{ "api_version": "1", "request": { "url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=Estrogen+Receptor+Antagonist&page=3", "query": { "intervention": "Estrogen Receptor Antagonist", "page": 3 }, "page_size": 10 }, "pagination": { "page": 3, "page_size": 10, "total_count": 93, "total_pages": 10, "next_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=Estrogen+Receptor+Antagonist&page=4&page_size=10", "previous_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=Estrogen+Receptor+Antagonist&page=2&page_size=10" }, "source": "remote", "last_synced_at": "2026-10-05T05:48:00.078Z", "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": "NCT03241810", "title": "Phase 2 Trial of Seribantumab Plus Fulvestrant in Postmenopausal Women With Metastatic Breast Cancer", "overall_status": "TERMINATED", "study_type": "INTERVENTIONAL", "phases": [ "PHASE2" ], "conditions": [ "Metastatic Breast Cancer" ], "interventions": [ { "name": "Seribantumab", "type": "DRUG" }, { "name": "Fulvestrant", "type": "DRUG" }, { "name": "Placebo", "type": "DRUG" } ], "intervention_types": [ "DRUG" ], "sponsor": "Elevation Oncology", "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": 22, "start_date": "2017-08-15", "completion_date": "2018-11-30", "has_results": true, "last_update_posted_date": "2020-09-02", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 22, "location_summary": "Chandler, Arizona • Fayetteville, Arkansas • Beverly Hills, California + 19 more", "locations": [ { "city": "Chandler", "state": "Arizona" }, { "city": "Fayetteville", "state": "Arkansas" }, { "city": "Beverly Hills", "state": "California" }, { "city": "Palo Alto", "state": "California" }, { "city": "St. Helena", "state": "California" } ], "official_url": "https://clinicaltrials.gov/study/NCT03241810" }, { "nct_id": "NCT00044291", "title": "Phase III Study of Atamestane Plus Toremifene Versus Letrozole in Advanced Breast Cancer", "overall_status": "COMPLETED", "study_type": "INTERVENTIONAL", "phases": [ "PHASE3" ], "conditions": [ "Breast Neoplasms", "Neoplasms, Hormone-dependent" ], "interventions": [ { "name": "atamestane", "type": "DRUG" }, { "name": "toremifene", "type": "DRUG" }, { "name": "letrozole", "type": "DRUG" }, { "name": "aromatase inhibition", "type": "DRUG" }, { "name": "hormone therapy", "type": "PROCEDURE" }, { "name": "endocrine therapy", "type": "PROCEDURE" }, { "name": "antiestrogen therapy", "type": "PROCEDURE" } ], "intervention_types": [ "DRUG", "PROCEDURE" ], "sponsor": "Intarcia Therapeutics", "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": 865, "start_date": "2002-06", "completion_date": "2006-01", "has_results": false, "last_update_posted_date": "2015-07-31", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 17, "location_summary": "Lake Havasu City, Arizona • Tucson, Arizona • Greenbrae, California + 14 more", "locations": [ { "city": "Lake Havasu City", "state": "Arizona" }, { "city": "Tucson", "state": "Arizona" }, { "city": "Greenbrae", "state": "California" }, { "city": "San Diego", "state": "California" }, { "city": "Miami Shores", "state": "Florida" } ], "official_url": "https://clinicaltrials.gov/study/NCT00044291" }, { "nct_id": "NCT05012644", "title": "Comparative Real World Tumor Response in Pre-menopausal Metastatic Breast Cancer Patients Treated With Palbociclib + Aromatase Inhibitor or Aromatase Inhibitor Alone", "overall_status": "COMPLETED", "study_type": "OBSERVATIONAL", "phases": [], "conditions": [ "Metastatic Breast Cancer" ], "interventions": [ { "name": "Palbociclib + aromatase inhibitor", "type": "DRUG" }, { "name": "Aromatase inhibitor", "type": "DRUG" } ], "intervention_types": [ "DRUG" ], "sponsor": "Pfizer", "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": 197, "start_date": "2021-07-16", "completion_date": "2021-12-09", "has_results": true, "last_update_posted_date": "2024-10-08", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 1, "location_summary": "New York, New York", "locations": [ { "city": "New York", "state": "New York" } ], "official_url": "https://clinicaltrials.gov/study/NCT05012644" }, { "nct_id": "NCT01293032", "title": "Hormone Therapy Or Chemotherapy Before Surgery Based on Gene Expression Analysis in Treating Patients With Breast Cancer", "overall_status": "COMPLETED", "study_type": "INTERVENTIONAL", "phases": [ "NA" ], "conditions": [ "Ductal Breast Carcinoma in Situ", "Lobular Breast Carcinoma in Situ", "Stage II Breast Cancer", "Stage IIA Breast Cancer", "Stage IIB Breast Cancer", "Stage IIIA Breast Cancer", "Stage IIIB Breast Cancer" ], "interventions": [ { "name": "Neoadjuvant Therapy", "type": "PROCEDURE" }, { "name": "Therapeutic Conventional Surgery", "type": "PROCEDURE" }, { "name": "Laboratory Biomarker Analysis", "type": "OTHER" }, { "name": "Gene Expression Analysis", "type": "GENETIC" }, { "name": "Systemic Chemotherapy", "type": "DRUG" }, { "name": "Tamoxifen Citrate", "type": "DRUG" }, { "name": "Aromatase Inhibition Therapy", "type": "DRUG" } ], "intervention_types": [ "PROCEDURE", "OTHER", "GENETIC", "DRUG" ], "sponsor": "Virginia Commonwealth University", "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": 59, "start_date": "2011-04", "completion_date": "2016-03", "has_results": true, "last_update_posted_date": "2016-07-12", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 7, "location_summary": "Washington D.C., District of Columbia • Charlotte, North Carolina • Greensboro, North Carolina + 3 more", "locations": [ { "city": "Washington D.C.", "state": "District of Columbia" }, { "city": "Charlotte", "state": "North Carolina" }, { "city": "Charlotte", "state": "North Carolina" }, { "city": "Greensboro", "state": "North Carolina" }, { "city": "Houston", "state": "Texas" } ], "official_url": "https://clinicaltrials.gov/study/NCT01293032" }, { "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": "2026-10-05T05:48:00.078Z", "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": "NCT04352777", "title": "Impact of Endocrine Therapy and Abemaciclib on Host and Tumor Immune Cell Repertoire/Function in Advanced ER+/HER2- Breast Cancer", "overall_status": "COMPLETED", "study_type": "INTERVENTIONAL", "phases": [ "PHASE2" ], "conditions": [ "Metastatic Breast Cancer", "Locally Advanced Breast Cancer", "Hormone Receptor Positive Tumor" ], "interventions": [ { "name": "Abemaciclib", "type": "DRUG" }, { "name": "Fulvestrant", "type": "DRUG" }, { "name": "Aromatase Inhibitors", "type": "DRUG" } ], "intervention_types": [ "DRUG" ], "sponsor": "Duke University", "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": 18, "start_date": "2020-09-14", "completion_date": "2025-06-25", "has_results": false, "last_update_posted_date": "2025-07-20", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 1, "location_summary": "Durham, North Carolina", "locations": [ { "city": "Durham", "state": "North Carolina" } ], "official_url": "https://clinicaltrials.gov/study/NCT04352777" }, { "nct_id": "NCT00005970", "title": "Doxorubicin Hydrochloride, Cyclophosphamide, and Pacltaxel With or Without Trastuzumab in Treating Women With HER2-Positive Node-Positive or High-Risk Node-Negative Breast Cancer", "overall_status": "COMPLETED", "study_type": "INTERVENTIONAL", "phases": [ "PHASE3" ], "conditions": [ "Breast Adenocarcinoma", "HER2 Positive Breast Carcinoma", "Stage IA Breast Cancer AJCC v7", "Stage IB Breast