state": "Illinois"
        },
        {
          "city": "New Lenox",
          "state": "Illinois"
        },
        {
          "city": "Orland Park",
          "state": "Illinois"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05868226"
    },
    {
      "nct_id": "NCT05054374",
      "title": "A Study of Mirdametinib on Its Own or in Combination With Fulvestrant in People With Solid Tumor Cancer",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Breast Cancer",
        "Breast Cancer Stage IV",
        "HER2-negative Breast Cancer",
        "Solid Carcinoma",
        "MEK1 Gene Mutation",
        "MEK2 Gene Mutation",
        "Metastatic Breast Cancer"
      ],
      "interventions": [
        {
          "name": "Mirdametinib",
          "type": "DRUG"
        },
        {
          "name": "Fulvestrant",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Memorial Sloan Kettering Cancer Center",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 6,
      "start_date": "2021-09-14",
      "completion_date": "2023-10-26",
      "has_results": true,
      "last_update_posted_date": "2025-05-23",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 4,
      "location_summary": "Middletown, New Jersey • Commack, New York • Harrison, New York + 1 more",
      "locations": [
        {
          "city": "Middletown",
          "state": "New Jersey"
        },
        {
          "city": "Commack",
          "state": "New York"
        },
        {
          "city": "Harrison",
          "state": "New York"
        },
        {
          "city": "New York",
          "state": "New York"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05054374"
    },
    {
      "nct_id": "NCT05768139",
      "title": "First-in-Human Study of Tersolisib (STX-478) as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "Breast Cancer",
        "Solid Tumors, Adult"
      ],
      "interventions": [
        {
          "name": "STX-478",
          "type": "DRUG"
        },
        {
          "name": "Fulvestrant",
          "type": "DRUG"
        },
        {
          "name": "Ribociclib",
          "type": "DRUG"
        },
        {
          "name": "Palbociclib",
          "type": "DRUG"
        },
        {
          "name": "Letrozole",
          "type": "DRUG"
        },
        {
          "name": "Anastrozole",
          "type": "DRUG"
        },
        {
          "name": "Exemestane",
          "type": "DRUG"
        },
        {
          "name": "Tamoxifen",
          "type": "DRUG"
        },
        {
          "name": "Abemaciclib",
          "type": "DRUG"
        },
        {
          "name": "Imlunestrant",
          "type": "DRUG"
        },
        {
          "name": "Metformin",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Eli Lilly and Company",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 880,
      "start_date": "2023-04-17",
      "completion_date": "2030-07",
      "has_results": false,
      "last_update_posted_date": "2026-07-07",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 28,
      "location_summary": "Los Angeles, California • San Francisco, California • Aurora, Colorado + 22 more",
      "locations": [
        {
          "city": "Los Angeles",
          "state": "California"
        },
        {
          "city": "San Francisco",
          "state": "California"
        },
        {
          "city": "Aurora",
          "state": "Colorado"
        },
        {
          "city": "New Haven",
          "state": "Connecticut"
        },
        {
          "city": "Lake Mary",
          "state": "Florida"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05768139"
    },
    {
      "nct_id": "NCT06065748",
      "title": "A Study to Evaluate Efficacy and Safety of Giredestrant Compared With Fulvestrant (Plus a CDK4/6 Inhibitor), in Participants With ER-Positive, HER2-Negative Advanced Breast Cancer Resistant to Adjuvant Endocrine Therapy (pionERA Breast Cancer)",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Estrogen Receptor-Positive, HER2-Negative Advanced Breast Cancer"
      ],
      "interventions": [
        {
          "name": "Giredestrant",
          "type": "DRUG"
        },
        {
          "name": "Fulvestrant",
          "type": "DRUG"
        },
        {
          "name": "Abemaciclib",
          "type": "DRUG"
        },
        {
          "name": "Palbociclib",
          "type": "DRUG"
        },
        {
          "name": "Ribociclib",
          "type": "DRUG"
        },
        {
          "name": "LHRH Agonist",
          "type": "DRUG"
        },
        {
          "name": "FoundationOne Liquid CDx Assay (F1LCDx)",
          "type": "DIAGNOSTIC_TEST"
        }
      ],
      "intervention_types": [
        "DRUG",
        "DIAGNOSTIC_TEST"
      ],
      "sponsor": "Hoffmann-La Roche",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 1050,
      "start_date": "2023-12-11",
      "completion_date": "2029-02-12",
      "has_results": false,
      "last_update_posted_date": "2026-07-06",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 61,
      "location_summary": "Daphne, Alabama • Auburn, California • Glendale, California + 54 more",
      "locations": [
        {
          "city": "Daphne",
          "state": "Alabama"
        },
        {
          "city": "Auburn",
          "state": "California"
        },
        {
          "city": "Glendale",
          "state": "California"
        },
        {
          "city": "Greenbrae",
