# ClinicalTrials.gov API: Search clinical trials > Finds ClinicalTrials.gov studies for a condition or medicine. You can filter by location, distance, recruitment status and phase. With a location, results are ordered by distance to the closest eligible site. Unofficial. Not affiliated with or endorsed by ClinicalTrials.gov. - Page: https://fous.com/methods/clinicaltrials.gov/search-trials - Method: `clinicaltrials.gov/search_trials`, version 1 - Website: clinicaltrials.gov - Returns: trial title, status, phase, sponsor, conditions, nearest site, distance, eligibility, contact, trial number, start date, link - Effect: read (it gets data and changes nothing) - Sign-in: none needed - Cost: 1 credit per completed run (1ยข with pay as you go); failed runs are free - Verified: Nov 2, 2026 ## Inputs | Field | Type | Required | In the run below | Description | |---|---|---|---|---| | `phase` | string | no | `"phase_3"` | Study phase, for example phase_3 or any. One of "any", "early_phase_1", "phase_1", "phase_2", "phase_3", "phase_4". Default "any". | | `location` | string | no | `"Boston, MA"` | City, state, or country for nearby trials, for example Boston, MA. Default "". | | `condition` | string | yes | `"breast cancer"` | Condition or medicine to search, for example breast cancer or semaglutide. | | `max_results` | integer | no | `5` | Maximum number of trials to return (up to 100). Default 20. | | `distance_miles` | number | no | `50` | Search radius in miles when a location is given, for example 50. Default 50. | | `recruiting_only` | boolean | no | `true` | Include only studies that are recruiting or preparing to recruit. Default true. | ## Output From a run on Oct 23, 2026, shortened. Its input: ```json { "phase": "phase_3", "location": "Boston, MA", "condition": "breast cancer", "max_results": 5, "distance_miles": 50, "recruiting_only": true } ``` Its output: ```json { "trials": [ { "sex": "All", "phase": "Phase 3", "status": "Recruiting", "sponsor": "Hoffmann-La Roche", "age_range": "18 Years and older", "conditions": [ "Breast Cancer" ], "start_date": "2023-06-07", "trial_link": "https://clinicaltrials.gov/study/NCT05646862", "trial_title": "A Study Evaluating the Efficacy and Safety of Inavolisib Plus Fulvestrant Compared With Alpelisib Plus Fulvestrant in Participants With HR-Positive, HER2-Negative, PIK3CA Mutated, Locally Advanced or Metastatic Breast Cancer Post CDK4/6i and Endocrine Combination Therapy", "contact_name": "Reference Study ID Number: WO43919 https://forpatients.roche.com/ No attachments to email below", "trial_number": "NCT05646862", "contact_email": "global-roche-genentech-trials@gene.com", "contact_phone": "888-662-6728 (U.S. and Canada)", "distance_miles": 0.1, "nearest_site_city": "Boston", "healthy_volunteers": false, "nearest_site_state": "Massachusetts", "nearest_site_country": "United States", "nearest_site_facility": "Massachusetts General Hospital" }, { "sex": "All", "phase": "Phase 3", "status": "Recruiting", "sponsor": "ECOG-ACRIN Cancer Research Group", "age_range": "18 Years and older", "conditions": [ "Plasma Cell Myeloma", "RISS Stage I Plasma Cell Myeloma", "RISS Stage II Plasma Cell Myeloma" ], "start_date": "2021-02-24", "trial_link": "https://clinicaltrials.gov/study/NCT04566328", "trial_title": "Testing the Use of Combination Therapy in Adult Patients With Newly Diagnosed Multiple Myeloma, the EQUATE Trial", "contact_name": "Site Public Contact", "trial_number": "NCT04566328", "contact_email": "ContactUsCancerCenter@TuftsMedicalCenter.org", "contact_phone": "617-636-5000", "distance_miles": 0.1, "nearest_site_city": "Boston", "healthy_volunteers": false, "nearest_site_state": "Massachusetts", "nearest_site_country": "United States", "nearest_site_facility": "Tufts Medical Center" }, { "sex": "All", "phase": "Phase 3", "status": "Recruiting", "sponsor": "NRG Oncology", "age_range": "18 Years and older", "conditions": [ "Muscle Invasive Bladder Urothelial Carcinoma", "Stage II Bladder Cancer AJCC v8", "Stage IIIA Bladder Cancer AJCC v8" ], "start_date": "2025-10-07", "trial_link": "https://clinicaltrials.gov/study/NCT07097142", "trial_title": "Testing Shorter Duration Radiation Therapy Versus the Usual Radiation Therapy in Patients Receiving the Usual Chemotherapy Treatment for Bladder Cancer, ARCHER Study", "contact_name": "Site Public Contact", "trial_number": "NCT07097142", "contact_email": null, "contact_phone": "877-726-5130", "distance_miles": 0.1, "nearest_site_city": "Boston", "healthy_volunteers": false, "nearest_site_state": "Massachusetts", "nearest_site_country": "United States", "nearest_site_facility": "Massachusetts General Hospital Cancer Center" } ] } ``` ## Run it From code, with a Fous API key in `FOUS_API_KEY`; the answer's `data` holds the output: ```bash curl https://api.fous.com/v1/runs \ -H "Authorization: Bearer $FOUS_API_KEY" \ -H "Content-Type: application/json" \ -d '{"method":"clinicaltrials.gov/search_trials","input":{"phase":"phase_3","location":"Boston, MA","condition":"breast