{
  "api_version": "1",
  "request": {
    "url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=Letrozole+placebo",
    "query": {
      "intervention": "Letrozole placebo"
    },
    "page_size": 10
  },
  "pagination": {
    "page": 1,
    "page_size": 10,
    "total_count": 40,
    "total_pages": 4,
    "next_page_url": "https://clinicaltrialsfind.com/api/v1/search.json?intervention=Letrozole+placebo&page=2&page_size=10",
    "previous_page_url": null
  },
  "source": "remote",
  "last_synced_at": "2026-09-14T19:38:15.410Z",
  "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": "NCT07085767",
      "title": "Palazestrant in Combination With Ribociclib for the First-line Treatment of ER+/HER2- Advanced Breast Cancer",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Breast Cancer",
        "Locally Advanced Breast Cancer",
        "Metastatic Breast Cancer",
        "ER Positive Breast Cancer",
        "HER2 Negative Breast Carcinoma"
      ],
      "interventions": [
        {
          "name": "Palazestrant",
          "type": "DRUG"
        },
        {
          "name": "Letrozole-matching placebo",
          "type": "DRUG"
        },
        {
          "name": "Ribociclib",
          "type": "DRUG"
        },
        {
          "name": "Letrozole",
          "type": "DRUG"
        },
        {
          "name": "Palazestrant matching-placebo",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Olema Pharmaceuticals, Inc.",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 1000,
      "start_date": "2025-11-03",
      "completion_date": "2032-01",
      "has_results": false,
      "last_update_posted_date": "2026-08-17",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 47,
      "location_summary": "Hot Springs, Arkansas • Beverly Hills, California • La Jolla, California + 44 more",
      "locations": [
        {
          "city": "Hot Springs",
          "state": "Arkansas"
        },
        {
          "city": "Beverly Hills",
          "state": "California"
        },
        {
          "city": "La Jolla",
          "state": "California"
        },
        {
          "city": "Los Alamitos",
          "state": "California"
        },
        {
          "city": "San Francisco",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT07085767"
    },
    {
      "nct_id": "NCT00867217",
      "title": "Vitamin D3 for Aromatase Inhibitor Induced Arthralgias",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Breast Cancer"
      ],
      "interventions": [
        {
          "name": "High Dose Vitamin D",
          "type": "DIETARY_SUPPLEMENT"
        },
        {
          "name": "Placebo",
          "type": "DIETARY_SUPPLEMENT"
        },
        {
          "name": "Standard Dose Vitamin D3",
          "type": "DIETARY_SUPPLEMENT"
        },
        {
          "name": "Letrozole 2.5mg",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DIETARY_SUPPLEMENT",
        "DRUG"
      ],
      "sponsor": "Qamar Khan",
      "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": 160,
      "start_date": "2009-03",
      "completion_date": "2011-01",
      "has_results": true,
      "last_update_posted_date": "2018-02-09",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 2,
      "location_summary": "Westwood, Kansas • Wichita, Kansas",
      "locations": [
        {
          "city": "Westwood",
          "state": "Kansas"
        },
        {
          "city": "Wichita",
          "state": "Kansas"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00867217"
    },
    {
      "nct_id": "NCT00634894",
      "title": "Femara (Letrozole) Versus Placebo for Patients With Ovarian, Fallopian Tube, or Primary Peritoneal Cancer",
      "overall_status": "WITHDRAWN",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Ovarian Cancer",
        "Fallopian Tube Cancer",
        "Peritoneal Cancer"
      ],
      "interventions": [
        {
          "name": "Femara",
          "type": "DRUG"
        },
        {
          "name": "Placebo",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "M.D. Anderson Cancer Center",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": null,
        "maximum_age": null,
        "sex": "FEMALE",
        "summary": "Female only"
      },
      "enrollment_count": 0,
      "start_date": "2008-03",
      "completion_date": "2008-09",
      "has_results": false,
      "last_update_posted_date": "2016-04-20",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 1,
      "location_summary": "Houston, Texas",
      "locations": [
        {
          "city": "Houston",
          "state": "Texas"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00634894"
    },
    {
      "nct_id": "NCT04546009",
      "title": "A Study Evaluating the Efficacy and Safety of Giredestrant Combined With Palbociclib Compared With Letrozole Combined With Palbociclib in Participants With Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer (persevERA Breast Cancer)",
