ClinicalTrials.gov API: trial search & NCT dossier

Answers "which trials?" and "where does this trial stand?" in one call: status, phase, sponsor, conditions, drugs, enrollment, start and primary completion dates, site countries, primary outcomes and whether results are posted, as one compact JSON row per trial with a link to its ClinicalTrials.gov record. Built for AI agents and people in pharma, biotech, health research and investing.

Pricing (pay per event): $0.004 per trial returned. Invalid input, unknown NCT numbers and empty searches cost nothing.

Questions agents ask

• “What is the status and primary completion date of NCT05813925? Cite the ClinicalTrials.gov record.”

{ "nctIds": ["NCT05813925", "NCT04368728"] }

{
  "nct_id": "NCT05813925",
  "title": "A Research Study to See How Well CagriSema Helps People in East Asia With Excess Body Weight Lose Weight",
  "acronym": null,
  "status": "COMPLETED",
  "phases": ["PHASE3"],
  "study_type": "INTERVENTIONAL",
  "conditions": ["Obesity or Overweight"],
  "interventions": [
    { "type": "DRUG", "name": "Cagrilintide" },
    { "type": "DRUG", "name": "Semaglutide" },
    { "type": "DRUG", "name": "Placebo Semaglutide" }
  ],
  "sponsor": "Novo Nordisk A/S",
  "sponsor_class": "INDUSTRY",
  "collaborators": [],
  "enrollment_count": 331,
  "enrollment_type": "ACTUAL",
  "start_date": "2023-04-03",
  "start_date_type": "ACTUAL",
  "primary_completion_date": "2025-01-17",
  "primary_completion_date_type": "ACTUAL",
  "completion_date": "2025-03-07",
  "completion_date_type": "ACTUAL",
  "last_update_posted": "2026-01-22",
  "countries": ["Japan", "Taiwan"],
  "site_count": 28,
  "primary_outcomes": [
    {
      "measure": "Relative Change in Body Weight",
      "time_frame": "From baseline (week 0) to end of treatment (week 68)"
    }
  ],
  "primary_outcomes_total": 1,
  "has_results": false,
  "results_first_posted": null,
  "brief_summary": "This study will look at how well the new medicine CagriSema helps people with excess body weight lose weight compared to another medicine, semaglutide. The participants will receive one injection once a week. The study medicine will be injected with a thin needle, typically in the stomach, thighs or upper arms. The study will last for about 1½ years.",
  "eligibility": null,
  "arms": null,
  "secondary_outcomes": null,
  "sites": null,
  "source_url": "https://clinicaltrials.gov/study/NCT05813925",
  "data_processed_at": "2026-11-05T10:00:06",
  "retrieved_at": "2026-11-05T22:38:47+00:00",
  "attribution": "Source: ClinicalTrials.gov, a U.S. Government database of the National Library of Medicine (https://clinicaltrials.gov). Data processed by ClinicalTrials.gov on 2026-11-05; data retrieved on 2026-11-05. Modified by Bosco Labs: selected fields only, personal contact details removed, long texts and lists shortened (cut texts end with [truncated]).",
  "schema_version": "1"
}

What you get

Use with AI agents (MCP)

Add this URL to your MCP client (Claude, Cursor, VS Code, ...) to load the Actor as a tool through the Apify hosted MCP server. It signs you in with OAuth or accepts Authorization: Bearer <APIFY_TOKEN>. It works once the Actor is live on the Apify Store.

https://mcp.apify.com?tools=bosco_labs/clinical-trials

For “What is the status and primary completion date of NCT05813925? Cite the ClinicalTrials.gov record.” the agent passes:

{ "nctIds": ["NCT05813925"] }

one row per trial (about 2-3 KB in summary mode), stable snake_case fields, ISO dates, numbers as numbers, null for unknown, a source_url per row. The run's status message says how many trials matched in total (e.g. "20 of 131 matching trials"), which NCT numbers were not found, or why a search was empty. Typical run: under 5 seconds including start-up.

Or call the Apify API: POST https://api.apify.com/v2/acts/bosco_labs~clinical-trials/run-sync-get-dataset-items with the input as JSON body. Cost: $0.004 per trial.

Input fields

Sources, licence and limits

How fresh is it? Live: every run queries ClinicalTrials.gov, which updates its data daily (data_processed_at is its latest processing time). Sponsors update their own records, so a status can lag reality; last_update_posted shows when the record last changed.

Does "recruiting in Europe" mean the European sites are recruiting? It means the trial's overall status is recruiting and at least one site is in Europe. Per-site status is in sites[].status with detail: "full".

Why does a drug class like "GLP-1" find few trials? The intervention search matches what registrants wrote. Name the molecules (semaglutide OR tirzepatide ...) for full coverage.

Are results (outcome data) included? has_results and results_first_posted say whether and when results were posted; the result tables themselves are not included (open source_url).

What is left out? Contact persons, investigators and officials (names, emails, phones); the responsible-party investigator; detailed descriptions, references, IPD-sharing and oversight details. When the record lists a private individual as lead sponsor (class INDIV), sponsor is null; some sponsor-investigators are registered under class OTHER and do appear by name, as on ClinicalTrials.gov.

Coverage? Everything on ClinicalTrials.gov (over 500,000 studies worldwide, US and non-US). Trials registered only elsewhere (EU CTIS, ISRCTN, jRCT, ...) are not included.

Not medical advice. This is registry data for research; patients should talk to their doctor and the study team listed on ClinicalTrials.gov.

Data from ClinicalTrials.gov, a database of the U.S. National Library of Medicine (U.S. Government); not endorsed by NLM or NIH. Following the ClinicalTrials.gov Terms and Conditions, every row credits ClinicalTrials.gov, shows the date ClinicalTrials.gov processed the data (data_processed_at) and the retrieval date, and states the modifications: only the fields above are kept, personal contact details are removed, and long texts and lists are shortened (cut texts end with [truncated]; the caps are listed above). No proprietary rights are claimed. Don't use any contact information from ClinicalTrials.gov for marketing. Some data may be subject to third-party copyright; keep data you store current.