{"chart":{"slug":"clinical-trials-by-phase","title":"How many clinical trials are in each phase?","takeaway":"52% of the 466,000 clinical trials registered on ClinicalTrials.gov as of November 2026, some 241,000, have no phase: phases describe drug trials, and these test devices, surgery, behavior or diet. Among drug trials, Phase 2 is the most common with about 66,000. Phase 1 tests safety in a few people, Phase 2 asks whether a treatment works and at what dose, Phase 3 compares a treatment with the usual care in many, and Phase 4 follows a drug after approval.","topic":"Clinical trials","chart_type":"bar","ranking":false,"x_label":"Phase","y_label":"Clinical trials (all years)","unit":null,"points_count":8,"source":{"name":"ClinicalTrials.gov (U.S. National Library of Medicine), counted with its API v2","url":"https://clinicaltrials.gov/data-api/api"},"license":{"name":"Public domain (U.S. government work); source National Library of Medicine","url":"https://www.nlm.nih.gov/web_policies.html#copyright"},"data_as_of":"2026-11-04","updated_at":"2026-11-04T17:18:26.222Z","url":"https://chart.ly/charts/clinical-trials-by-phase","api_url":"https://chart.ly/api/v1/charts/clinical-trials-by-phase","csv_url":"https://chart.ly/charts/clinical-trials-by-phase/data.csv","image_url":"https://chart.ly/charts/clinical-trials-by-phase/image.png","embed_url":"https://chart.ly/charts/clinical-trials-by-phase/embed","credit":"ClinicalTrials.gov (U.S. National Library of Medicine), counted with its API v2, via Chartly (https://chart.ly/charts/clinical-trials-by-phase)","credit_html":"ClinicalTrials.gov (U.S. National Library of Medicine), counted with its API v2, via \u003ca href=\"https://chart.ly/charts/clinical-trials-by-phase\"\u003eChartly\u003c/a\u003e","average_label":null,"zero_axis":true,"data":[{"label":"Early Phase 1","value":6536},{"label":"Phase 1","value":49013},{"label":"Phase 1/2","value":17185},{"label":"Phase 2","value":66042},{"label":"Phase 2/3","value":7644},{"label":"Phase 3","value":42522},{"label":"Phase 4","value":36059},{"label":"No phase (devices, behavior, etc.)","value":240567}],"annotations":[]},"docs":"https://chart.ly/developers","terms":"Free to use with credit: wherever you show or quote a chart's data, name Chartly with a link to that chart's url (each chart's credit line does both) and credit its source as its license asks.","credit":"ClinicalTrials.gov (U.S. National Library of Medicine), counted with its API v2, via Chartly (https://chart.ly/charts/clinical-trials-by-phase)"}