Cancer AJCC v7", "Stage IIA Breast Cancer AJCC v6 and v7", "Stage IIB Breast Cancer AJCC v6 and v7", "Stage IIIA Breast Cancer AJCC v7" ], "interventions": [ { "name": "Aromatase Inhibition Therapy", "type": "DRUG" }, { "name": "Cyclophosphamide", "type": "DRUG" }, { "name": "Doxorubicin Hydrochloride", "type": "DRUG" }, { "name": "Laboratory Biomarker Analysis", "type": "OTHER" }, { "name": "Paclitaxel", "type": "DRUG" }, { "name": "Tamoxifen Citrate", "type": "DRUG" }, { "name": "Trastuzumab", "type": "BIOLOGICAL" } ], "intervention_types": [ "DRUG", "OTHER", "BIOLOGICAL" ], "sponsor": "National Cancer Institute (NCI)", "sponsor_class": "NIH", "healthy_volunteers": false, "eligibility": { "minimum_age": "18 Years", "maximum_age": null, "sex": "FEMALE", "summary": "18 Years and older · Female only" }, "enrollment_count": 3436, "start_date": "2000-05-19", "completion_date": "2010-01-27", "has_results": false, "last_update_posted_date": "2020-08-14", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 154, "location_summary": "Birmingham, Alabama • Phoenix, Arizona • Scottsdale, Arizona + 119 more", "locations": [ { "city": "Birmingham", "state": "Alabama" }, { "city": "Phoenix", "state": "Arizona" }, { "city": "Scottsdale", "state": "Arizona" }, { "city": "Tucson", "state": "Arizona" }, { "city": "Little Rock", "state": "Arkansas" } ], "official_url": "https://clinicaltrials.gov/study/NCT00005970" }, { "nct_id": "NCT02188745", "title": "ER Reactivation Therapy for Breast Cancer", "overall_status": "COMPLETED", "study_type": "INTERVENTIONAL", "phases": [ "PHASE2" ], "conditions": [ "Metastatic Breast Cancer" ], "interventions": [ { "name": "17B-estradiol", "type": "DRUG" }, { "name": "Letrozole", "type": "DRUG" }, { "name": "Anastrozole", "type": "DRUG" }, { "name": "Exemestane", "type": "DRUG" } ], "intervention_types": [ "DRUG" ], "sponsor": "Dartmouth-Hitchcock Medical 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": 20, "start_date": "2016-03-11", "completion_date": "2024-07-05", "has_results": true, "last_update_posted_date": "2026-09-25", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 3, "location_summary": "Springfield, Massachusetts • Rochester, Minnesota • Lebanon, New Hampshire", "locations": [ { "city": "Springfield", "state": "Massachusetts" }, { "city": "Rochester", "state": "Minnesota" }, { "city": "Lebanon", "state": "New Hampshire" } ], "official_url": "https://clinicaltrials.gov/study/NCT02188745" }, { "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": "2026-10-05T05:48:00.078Z", "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": "NCT02213042", "title": "Evaluation of Biomarkers Associated With Response to Subsequent Therapies in Subjects With HER2-Positive Metastatic Breast Cancer", "overall_status": "TERMINATED", "study_type": "INTERVENTIONAL", "phases": [ "PHASE2" ], "conditions": [ "Neoplasms, Breast" ], "interventions": [ { "name": "Lapatinib", "type": "DRUG" }, { "name": "Trastuzumab", "type": "BIOLOGICAL" }, { "name": "Aromatase Inhibitors (AIs)", "type": "DRUG" } ], "intervention_types": [ "DRUG", "BIOLOGICAL" ], "sponsor": "Novartis Pharmaceuticals", "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": 42, "start_date": "2014-10-24", "completion_date": "2020-06-04", "has_results": true, "last_update_posted_date": "2021-10-13", "last_synced_at": "2026-10-05T05:48:00.078Z", "location_count": 3, "location_summary": "Mobile, Alabama • Boston, Massachusetts • Houston, Texas", "locations": [ { "city": "Mobile", "state": "Alabama" }, { "city": "Boston", "state": "Massachusetts" }, { "city": "Houston", "state": "Texas" } ], "official_url": "https://clinicaltrials.gov/study/NCT02213042" } ] }