      "overall_status": "ACTIVE_NOT_RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer"
      ],
      "interventions": [
        {
          "name": "Giredestrant",
          "type": "DRUG"
        },
        {
          "name": "Giredestrant-matched Placebo",
          "type": "DRUG"
        },
        {
          "name": "Letrozole",
          "type": "DRUG"
        },
        {
          "name": "Letrozole-matched Placebo",
          "type": "DRUG"
        },
        {
          "name": "Palbociclib",
          "type": "DRUG"
        },
        {
          "name": "LHRH Agonist",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "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": 992,
      "start_date": "2020-10-09",
      "completion_date": "2027-07-31",
      "has_results": false,
      "last_update_posted_date": "2026-08-17",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 37,
      "location_summary": "Fountain Valley, California • Long Beach, California • San Leandro, California + 32 more",
      "locations": [
        {
          "city": "Fountain Valley",
          "state": "California"
        },
        {
          "city": "Long Beach",
          "state": "California"
        },
        {
          "city": "San Leandro",
          "state": "California"
        },
        {
          "city": "Stanford",
          "state": "California"
        },
        {
          "city": "Walnut Creek",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04546009"
    },
    {
      "nct_id": "NCT04478266",
      "title": "Amcenestrant (SAR439859) Plus Palbociclib as First Line Therapy for Patients With ER (+) HER2(-) Advanced Breast Cancer",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Breast Cancer"
      ],
      "interventions": [
        {
          "name": "Amcenestrant-matching placebo",
          "type": "DRUG"
        },
        {
          "name": "SAR439859",
          "type": "DRUG"
        },
        {
          "name": "Palbociclib",
          "type": "DRUG"
        },
        {
          "name": "Letrozole",
          "type": "DRUG"
        },
        {
          "name": "Goserelin",
          "type": "DRUG"
        },
        {
          "name": "Letrozole-matching placebo",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Sanofi",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 1068,
      "start_date": "2020-10-14",
      "completion_date": "2023-05-26",
      "has_results": true,
      "last_update_posted_date": "2025-09-11",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 45,
      "location_summary": "Daphne, Alabama • Glendale, Arizona • Tucson, Arizona + 40 more",
      "locations": [
        {
          "city": "Daphne",
          "state": "Alabama"
        },
        {
          "city": "Glendale",
          "state": "Arizona"
        },
        {
          "city": "Tucson",
          "state": "Arizona"
        },
        {
          "city": "Fullerton",
          "state": "California"
        },
        {
          "city": "Los Alamitos",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT04478266"
    },
    {
      "nct_id": "NCT05894239",
      "title": "A Study to Evaluate the Efficacy and Safety of Inavolisib in Combination With Phesgo Versus Placebo in Combination With Phesgo in Participants With PIK3CA-Mutated HER2-Positive Locally Advanced or Metastatic Breast Cancer",
      "overall_status": "RECRUITING",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Metastatic Breast Cancer"
      ],
      "interventions": [
        {
          "name": "Inavolisib",
          "type": "DRUG"
        },
        {
          "name": "Phesgo",
          "type": "DRUG"
        },
        {
          "name": "Placebo",
          "type": "DRUG"
        },
        {
          "name": "Taxane-based Chemotherapy",
          "type": "DRUG"
        },
        {
          "name": "Optional Endocrine Therapy of Investigator's Choice",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "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": 230,
      "start_date": "2023-09-08",
      "completion_date": "2032-12-28",
      "has_results": false,
      "last_update_posted_date": "2026-08-25",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 20,
      "location_summary": "Gilbert, Arizona • Burbank, California • Corona, California + 17 more",
      "locations": [
        {
          "city": "Gilbert",
          "state": "Arizona"
        },
        {
          "city": "Burbank",
          "state": "California"
        },
        {
          "city": "Corona",
          "state": "California"
        },
        {
          "city": "Duarte",
          "state": "California"
        },
        {
          "city": "Irvine",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT05894239"
    },
    {
      "nct_id": "NCT03078751",
      "title": "Adjuvant Ribociclib With Endocrine Therapy in Hormone Receptor+/HER2- High Risk Early Breast Cancer",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Breast Cancer"