cancer","max_results":5,"distance_miles":50,"recruiting_only":true}}' ``` From an AI agent connected to the Fous MCP server: its `run` with the same method and input. To connect one, give it `set up https://fous.com/SKILL.md`. ## Ask your agent - Find recruiting phase 3 trials for type 2 diabetes near Chicago, IL within 30 miles - Are there any open phase 2 studies testing pembrolizumab for lung cancer? - Show me early phase 1 trials for Alzheimer's disease in Austin, TX, sorted by closest site - I need phase 4 studies on semaglutide for obesity that are still enrolling, within 100 miles of Denver - List trials for asthma in Toronto, Canada, including eligibility and contact details, limited to 10 results ## Input schema ```json { "type": "object", "required": [ "condition" ], "properties": { "phase": { "enum": [ "any", "early_phase_1", "phase_1", "phase_2", "phase_3", "phase_4" ], "type": "string", "default": "any", "description": "Study phase, for example phase_3 or any." }, "location": { "type": "string", "default": "", "description": "City, state, or country for nearby trials, for example Boston, MA." }, "condition": { "type": "string", "minLength": 1, "description": "Condition or medicine to search, for example breast cancer or semaglutide." }, "max_results": { "type": "integer", "default": 20, "maximum": 100, "minimum": 1, "description": "Maximum number of trials to return (up to 100)." }, "distance_miles": { "type": "number", "default": 50, "minimum": 0.1, "description": "Search radius in miles when a location is given, for example 50." }, "recruiting_only": { "type": "boolean", "default": true, "description": "Include only studies that are recruiting or preparing to recruit." } } } ``` ## Output schema ```json { "type": "object", "required": [ "trials" ], "properties": { "trials": { "type": "array", "items": { "type": "object", "properties": { "sex": { "type": [ "string", "null" ] }, "phase": { "type": [ "string", "null" ] }, "status": { "type": [ "string", "null" ] }, "sponsor": { "type": [ "string", "null" ] }, "age_range": { "type": [ "string", "null" ] }, "conditions": { "type": "array", "items": { "type": "string" } }, "start_date": { "type": [ "string", "null" ] }, "trial_link": { "type": "string" }, "trial_title": { "type": [ "string", "null" ] }, "contact_name": { "type": [ "string", "null" ] }, "trial_number": { "type": "string" }, "contact_email": { "type": [ "string", "null" ] }, "contact_phone": { "type": [ "string", "null" ] }, "distance_miles": { "type": [ "number", "null" ] }, "nearest_site_city": { "type": [ "string", "null" ] }, "healthy_volunteers": { "type": [ "boolean", "null" ] }, "nearest_site_state": { "type": [ "string", "null" ] }, "nearest_site_country": { "type": [ "string", "null" ] }, "nearest_site_facility": { "type": [ "string", "null" ] } } } } } } ``` ## See more - [ClinicalTrials.gov API: List company trials](https://fous.com/methods/clinicaltrials.gov/list-company-trials.md): Lists ClinicalTrials.gov studies run or funded by a sponsor, newest start date first, with optional phase, status and condition filters. - [ClinicalTrials.gov API: Get clinical trial by NCT number or title](https://fous.com/methods/clinicaltrials.gov/get-trial.md): Returns the full public record of a ClinicalTrials.gov study, looked up by NCT number or by title (closest registered title for ambiguous titles). - [NIH API: Search PubMed articles](https://fous.com/methods/pubmed.ncbi.nlm.nih.gov/search-articles.md): Finds PubMed medical and life-science articles by topic, with publication details and free full-text links when PubMed confirms them. - [FDA API: Search drug recalls](https://fous.com/methods/open.fda.gov/search-drug-recalls.md): Finds FDA drug enforcement recalls by medicine or company name, newest first, with status, class, reason and quantity. Recent recalls may not yet appear. - [NIH API: Search grants](https://fous.com/methods/reporter.nih.gov/search-grants.md): Finds NIH research grants by topic, organisation, or researcher name. Searches the last five fiscal years by default. - [Grants.gov API: Search grant opportunities](https://fous.com/methods/grants.gov/search-grants.md): Finds U.S. federal grant opportunities by topic, agency, applicant type and status, with funding and eligibility details. Open results exclude opportunities whose closing date has passed. - [FDA API: Search medical device recalls](https://fous.com/methods/fda.gov/search-device-recalls.md): Finds FDA medical device recalls whose product description or recalling company matches a phrase, newest first, with the recall class and its health-risk meaning from each FDA recall page. An optional start date limits recalls to those initiated on or after it. - [Medicare API: Search hospitals](https://fous.com/methods/medicare.gov/search-hospitals.md): Finds U.S. hospitals by name, city and state, or ZIP code, with Medicare overall and patient survey star ratings, contact details, and Care Compare links. Ratings may be unavailable for some hospitals. - [All ClinicalTrials.gov methods](https://fous.com/methods/clinicaltrials.gov.md)