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Clinical trials

Observational trials in the United States

Search ClinicalTrials.gov registrations by keyword, then narrow by condition, phase, status, country and start year.

Filters: Phase: Observational Country / region: United States Clear all

31,637 trials match Source: ClinicalTrials.gov registrations

Trials started per year

By phase, 2000 to 2026.

Trials started per year
CategoryTrials
2000205
2001274
2002312
2003458
2004564
2005742
2006912
20071,058
20081,184
20091,206
20101,275
20111,286
20121,316
20131,292
20141,380
20151,308
20161,322
20171,502
20181,408
20191,529
20201,743
20211,794
20221,482
20231,476
20241,325
20251,218
2026988

Status

Trials by registry status. Select a bar to filter.

Trials by status
CategoryTrials
Completed18,848
Recruiting4,280
Terminated2,465
Unknown status2,105
Active, not recruiting1,634
Withdrawn1,143
Enrolling by invitation646
Not yet recruiting394
Suspended122

Top lead sponsors

A sponsor with a page on Pharma Observatory links to it.

Top lead sponsors
CategoryTrials
Mayo Clinic756
M.D. Anderson Cancer Center493
Memorial Sloan Kettering Cancer Center432
National Institute of Allergy and Infectious Diseases (NIAID)410
National Cancer Institute (NCI)407
Duke University390
Stanford University386
National Institute of Neurological Disorders and Stroke (NINDS)379
Massachusetts General Hospital364
University of California, San Francisco344

Top conditions

MeSH conditions the trials were registered with, not their broader categories. A condition with a page on Pharma Observatory links to it.

Top conditions
CategoryTrials
Breast Neoplasms1,006
Neoplasms897
Obesity651
Heart Failure512
Diabetes Mellitus506
COVID-19504
Prostatic Neoplasms461
Lung Neoplasms437
Cardiovascular Diseases380
Parkinson Disease375

Trials

Showing 51 to 75 of 31,637. Each trial links to its page on Pharma Observatory.

31,537 more trials match. See them on Pharma Observatory

Recently changed trials

Changes observed in the last 7 days, newest first, site-count changes left out. Source: ClinicalTrials.gov.

Go deeper on Pharma Observatory

Pharma Observatory connects clinical trials, sponsors, sites and investigators in one searchable platform.