      ],
      "interventions": [
        {
          "name": "Ribociclib",
          "type": "DRUG"
        },
        {
          "name": "Adjuvant endocrine therapy",
          "type": "DRUG"
        },
        {
          "name": "Placebo",
          "type": "DRUG"
        }
      ],
      "intervention_types": [
        "DRUG"
      ],
      "sponsor": "Novartis Pharmaceuticals",
      "sponsor_class": "INDUSTRY",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": null,
        "sex": "ALL",
        "summary": "18 Years and older"
      },
      "enrollment_count": 54,
      "start_date": "2017-06-20",
      "completion_date": "2020-03-09",
      "has_results": true,
      "last_update_posted_date": "2021-10-11",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 33,
      "location_summary": "Tucson, Arizona • Fayetteville, Arkansas • Bakersfield, California + 28 more",
      "locations": [
        {
          "city": "Tucson",
          "state": "Arizona"
        },
        {
          "city": "Fayetteville",
          "state": "Arkansas"
        },
        {
          "city": "Bakersfield",
          "state": "California"
        },
        {
          "city": "Los Angeles",
          "state": "California"
        },
        {
          "city": "Oxnard",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT03078751"
    },
    {
      "nct_id": "NCT01740427",
      "title": "A Study of Palbociclib (PD-0332991) + Letrozole vs. Letrozole For 1st Line Treatment Of Postmenopausal Women With ER+/HER2- Advanced Breast Cancer (PALOMA-2)",
      "overall_status": "COMPLETED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE3"
      ],
      "conditions": [
        "Breast Neoplasms"
      ],
      "interventions": [
        {
          "name": "PD-0332991",
          "type": "DRUG"
        },
        {
          "name": "Letrozole",
          "type": "DRUG"
        },
        {
          "name": "Placebo",
          "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": 666,
      "start_date": "2013-02-22",
      "completion_date": "2023-11-09",
      "has_results": true,
      "last_update_posted_date": "2024-11-14",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 136,
      "location_summary": "Bellflower, California • Beverly Hills, California • Fullerton, California + 83 more",
      "locations": [
        {
          "city": "Bellflower",
          "state": "California"
        },
        {
          "city": "Beverly Hills",
          "state": "California"
        },
        {
          "city": "Fullerton",
          "state": "California"
        },
        {
          "city": "Glendale",
          "state": "California"
        },
        {
          "city": "Irvine",
          "state": "California"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT01740427"
    },
    {
      "nct_id": "NCT00573755",
      "title": "Sorafenib and Letrozole, Anastrozole, or Exemestane in Treating Postmenopausal Women With Estrogen Receptor-Positive and/or Progesterone Receptor-Positive Metastatic Breast Cancer",
      "overall_status": "TERMINATED",
      "study_type": "INTERVENTIONAL",
      "phases": [
        "PHASE2"
      ],
      "conditions": [
        "Breast Cancer"
      ],
      "interventions": [
        {
          "name": "anastrozole",
          "type": "DRUG"
        },
        {
          "name": "exemestane",
          "type": "DRUG"
        },
        {
          "name": "letrozole",
          "type": "DRUG"
        },
        {
          "name": "sorafenib tosylate",
          "type": "DRUG"
        },
        {
          "name": "placebo",
          "type": "OTHER"
        }
      ],
      "intervention_types": [
        "DRUG",
        "OTHER"
      ],
      "sponsor": "Mayo Clinic",
      "sponsor_class": "OTHER",
      "healthy_volunteers": false,
      "eligibility": {
        "minimum_age": "18 Years",
        "maximum_age": "120 Years",
        "sex": "FEMALE",
        "summary": "18 Years to 120 Years · Female only"
      },
      "enrollment_count": 4,
      "start_date": "2007-12",
      "completion_date": "2013-04",
      "has_results": true,
      "last_update_posted_date": "2016-02-05",
      "last_synced_at": "2026-09-14T19:38:15.410Z",
      "location_count": 3,
      "location_summary": "Scottsdale, Arizona • Jacksonville, Florida • Rochester, Minnesota",
      "locations": [
        {
          "city": "Scottsdale",
          "state": "Arizona"
        },
        {
          "city": "Jacksonville",
          "state": "Florida"
        },
        {
          "city": "Rochester",
          "state": "Minnesota"
        }
      ],
      "official_url": "https://clinicaltrials.gov/study/NCT00573755"
    },
    {
      "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": "2026-09-14T19:38:15.410Z",
      "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"
    }
  ]
}