          "state": "California"
        },
        {
          "city": "Harbor City",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT06065748"
    },
    {
      "nct_id": "NCT00342498",
      "title": "Estrogen Receptor Gene Mutations",
      "overall_status": "COMPLETED",
      "study_type": "OBSERVATIONAL",
      "phases": [],
      "conditions": [
        "Mutations",
        "Hormones"
      ],
      "interventions": [],
      "intervention_types": [],
      "sponsor": "National Institute of Environmental Health Sciences (NIEHS)",
      "sponsor_class": "NIH",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 0,
      "start_date": "1994-01-12",
      "completion_date": "2008-06-17",
      "has_results": false,
      "last_update_posted_date": "2017-07-02",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 2,
      "location_summary": "Research Triangle Park, North Carolina • Cincinnati, Ohio",
      "locations": [
        {
          "city": "Research Triangle Park",
          "state": "North Carolina"
        },
        {
          "city": "Cincinnati",
          "state": "Ohio"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00342498"
    },
    {
      "nct_id": "NCT07558733",
      "title": "Sapanisertib and Serabelisib (PIKTOR) in Various Combinations in Patients With HR+/HER2- Advanced/Metastatic Breast Cancer",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE1",
        "PHASE2"
      ],
      "conditions": [
        "HR+ HER2- Breast Cancer"
      ],
      "interventions": [
        {
          "name": "Serabelisib",
          "type": "DRUG"
        },
        {
          "name": "Sapanisertib",
          "type": "DRUG"
        },
        {
          "name": "Fulvestrant",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Faeth Therapeutics",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 32,
      "start_date": "2026-04-22",
      "completion_date": "2033-05",
      "has_results": false,
      "last_update_posted_date": "2026-07-02",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 7,
      "location_summary": "Los Angeles, California • Lone Tree, Colorado • Springfield, Oregon + 3 more",
      "locations": [
        {
          "city": "Los Angeles",
          "state": "California"
        },
        {
          "city": "Lone Tree",
          "state": "Colorado"
        },
        {
          "city": "Springfield",
          "state": "Oregon"
        },
        {
          "city": "Nashville",
          "state": "Tennessee"
        },
        {
          "city": "Austin",
          "state": "Texas"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT07558733"
    },
    {
      "nct_id": "NCT05183828",
      "title": "Effect of HSD3B1 (1245C) Gene Mutation on Treatment of Stage I-III Breast Cancer",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE4"
      ],
      "conditions": [
        "Anatomic Stage I Breast Cancer AJCC v8",
        "Anatomic Stage II Breast Cancer AJCC v8",
        "Anatomic Stage III Breast Cancer AJCC v8",
        "Breast Adenocarcinoma",
        "Invasive Breast Carcinoma of No Special Type"
      ],
      "interventions": [
        {
          "name": "Biospecimen Collection",
          "type": "PROCEDURE"
        },
        {
          "name": "Letrozole",
          "type": "DRUG"
        },
        {
          "name": "Questionnaire Administration",
          "type": "OTHER"
        }
      ],
      "intervention_types": [
        "PROCEDURE",
        "DRUG",
        "OTHER"
      ],
      "sponsor": "University of Washington",
      "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": 62,
      "start_date": "2022-01-23",
      "completion_date": "2026-05-13",
      "has_results": false,
      "last_update_posted_date": "2026-06-04",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 1,
      "location_summary": "Seattle, Washington",
      "locations": [
        {
          "city": "Seattle",
          "state": "Washington"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05183828"
    },
    {
      "nct_id": "NCT07499999",
      "title": "Randomized Double-Blind Phase II Trial of Baby Exemestane Versus Baby Tamoxifen in Post-Menopausal Women at High Risk for Breast Cancer",
      "overall_status": "NOT_YET_RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Breast Cancer",
        "Ductal Carcinoma",
        "Estrogen-receptor-positive Breast Cancer",
        "Atypical Lobular Hyperplasia",
        "BRCA2 Mutation",
        "CHEK2 Gene Mutation",
        "Ataxia Telangiectasia Mutated Gene Mutation"
      ],
      "interventions": [
        {
          "name": "Exemestane",
          "type": "DRUG"
        },
        {
          "name": "Tamoxifen",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Dana-Farber Cancer Institute",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": null,
        "maximum_age": null,
        "sex": "FEMALE",
        "summary": "Female only"
      },
      "enrollment_count": 140,
      "start_date": "2026-09-09",
      "completion_date": "2028-08-31",
      "has_results": false,
      "last_update_posted_date": "2026-03-30",
      "last_synced_at": "2026-07-24T03:08:06.134Z",
      "location_count": 2,
      "location_summary": "Boston, Massachusetts",
      "locations": [
        {
          "city": "Boston",
          "state": "Massachusetts"
        },
        {
          "city": "Boston",
          "state": "Massachusetts"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT07499999"
    }
  ]
}